Am J Physiol Heart Circ Physiol-1999-Chao-H2127-34

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276:H2127-H2134, 1999. ;Am J Physiol Heart Circ PhysiolC. LonghurstDong M. Chao, Lin L. Shen, Stephanie Tjen-A-Looi, Koullis F. Pitsillides, Peng Li and Johnon sympathetic cardiovascular reflex responsesNaloxone reverses inhibitory effect of electroacupuncture

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Naloxone reverses inhibitory effect of electroacupuncture

on sympa t hetic ca rdiova scular refl ex responses

D ON G M . CHA O,1 L I N L . S H E N ,1 STEPHANIE TJ EN-A-LOOI,2 K OUL L I S F . PI T S I L L I D ES ,3

P E N G L I ,1 AN D J O H N C . L O N G H U R S T2

1Departm ent of Physiology, Shanghai M edi cal U ni ver sit y, Shanghai 200032, Peoples Republ icof China; 3Division of Cardiovascular Medicine, Department of Internal Medicine and Human

Physiology, U niversi ty of Cal i forn ia, D avis, Cal i forni a 95616; and 2Department of Medicine,Un iversi ty of Cal i forn i a, I rv ine, Cal i forn i a 92868

Chao, Dong M., Lin L. Shen, Stephanie Tjen-A-Looi,Koullis F. Pitsillides, Peng Li , and J ohn C. Longhurst.Na loxone reverses inh ibitory effect of electroacupuncture onsympathetic cardiovascular reflex responses. Am. J . Physiol .276 (Heart Circ. Physiol. 45): H2127H2134, 1999.Acupunc-t ure a nd elect roa cupunct ure (EA) ha ve been us ed in t ra di-tional Ch inese medicine to treat a wide ra nge of diseases andconditions, including angina pectoris and myocardial infarc-tion. In a feline model of reflex-induced reversible myocar diali s ch e m ia , e le ct r i ca l s t i m ul a t i on of t h e m e d ia n n e r ve s t omimic EA (Neigua n a cupoint ) s ignifica nt ly improved is ch-

emic dysfunction, secondary to an inhibitory effect of EA onreflex pressor effects evoked by bra dykinin (BK ). The centra lmecha nism of EAs inhibit ory effect in th is model is unknown .Accordingly, in -chloralose-a nesth etized cat s, B K (10 g/ml)wa s applied to the gallbladd er to elicit a car diovascular reflexres ponse t ha t s ignifica nt ly (P 0.05) increased arterial bloodpress ure a nd hea rt ra t e; norma lized s ys t olic w a ll t hickening(%WTh) of t he left ventricle, measur ed by ultra sonic single-crystal sonomicrometer, increased by 31 11% (P 0.05).After ligat ion of a side bra nch of the left ant erior descendingcoronary ar tery, the reflex pressor response to BK r esulted ina signifi cant decrea se of %WTh (32 6%) in th e ischem icr e g i o n . W h e n b i l a t e r a l E A o f t h e N e i g u a n a c u p o i n t s w a sp er f or m e d, t h e p r es s or r e sp on s e t o B K w a s i n h ib it e d a n dregional myocar dial function wa s significan tly improved (19 20%). The in hibit ory effects of EA on blood pressur e a nd%WTh were reversed by intra venous injection of na loxone(0.4 m g/kg ; n 9) or m icroinjection of n a loxone (10 nM in 0.1l/si t e; n 14) into the rostral ventr olatera l medulla (rVLM).Thus %WTh w ith intra venous naloxone wa s reduced t o 13 29%(P0.05) during stimulation of the gallbladder. Ourr e su l t s i n d i ca t e t h a t t h e i n h ib i t or y e ff ect of E A o n t h eBK-induced pressor response and the consequent improve-ment of ischemic dysfunction is dependent on the activationof opioid receptors, specifi cally r eceptors locat ed in th e rVLM.

pressor response; myocardial ischemia; rostral ventrolateralmedulla; syst olic wall th ickening

E P I D E M I O L OG I C S TU D I E S h ave d e m o n strate d a re lat io n -sh ip b etw e en g al lb lad d e r d isease an d coron ar y art e rydisease (5, 39). Removal of a diseased ga llbla dder canreduce angina pectoris or electrocardiographic irregu-larities (27, 41). The diseased gallbladder likely pro-duces bradykinin (BK), because BK is known to be anin fla m m a to ry m e d iato r p rod u ce d b y visce ral org an s

(42). In this regard, previous experiments (26, 29, 30)indicated that application of BK to the serosal surfaceof the gallbladder stimulates chemosensitive endings ofa f fer en t fi b er s t h a t t r a v el i n s pl a n ch n ic n er v es t oreflexly a ctivat e the cardiovascular system. The cardio-va scular r esponse includes a pressor response, ta chycar-d ia, an d in cre ase s in le f t ve n tricu lar p re ssu re (L V P)a nd t he fi rst derivative of LVP (LV dP /d t), responsesth at can e vo k e m yo card ial isch e m ia in h e arts with acompromised coronary circulation (18).

I n tra d i t ion al Ch in e se m e d icin e, acu p un ctu re h asb e e n u se d fo r ce n tu rie s to tre at a varie ty o f d ise ase sand disorders (22, 42). Clinical evidence indicates thatacu pu n ctu re m ay h ave th e rap e utic e ffects on som etypes of hypertension, coronary heart disease, arrh yth -mias, angina pectoris, and myocardial infarction (2, 8,10, 33, 38). Studies in anesthetized animals (19) alsoh ave d e m on stra te d b en e fi cial e ffects of acu p un ctu rea nd electroacupuncture (EA) on myoca rdia l ischemia,a rrhyt hmia s, hypertension, a nd hypotension. Recently,ou r lab orat ory (18) fou n d th a t th e card iovascu lar re -sponses and the resultant myocardial ischemia causedb y t h e in cre ase in m yocard ial o xyg en d e m an d d u rin ga pplica tion of BK on the gallbladder in ca ts w ith part ialocclusion of the coronary artery could be inhibited byEA-like bilat eral st imulat ion of the m edian n erve.

The effects of EA on the card iovascula r syst em likelyare th e re su lt o f e xci tat io n o f g ro u p I I I an d p o ssib lygroup IV a fferent fi bers beneath the a cupoint (18, 21).P r e v iou s w o r k h a s d em on s t r a t e d t h a t s u ch a f fe re ntinputs can activate a sympathetic inhibitory system inthe brain, resulting in the release of endogenous opi-oids, -amino-n-buty ric a cid a nd serotonin (17). Thesem ed ia t or s ca n i n hi bi t s y m pa t h et i c n e u r on s i n t h en u cleu s p ara g igan t oce llu lar is late ra l is (P G L ) o f th erostral ventrolateral medulla (rVLM) (14, 15, 17), animportant center responsible, in part, for maintaining

b lood p ressu re (B P ) a n d in te gra tin g card iovascu larreflexes (3, 36).The presence of opioid receptors in the central ner-

vous system (CNS) (12), including the rVLM (6, 28),a n d t h e ir r ol e i n r e gu la t i on of t h e ca r d i ov a s cu la rsystem have been reported previously (6, 28, 32, 37).Previous work by one member of our group (37) hasshown that microinjection of opioid agonists into ther V L M s t e a d i l y d e c r e a s e s B P a n d h e a r t r a t e ( H R ) i nnormotensive, chronic str ess-induced hypertens ive andsp on ta n e ou sly h yp erte n sive ra ts , wh e re as n alo xon einjected into the rVLM blocks this effect (37). Others

The costs of publication of this article were defrayed in part by thep a y m e n t of p a g e c h a r g es . Th e a r t ic le m u s t t h e r ef or e b e h e r e b ymarked advertisement in accordan ce with 18 U.S.C. Sect ion 1734solely to indicate this fact.

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ha ve reported tha t injection of opioid a gonists into th erVLM inhibits the pressor responses to carotid occlu-sion (32) and muscular contraction (6). However, thereis no evidence a t present to implica te t he endogenousopioid sys tem in th e rVLM in th e acupunctu re-inducedinhibition of myoca rdia l ischemia provoked by reflexsympa thetic stimula tion of the nervous syst em.

In t he present study, therefore, we hypothesized th a t

th e m e ch an ism o f th e in h ib i to ry e f fe ct o f EA o n th ega llbla dder-induced pressor response a nd on regiona ldemand-induced cardiac ischemia is opioid related andoccu rs in t h e P G L of t h e rV L M . To in vestig ate th ishypothesis, w e ut ilized percuta neous EA in our felinemodel of repeat a ble, reversible, reflex-induced myocar-dial ischemia , before and a fter the adm inistra tion of anopioid a nta gonist, n a loxone, either intr avenously or bymicroinjection into the PGL. A preliminary report onth is work ha s been presented (7).

METHODS

Surgical Preparation

St udies were performed on ad ult cat s of either sex (2.44.7k g ). An e st h e si a w a s i n it i a l ly i n d uce d w i t h k et a m i n e (4 0mg/kg im). The right femoral vein w as cannula ted t o enablea dminis t ra t ion of -chlora lose (50 mg/kg) a nd other drugs.Supplementa ry doses of -chlora lose (10 mg /kg iv) w ere givenw henever neces s a ry t o ma int a in a n a dequa t e dept h of a nes -thesia , a s a ssessed by la ck of response to noxious toe pinch, ares pira t ory pa t t ern t ha t follow ed t he vent ila t or , a nd s t a bleB P . I n t u b a t i o n o f t h e t r a c h ea w a s p er f or m e d f or a r t i fi c i a lv en t i la t i on . A r t er i a l b lood g a s e s a n d p H w e r e m e a s ur e dfrequently with a blood gas analyzer (model M168, ShanghaiM edica l A na lyt ic I ns t rument Fa ct ory, Sha ngha i, P R C) a ndma int a ined w it hin t he norma l ra nge (P C O2 3235 mmH g; P O210 0 m m H g ) b y e n r ic hi n g t h e i n sp ir e d O2 s u pp ly a n da d j us t i n g t h e v en t i la t o r y r a t e or v ol u m e. Ar t e r ia l p H w a s

kept between 7.32 an d 7.43 and wa s corrected as n ecessary byt he infus ion of 8% s odium bica rbona t e. B ody t empera t urew a s m on it or ed w i t h a r ect a l p rob e a n d w a s m a i n t a in edbet w een 36. 5 a nd 37. 5 C by a t hermos t a t ica lly cont rolledhea t ing pa d. Sys t emic B P w a s mea s ured t hrough a ca nnulains ert ed int o t he femora l a r t ery, w hich w a s connect ed t o apressur e t ra nsdu cer (model TP -101T, Nih on K ohden, Tokyo,J apan). Mean arterial pressure (MAP) and HR were derivedfrom the pulsat ile signal of the BP wa veform. A polyethylenetube w as inserted into th e left ventricle (LV) through the leftcommon car otid a rtery to mea sure LVP ; dP /d t w a s obt a inedby processing the pressure signal w ith a d erivat ive amplifier.

A midline laparotomy permitted exposure of the gallblad-der. During s urgica l procedures in t he ches t or bra in, t hea b d om i na l w a l l w a s cl os ed a g a i n w i t h a cl ip t o m a i n t a i n

mois t ure in t he a bdomina l ca vit y a nd t o prevent hea t los s .The a bdomen w a s opened a ga in only w hen B K or s a line w a sapplied to the gallbladd er.

Protocol 1

I n 1 2 ca t s , a m e d ia n or n e a r -m i d li n e s t e r not o m y w a sperformed. The perica rdium w a s incis ed ca refully a nd s u-t u r e d t o t h e ch e st w a l l t o e x pos e t h e h e a r t a n d a n t e r i orcorona ry a r t ery. A s ma ll , high dia gona l bra nch of t he lef tan terior descending coronary ar tery (LAD) on the ant erior LVw a ll w a s ident ified, a nd a 6-0 s urgica l s i lk s ut ure w a s pa s s edbelow t he vessel for subsequent ligat ion. A crysta l tra nsducerof the single-crystal sonomicrometer system (31) was fixed

w it h t is s ue a dhes ive (3M , Neus s , G erma ny) t o t h e a nt eriorwa ll of the LV in the region supplied by the dia gonal bra nch oft he L A D. R egiona l L V w a ll mot ion w a s mea s ured pre- a ndp os t l ig a t i on u s in g t h e s on om i cr om e t er s y s t em . C a r e w a sta ken to prevent dr ying of the exposed ant erior surfa ce of theheart by covering it wit h a saline-moistened gauze. Techni-ca lly s a t is fa ct ory w a ll mot ion da t a w ere obt a ined in 9 of t he12 animals.

Protocol 2

I n 23 ca t s (n 14 experimenta l, n 9 vehicle control), acra niot omy w a s performed t o expos e t he vent ra l s urfa ce ofthe medulla for microinjection. In these a nima ls, to minimizethe trauma of surgery, a sternotomy was not performed. Thet ra chea a nd es opha gus w ere ret ra ct ed, a nd t he prevert ebra lmuscles were removed from the ba sal pla te of the skull. Theba s ioccipit a l bone w a s ca refully removed from t he a t la nt o-occipit a l membra ne w it h rongeurs , a nd t he cra niot omy w a sextended for 4 m m o n e a c h s i d e o f t h e m i d l i n e o v e r t h emedullary surface. The dura then w as cut, a nd th e cerebrospi-na l fluid w a s removed, expos ing t he s urfa ce of t h e medulla .War m pa raffin oil wa s used t o cover the exposed medulla rysurface to prevent d esiccation. The an imals head w as fi xed in

a stereotaxic fra me (model J W-1C, S econd Military MedicalU nivers it y, S ha ngha i, P R C) t o a l low microinject ions t o bema de into the rVLM.

Acupuncture needles (Suzhou Acupuncture Medical Appli-a nce, Suzhou, P R C) w ere ins ert ed a t t he Neigua n a cupointov er l y in g t h e m e d ia n n e r ve t o a d e pt h of 5 10 m m . Anelect r ica l s t imula t or w it h a s t imulus is ola t ion unit (modelJ L-B, S ha ngha i J ialong Teaching Inst rument F actory, Sha ng-ha i, PRC ) provided current t o the needles. Correct positioningw a s c on fi r m e d b y ob s er v in g s l ig h t r e pe t it i v e p a w fl e x ionduring stimulation.

Chemicals

B K (Sigma , St . L ouis , M O) w a s dis s olved in norma l s a lineat room t emperatur e to a n init ial concentr at ion of 2.5 mg/ml.Appropria t e s eria l dilut ions w ere ma de t o obt a in des iredconcentra tions. The concentra tion of the fi na l solution of B Kwa s 10 g/ml, because this w as the lowest concentra tion tha tconsistently yields maximal cardiovascular responses whenapplied to th e ga llbladder (30). The stock solution of B K wa sstored in a freezer and wa s used for no more than 2 wk beforea fresh stock solution wa s prepared. Na loxone hydrochloride(Sigma) also was dissolved in normal saline. The concentra-tion w as 0.4 mg/ml for intra venous injection or 10 nM formicroinjection int o the P G L of the rVLM.

M icroinj ecti on Technique

For bilateral microinjection into the rVLM, stainless steelguiding tubes [outside diameter (OD) 0.46 mm, int erna l

dia met er (I D) 0.27 mm] were positioned at the surface ofthe medulla at a point overlying the PG L, as indicated by axiscoordina t es (2. 53. 5 mm la t era l t o t he midline, 0. 51 mmbelow t he vent ra l s urfa ce of t he medulla , a nd 0. 5- 1. 5 mmcaudal to the trapezoid border) (11, 24). An injection cannula(OD 0 .2 3 m m , I D 0.11 mm) connected to a 0.5-lmicrosyringe (model W-101, Sha ngha i Medical La ser In stru-ment Fa ct ory, Sha ngha i, P R C) w it h a polyet hylene ca t het er(P E-10) t hen w a s low ered t hrough t he guiding t ubes . Thei n je ct i on ca n n u l a s e xt e n d ed 1. 0 m m b ey on d t h e g u id i n gt ubes . The volume of inject ion (100 nl for ea ch s it e) w a sadministered in 1 min. After injections were completed, theca n n u l a w a s a l w a y s a l low e d t o r e m a i n i n t h e b r a i n f o r 4 5

H2128 NALOXONE REVERSES INHIBITORY EFFECT OF ELECTROACUPUNCTURE


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min t o prevent pos s ible ba ckflow of t he s olut ion a long t heinjection tra ck.

Histology

At th e end of ea ch microinjection experiment , 0.1 l of 0.5%pontamine sky blue was applied to each injection site. Aftert he a nima l w a s killed, t he bra in s t em w a s removed a nd fi xedin 10%Forma lin. Frozen seria l sections (50 m) of the br ain

were cut with a freezing microtome (model CM1900-Kryostat,L e ic a , We t z la r , G e r m a n y ). Th e s li ce s w e r e s t a i n ed w i t hneut ra l red, a nd t he inject ion s it e w a s ident ified by micro-scopic examina tion.

Protocols

A minimum of 1 h for s t a bil iza t ion of t he prepa ra t ion w a sallowed before observat ions w ere begun. B K (10 g/ml) wa sa p p li ed o nt o t h e s er os a l s u r fa c e o f t h e g a l l bl a d d er w i t h a1-cm 2 pledget of fil t er pa per s oa ked in t he s olut ion of B K.Aft er ma xima l ca rdiova s cula r res ponses w ere evoked, t hefilt er pa per w a s removed a nd t he ga llbla dder w a s w a s hed a tleast thr ee times w ith sa line-immersed cotton-tipped applica-t ors t o remove exces s B K. A s ignifica nt reflex res pons e w a sconsidered to ha ve occurred if BP increased 10 mmH g (26).

The avera ge increase in mean B P w as 40 5 mmHg a f t er t heapplication of BK . To prevent ta chyphylaxis t o BK , recoveryperiods of at least 15 min were provided after each applica-t ion of B K; t his procedure a llow ed cons is t ent , repea t a bleresponses. As a control for the vehicle, it was demonstratedthat cold saline did not evoke any cardiovascular responseswh en applied to the gallbladd er.

Protocol 1. After repeata ble baseline responses to B K w erer e c o r d e d , a s m a l l b r a n c h o f t h e L A D w a s l i g a t e d a n d t w oa ddit iona l a pplica t ions of B K w ere performed during a 30-min period. B ila t era l EA a t t he Neigua n a cupoint (media nnerve) was then applied (25 V, 0.5-ms pulse dura tion, an d 4Hz) for 30 min. During this period, repeated cardiovascularresponses to BK w ere induced at 10 an d 25 min. After EA wa st e r m in a t e d f or 5 10 m i n , n a l ox on e w a s a d m i n i st e r ed b y

int ra venous injection (0.4 mg/kg). Subseq uent ly, card iovascu-la r res pons es t o B K w ere induced a t lea s t t w ice a t 15-mininterva ls. Using a similar protocol, our laborat ory previouslyha s s how n (18) in t ime-cont rol a nima ls t ha t t he inhibit oryeffect of EA-like stimulat ion at the Neigua n a cupoint persistsfor at least 1 h.

Protocol 2. A prot ocol s imila r t o t ha t of protocol 1 w a sfollowed except that the chest was not opened and ischemiawas not induced. In this preparation, the coronary artery wasn ot l ig a t e d a n d w a l l m o t ion w a s n ot a s s es s ed . I n s t e a d , B Pw a s u s e d a s t h e m e a s u r e o f t h e r e fl e x c a r d i o v a s c u l a r r e -sponse. After EA had been stopped for 510 min, naloxonewas administered by bilateral microinjection (10 nM in 0.1 l)into the r VLM. In vehicle control a nima ls, the sa me protocola s pr otocol 1 w a s us ed except t ha t norma l s a line ra t her t ha nna loxone wa s m icroinjected.

Dat a M easur ement

Sy stem ic B P, MAP, HR, LVP, LV dP/d t, an d LV wa ll motionw ere recorded on a n eight -cha nnel polygra ph (model R M -6000, Nihon Kohden, Tokyo, J a pa n) a nd s imult a neous lyinput into a computer (Pentium-133, IBM) in some experi-ment s . Sys t olic B P (SB P ), dia s t olic B P (DB P ), a nd ma xima ldP /d t were calculated from recorded data. From regional LVwa ll motion, systolic wa ll thickening w as ca lculat ed as WTh 100 [(ESD EDD )/EDD ], w here ESD is end-s ys t olicdimens ion, ca lcula t ed from t he end of t he T w a ve or 20 msbefore peak dP /d t, a nd EDD is end-dia s t olic dimens ion,

calcula ted fr om the onset of dP/d t. Nor ma liz ed WTh (%WTh)w a s ca lcula t ed a s 100 [(maximum WTh response to BK pre-B K WTh)/pre-B K WTh] (18). Da ta w ere collected a ftereach a pplication of BK : baseline (typically 23 a pplications oruntil responses were consistent), twice during ligation pre-EA(protocol 1), tw ice during liga tion EA (or EA a lone, protocol2), a nd a t lea s t t w ice a f t er EA w a s s t opped.

Statistical AnalysisAll da t a a re pres ent ed a s m ea ns SE . The a ssumption of

norma l da t a dis t r ibut ion w a s a s s es s ed w it h t h e Kolmogorov-Smirnoff test . The Students paired t-t es t w it h a B onferronicorrect ion w a s us ed t o s t a t is t ica lly compa re my oca rdia l w a llt h i ck en i n g a t r e st a n d a t p ea k B K e ff ec t a t s ev er a l t i m epoints. Statistical comparisons among multiple groups werem a d e u s in g a r e pe a t e d -m e a s u r es a n a l y s is of v a r i a n c e(ANOVA). The St udent-Newm an -Keuls post hoc test wa sused to test the signifi cance of three preselected compar isonsin protocol 1: 1) l iga t ion vers us ba s eline, 2) ligation E Avers us l iga t ion, a nd 3) na loxone vers us l iga t ion E A. I nprotocol 2, the preselected comparisons were 1) E A vers usb a s el in e a n d 2) n a l ox on e (or s a l in e ) v e r su s E A. U n l e ssot herw is e s t a t ed, t he compa ris ons ut i l ized t he s econd B K

a p pl ica t i o n d u r in g e a ch m e a s u re m en t p er i od . Wh e n t h enormalit y t est fa iled, a r epeated-measur es ANOVA on ra nksfollowed by the S tudent -Newma n-Keuls method w as used forpairw ise multiple compar isons. P 0.05 w as consider ed to bes ignifica nt .

RESULTS

Effect of I ntr avenous N aloxone on EA Response(Pr otocol 1)

Basel i ne hemodynamic parameters. I n protocol 1a nima ls, baseline SB P, DBP, MAP, and H R w ere 159 7 mmHg, 87 6 mmH g, 110 6 m m Hg , a n d 181 9b eat s/m in , re spe ctively. Co ron ar y l ig at ion , EA , an d

intravenous naloxone did not significantly affect theser es t i n g p a r a m et e r s (P 0.05) e xce pt for a sm all ,s t a t i s t i ca l l y s i gn i fi ca n t (P 0.05) reduction in HRduring ischemia (172 8 bea t s/mi n).

Pressor response evoked by BK on gallbladder. Th eapplica tion of B K t o the serosa l surface of the ga llbla d-der resulted in pronounced a ctivat ion of th e cardiovas-cula r syst em. This wa s chara cterized by ma rked eleva-tion of B P (Fig. 1), LVP, a nd dP /d t (d ata n o t sh o wn ).Af t er cor on a r y a r t e r y l ig a t i on , t h e h em od y n a m i cchanges evoked by BK were not significa ntly decreased(e xce p t fo r S B P), su g g e stin g th at l ig at io n o f a sm allb r a n ch of t h e L AD d oe s n o t s ig n ifi c a n t l y a f fe ct t h ecard io vascu lar re sp o n se s e vo k e d b y B K (F ig . 2) . EA

significantly reduced the reflex pressor response, par-ticularly a fter 25 min (Fig. 2). The refl ex increases inS B P a n d D B P d u r i n g i s c h e m i a ( 3 2 5 a n d 28 6m m Hg , re spe ctively) w e re sig n ifi can tly d e cre ase d b yEA (19 3 a n d 12 2 mmHg, respectively). Reflexin cre ase s in HR we re sm all an d we re n o t af fe cte d b yischemia or E A.

Te n m in u tes af te r th e ad m in istra t ion of n alo xon eintravenously, the hemodynamic changes evoked by BKincreased; a fter 25 min, t he B K-induced increments ofSBP, DBP, and MAP were significantly increased com-p are d with p re-n alo xon e valu e s (F ig . 2), su g g estin g

H2129NALOXONE REVERSES INHIBITORY EFFECT OF ELECTROACUPUNCTURE


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th a t th e in h ib i tory e ffect o f E A on th e card iovascu larresponses evoked by B K could be reversed by a n opioidan tag o n ist .

Regional ventricular function. At baseline, the appli-cation o f B K to th e g a l lb lad d er sig n ifi can tly (P 0.05)increa sed WTh fr om its 11 1.1%resting v a lue to 14 1.4%(Fig. 3). After ligation of the diagonal branch ofth e coron ar y art e ry, re st in g WTh (11 1.1%) w a suncha nged, but %WTh du ring th e pressor response toB K decreased mar kedly to 32 6.2%(P 0.05). Aft er

E A, %WTh increa sed signifi cant ly t o 19 20%(rest-ing WTh 8.0 1.1%). In tr a venous na loxone signifi -cant ly reversed the regiona l contr a ctile response to B K(13 29%).

Effect of rV L M N aloxone on E A Response (Protocol 2)

Baseli ne hemodynam ic pa ram eter s. I n 14 cats , re st-i n g S B P , D B P , M A P , a n d H R w e r e 1 5 7 12 m m Hg ,89 8 mmH g, 114 9 mmHg, a nd 183 8 bea ts /min ,respectively. EA an d m icroinjection of n a loxone did notaffect these parameters (P 0.05). The ba seline h emo-dyna mic para meters in this group genera lly were simi-

lar to those observed in the group receiving naloxoneintravenously.

Pr essor r esponse evoked by BK on gall blad der. I ncompar ison w ith t he intra venous na loxone group, th isgroup showed similar activation of the cardiovascularsyste m wh e n B K w as ap p lied to th e g al lb lad d er. I n th e25th minute of EA, all hemodynamic changes evokedby BK w ere significan tly decrea sed in compar ison wit h

control (Fig. 4). Reflex-induced increments of SBP andDB P d ecreased from cont rol (45 7 and 38 6 m m Hg ,respectively) t o 22 6 and 23 6 mmH g, respectively,during EA. Microinjection of na loxone bila tera lly int oth e P G L of th e rV L M d id n ot ch an g e re st in g h e m od y-n am ic p ara m e ters, wh e re as th e ch an g e s in S B P, D B P,and MAP induced by BK at 5 min after microinjectionwere significantly larger than the increments observedbefore na loxone. Refl ex increases in SBP a nd DB P w ere37 6 and 32 6 mmHg, respectively, after naloxone(P 0.05). I n com p arison , sal in e con tro l an im a lsshowed no cha nge in MAP a t t he time point correspond-ing t o na loxone injection (Fig. 4).

M icroin jection sites. Examination of the brain slicesrevealed that all of the injection sites were within theP G L of the rVLM (Fig. 5).

DISCUSSION

This is the first study t o show tha t na loxone, adminis-tered intravenously or microinjected into the rVLM,significan tly reverses t he inhibitory effect of E A on t here fle x in cre ase in arte rial B P af te r th e ap p licat io n o fB K to t h e g a l lblad d e r. N aloxon e a lso exacerb at e d re -g ion al card iac d ysfu n ction asso ciate d with im b alan ce

Fig. 1. Computer-captured recordings of reflex increases in a rterial

blood pr essure (AP ; A ) and myocardia l wa ll thickening (B a n d C). Atpoints indicated by arrows, a pledget soaked in bradykinin (BK; 10g /m l) w a s a p p lied t o t h e s er osa l s u r fa c e of t h e g a l lbla d d er : a,baseline control measurement; b, a s m a l l b r a n c h of le f t a n t e r iordescending coronary artery (LAD) was ligated and response to BKwa s examined after 30 min; c, electroa cupuncture (EA; 0.5 ms, 4 Hz)was applied at Neiguan acupoint in foreleg for 30 min and BK wasapplied a t 25 min; d, na loxone was administered intra venously (0.4mg/kg) after 510 min a nd response to BK wa s measured 25 minlater. Fa ll in normalized w all thickening (%WTh) associat ed w ithreflexly increased sympathetic s t imulat ion in presence of LAD liga-t ion (b) w a s r e v er s e d b y E A (c). A decline in AP response a lso wa sa p p a r e n t (c). I n t r a v e n ou s a d m in is t r a t ion of t h e opioid a n t a g on is tnaloxone blocked effects of EA; wall thickening declined, and APr e s p on s e r e t u r n e d t o n or m a l (d). We ha ve shown previously th atsympathoinhibitory effects of EA at Neiguan persist for a t least 1 h(18). Therefore, na loxone wa s admin istered at a time wh en sympat ho-

inhibition by E A would be expected to ma inta in improved %WTh a nddiminished AP response to BK.

Fig. 2. Effects of corona ry ischemia (Isc), EA, an d na loxone (Nal) onmean art erial blood pressure (MAP) chan ges produced by BK . Afterr e pe a t a b le c on t r ol (Con ) r e sp on s e s t o B K w e r e obt a in e d , a s m a llbranch of LAD was t ied. BK applied to the gallbladder produced anonsignificant reduction in blood pressure response. Bila t eral E A for25 min produced a s ignificant reduction of pressor response, wh ichwa s reversed by na loxone (0.4 mg/kg iv). Da ta ar e means S E ; n10. * P 0.05.



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between myocardia l oxygen supply a nd dema nd. Thesed at a su pp ort ou r h yp oth e sis th a t th e e f fe cts of E A inthis model are mediated by opioids, specifically thosereleased in the rVLM.

In tr a ditional Chinese medicine, EA ha s been used totr eat a w ide ra nge of disea ses and disorders, including

hypertension, a ngina pectoris, myocardia l infar ction,a n d ca r d i a c a r r h y t h m i a s (2, 8, 10, 33, 38). An i m a le xp e rim e n ts h ave co n fi rm e d th at EA h as th e rap e u ticeffects in hypertension, hypotension, and myocardialisch e m ia (19). F o r e xam p le, s t im u lation of som at ica fferents in th e sciat ic nerve to mimic EA depresses BPin n on an e sth e tiz ed sp on ta n e ou sly h yp erte n sive rat s(45) and inhibits t he periaq ueducta l gr a y-evoked pres-s or r e sp on s e (25). I n t h e p r es en t s t u d y, w e f ou n dinhibitory effects of EA on t he r eflex pressor r esponseinduced by t he a pplica tion of B K t o the gallbladder in a

ma nner similar t o the long-last ing sympat hoinhibitoryresponse to EA described by Lovick et a l. (25). P reviouswork by one member of our gr oup (15) has shown t ha tE A i n n or m ot e n si ve r a b b it s a c t i va t es a s y m pa t h et i cinhibitory pat hw a y in the brain, including the ar cuatus

Fig. 3. A : e ff ec t of E A on r e g ion a l s y s t ol icWTh of left ventricle. A small branch of LADw a s l iga t e d , a n d d e m a n d -in d u ce d is ch e m iawas provoked by application of BK to gallblad-der to elicit a sympa thetic response. Da ta arem e a n s S E ; n 9. * P 0.05, rest vs. peakB K r e sp on s e. B: %WTh a t 4 t im e p oin t s

shown in A . Signifi cant decline in w all motionduring ischemia w as signifi cantly reversed byEA . A d m in is t r a t ion of N a l (0 .4 m g /k g iv )s ig n ifi c a n t ly r e d u c e d e f f e c t of EA . D a t a a r em e a n s S E . * P 0.05, Isc vs . C on, EA vs.Isc, and Na l vs . EA.

Fig. 4. Compa rison of hemodyna mic effects of Nal (0 nM in 0.1 l; n1 4) a n d n or m a l s a l i n e ( 0. 1 l ; n 9) microinjected int o rostralv e n t r ola t e r a l m e d ulla a f t e r EA . EA s ig n ifi c a n t ly r e d uc ed r e fle xpressor response to BK applied to gallbladder. Nal administrat ionsignificantly blocked effect of EA, which was not a ltered by vehicle(saline), indicat ing a persistent effect of EA on blood pressure tha tcould be blocked, in part , by Nal. Data (means S E) f or N a l a n ds a l in e in j e c t ion s w e r e ob t a in e d 5 m in a f t e r a d m in is t r a t ion . * P 0.05, EAvs. C on and Na l vs . EA.

Fig. 5. Outline drawings of sect ions of ventral medulla illustrat ingsites of microinjection of na loxone. Sectional an at omy wa s taken fromthe a t las of Berma n (4). Nos. indicat e distance (in mm ) rostra l fromobex; r, naloxone injection sites; s, control (saline) injection sites.ION, nucleus of inferior olive; RFN, retrofa cial nucleus; P T, pyra mi-d a l t r a c t ; 5 S P , a la m in a r s p in a l t r ig e m in a l n u c le u s , p a r v oc e l lu la rdivision.



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n u cle u s in th e h yp o th alam u s, th e ve n tral p o rt io n o fp er i a cq u ed u ct a l g r a y m a t t er, a n d t h e n u cl eu s r a p h eob s cu r u s. We p os t u la t e d i n t h e p r es en t s t u d y t h a ta c t i va t i on of t h i s s y s t em w o ul d i n hi bi t s y m pa t h et i cn e u ron s in t h e P G L of th e rV L M , an im porta n t cen te rfor th e int egra tion of car diovascula r reflexes (3, 36) a ndth e so u rce o f sp in al sym p ath e tic o utfl ow th ro u gh th eint erm ediola ter a l cell column (1, 23, 34). The inhib it oryp ath w ay can b e act ivat e d by st im u latin g fi n e ly m ye lin -a ted a nd nonmyelina ted somat ic afferent fi bers excitedby EA or acupuncture-like stimulation (18). The pre-s en t r es u lt s d em on s t r a t e t h a t t h e r e fl e x s y m p a t h e t icresponse during stimula tion of the ga llbla dder is inhib-ited by an opioid-related mechanism in the PGL of therVLM during EA of Neigua n.

Th e a p plicat ion of B K to t h e se rosal su rface of t h ega llbla dder evokes a signifi cant , sympat hetically medi-a t e d c a r d i o v a s c u l a r r e fl e x r e s p o n s e , a s w e h a v e r e -port ed previously (18, 26, 30). Regiona l LV w a ll motion,as assessed by a single-crystal sonomicrometer (31), isincreased by t he B K-induced r eflex response. Ligat ion

of a sm a ll bran ch of the LAD supplying this region doesn o t s ig n ifi can tly al te r re st in g wall m o tio n , b u t re fle xactivation of the cardiovascular system by the applica-t i on of B K t o t h e g a l lb la d d e r p r od u ce d s ig n ifi c a n tischemia-induced wall motion dysfunction. The reduc-tion of regional syst olic wa ll thickening is t he result oft h e a u g m e n t e d m y o c a r d i a l o x y g e n d e m a n d , a s i n d i -ca t e d b y s ig n ifi c a n t i ncr ea s es i n B P a n d H R (16),asso ciate d with re fle x sym p ath e tic act ivat io n , in th esetting of limited coronary blood flow (18). The result-in g im b alan ce o f th e o xyg e n su p p ly- to - d e m an d rat ioi n d u ce s r e gi on a l m y oc a r d i a l i s ch e m ia a n d , con s e-quently, impaired regional contractile function. How-ever, EA a t the Neiguan a cupoint signifi cant ly reduces

myoca rdial ischemia a nd improves regiona l myoca rdia ldysfunction, as indicated by the significant increase inw a l l t h ick en in g. Th is fi n d in g s ug ges t s t h a t E A a tN e ig u an cau se d m yocytes in th e isch e m ic re g ion toresume near-normal contractile function. Our previousstudy (18) indica ted th a t t his restorat ive effect is due tothe reduction in my oca rdia l oxygen deman d seconda ryto inhibition of th e reflex pressor response to B K, ra th ertha n a n increase in coronary blood fl ow.

Th e m od e l of sym p ath e tical ly p rovok ed isch e m icdysfunction ut ilized in t he present study is of interestb ecau se card iac p atie n ts with l im ite d coron ar y b loodflow secondary to coronary atherosclerosis report an-gina pectoris in a ssociat ion w ith exercise or emotional

stre ss, act ivi t ie s th at au g m e n t sym p ath e tic to n e (35,40). I t is possible, therefore, that EA or acupuncturema y be a useful thera peutic approa ch for the treat mentof a ngina in some patients. In t his regard, success wit hth is ap p roach h as b ee n re porte d (2, 33). Ad d it ion alcontr olled clinica l investiga tions ar e wa rra nted t o va li-d at e th is p ote n tial ly b e n efi cial an d in expe n sive tre at -ment m oda lity.

We observed t ha t intra venous injection of n a loxonere verse d th e in h ib i tory e ffect of EA o n th e p ressorresponse and resulting regional wall dysfunction pro-d u ce d b y t h e a p p li ca t i on of B K on t h e g a l lb la d d e r.

These results suggest that endogenous opioids, likelyreleased in the CNS, mediate this inhibitory effect ofEA. It ha s been reported th a t -endorphins a re presentin t he ventra l medulla (9). Fur thermore, local a pplica -tion of naloxone on the S area (before the root of the12t h cr a n ia l n er v e a n d l a t er a l t o py r a m id ) of t h eve n tral su rface o f th e m e d u lla re ve rse s th e salu taryeffect of EA at the Neiguan acupoint on acute ischemicmyoca rdia l injury in r a bbits induced by 20-min occlu-sion of th e LAD (13). These st udies support a s ym pa th o-inhibitory role of endogenous opioids released in therVLM.

Opioid-receptor subtypes t ha t contr ibute t o t he cen-tral act io n o f EA are u n k n o wn ; h o we ve r, - , - , an d-re ce pto rs e ach p ote n tial ly cou ld m e d iat e th is re -sp on se. Ot h e r t ra n sm itte rs a lso m ay b e in volved . F o rin stan ce , th e im p ro ve m e n ts o f L V p re ssu re an d S - Tsegment depression produced by E A in a ra bbit modelof myocardial ischemia were inhibited by microinjec-tion of yohim bine int o the r VLM (20). Thus 2-receptorsin th e rV L M also m ay b e in vo lve d in th e in h ib i to ry

effect of E A. Additional studies a re necessa ry to iden-tify th e individua l cont ribut ions of opioid-receptor s ub-types and interactions with other mediators during EAof Neiguan.

Although microinjection of naloxone into the rVLMsignifican tly reversed the effect of EA on the art erial B Presponse to BK (Fig. 4), it did not completely r estore th eresponse. This part ial reversal m a y be related, a t leastin part , to the par ticipa tion of other r egions of the bra inin th e in h ib i to ry p ath way. I t h as b e e n su g g e ste d th atthe nucleus arcuatus, ventral periaqueductal gray, andn u cle u s rap h e o b scu ru s p lay a ro le in th e in h ib i to ryeffect of deep peroneal nerve st imula tion on th e defensereaction induced by stimula tion of the hy potha lam ic or

m id b rain d e fe n se are as (17). F u rth e r stu d ie s wil l b enecessary to determine whether these regions also areinvolved in the inhibitory effect of EA at the Neiguana cupoint on th e gallbla dder-induced pressor refl ex.

The Neiguan acupoint was selected because it is oneof the primary acupoints used clinically in traditionalChinese medicine to trea t coronary heart disease (2, 8,19). I t also is an acupoint commonly utilized to studythe effects of EA in severa l different a nima l models ofcardiovascular disease (13, 18, 19). P revious prelimi-n ary stu d ie s (19) h ave su g g e ste d th at s t im u latio n o fnerves underlying other acupoints can elicit differente f fe cts o n arte rial B P, b u t ad d it io n al s tu d ie s are re -quired to address fully the issue of acupoint specificity.

There are three potential l imitations of the presentstudy. First, the use of intravenous naloxone does notallow identification of the neurological site(s) of opioidinhibition. How ever, this sh ortcoming wa s overcome byad ministering na loxone locally into a specifi c region ofthe m edulla , t he P G L of the r VLM. Localized injectionallowed identification of the neurological locus of theopioid-mediated inhibition evoked by EA.

Second, corr ect positioning of a cupuncture needles inpat ients relies on feedback from the pa tient t o identifythe onset of a feeling of heaviness associat ed w ithe le ctrical s t im u lat ion of th e n e ed les wh e n th e y are



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properly positioned at the acupoint (43, 44). Becauset h i s i n f o r m a t i o n i s n o t a v a i l a b l e i n a n a n e s t h e t i z e da nima l prepara tion, our criterion for correct tra nscuta -neous insertion of the acupuncture needles relied onour observation of a slight repetitive flexion of the pawd u rin g e le ctrical s t im u lation . I n ou r p reviou s stu d y(18), in which the median nerves underlying the Nei-g u an acu p oin t we re e xp ose d a n d st im u late d d irectly,

th e sa m e cri te rion w as u sed t o esta b l ish a sat isfacto rylevel of electrica l stim ula tion. The simila r effects on B Pof EA a t t he Neiguan a cupoint in t he present study, an dof direct electrical stimula tion of the media n nerves inthe previous study (18), support the postulated role ofst im u lation o f th e m e d ian n e rve a s t h e tr ig g e r e ven t .Moreover, the similar modification of the gallbladder-induced reflex hemodynamic responses during directst im u latio n o f th e m e d ian n e rve (18) an d EA o f th eN e ig u an acu p oin t u sin g a tra n scu ta n e ou s a p proachsupport s th e genera l concept tha t t he effects of acupunc-ture and EAare the result of stimulation of underlyingnerves, particularly group III and IV somatic afferents(18, 21).

T h e th ird p o te n tial l im itat io n is th at n alo xo n e d idnot completely in hibit th e EA-indu ced effect. This couldb e c a u s e d b y 1) insufficient na loxone a nd thereforeinsufficient blocka de, 2) o t h e r a r e a s t h a t m i g h t s t i l lmediat e the response, and 3) other potentia l mediat orstha t might be importa nt in this response.

In conclusion, the new fi nding in this study is tha t E Aat the Neiguan acupoint inhibits a gallbladder-evokedpressor response by a n opioid-rela ted mecha nism in t heP G L of t h e r VL M . N a l ox on e a d m in i st r a t i on a l s o r e -versed the EA-induced improvement in regional ische-mic myoca rdia l dysfunction. The similar hemodyna miceffects produced by transcutaneous EAat Neiguan anddirect stimula tion of median nerves support t he notionth a t local iz ed st im u lation p rod u ce d b y acu pu n ctu rea nd EA a t specific a cupoints exerts a n effect in t he CNSby stimulation of somatic afferent nerves that, at leastin some insta nces, underlie the a cupoint a long a tra di-tional Chinese meridia n.

We gra tefully a cknowledge the extra ordinary technical a nd edito-rial assistance of Stephen Rendig and the secretarial assistance ofJ ill Woodar d.

This work w as supported by Nat ional Nat ural Science Foundat ionof Ch in a G r a n t N o. 3 9 6 1 0 1 2 0 9 5 5 a n d N a t ion a l H e a r t , L u n g , a n dB lood In stitu te G ra nts HL -36527, HL-52165, and H L-07682.

Ad d r es s f or r e pr in t r e q u es t s a n d ot h er c or r e s pon de n ce : J . C .Longhurst , Dept . of Medicine, Un iv. of C alifornia , I r vine, CA 92868(E-mail: [email protected]).

Received 20 August 1998; accepted in fi na l form 2 Ma rch 1999.

REFERENCES

1. Amendt, K., J . Czachurski, K. Dembowsky, and H. Seller.Bulbospinal project ions to the intermediolatera l cell column: aneuroanat omical s tudy. J . Auton. N erv. Syst. 1: 103117, 1979.

2. Bao, Y. X., H. H. Lu, G. R. Yu, D. S.Zheng, B. H. Cheng, andC. C. Pan. The immediate effect on acute myocardial infarctiontreated by puncturing Neiguan. Chin. Acupunct. Moxib. 1: 25,1981.

3. Bauer, R. M., G. A. Iwamoto, and T. G. Waldrop. Ventrolat-e r a l m e d ulla r y n e u r on s m od ula t e p r es s or r e fle x t o m u s cu la rcontraction. Am. J. Physiol . 257 (Regulatory In tegrat ive Comp.Physiol. 26): R1154R1161, 1989.

4. Berman, A. L. The Br ain Stem of the Cat: A Cytoarchi t ectonicAt las wit h Stereotaxic Coordinates. Ma dison, WI: U niv. of Wiscon-sin P ress, 1968.

5. Breyfogle, H. S. The frequency of coexist ing gallbladder andcoronary disease. J A M A 114: 14341437, 1940.

6. Caringi, D., D. J . Mokler,D. M.K oester,andA. Ally. R os t r a lventrolateral medullary opioid r eceptor act ivat ion modulatespressor response to muscle contra ct ion. Am . J. Physi o l . 274(Heart Circ. Physiol. 43): H139H 146, 1998.

7. Chao, D. M., Y. X.Cao,K. F.Pitsillides, J . C. Longhurst,andP.Li. Role of opioids in th e inhibitory effect of acupuncture on th egallbladder pressor response (Abstra ct). F A S E B J . 12: A690,1998.

8. Chen, S. Z. The comparat ive observat ions on the effects ofpuncturing J ianshi and Neiguan on the left cardiac function ofp a t ien t s w i t h c or on a r y d is ea s e . Cl i n. J . Acupunct . M oxi b . 10:3032, 1994.

9. Finley, J . C. W., P. Lindstrom, and P. Petrusz. Immunocyto-chemical localization of -endorphin-containing neurons in ther a t b r a in . Neuroendocrinology33: 2842, 1981.

10. Gao, Z. W., X. Z. Yu, A. X. Shen, L. E. Bao, and X. C. Ling.Clin ic a l ob s er v a t ion on t r e a t m e n t of 2 20 c a s e s of a r r h y t h m iawith acupuncture. In: Compi lat i on of th e Abstracts of Acupunc- t ur e and M oxi bust i on Paper s. T he Fi r st Wor l d Congr ess onAcupuncture-Moxibustion. Ha ngzhou, PRC : World Federat ion ofAcupuncture a nd Moxibustion St udies, 1987, p. 1314.

11. Gatti, P. J ., W. P. Norman, A. M. T.Dasilva, and R. A. Gillis.Cardiorespiratory effects produced by microinjecting L-glutamicacid into medullary nuclei associated w ith t he ventral surface ofthe feline medulla. Br ain Res. 381: 281288, 1986.

12. Holaday, J . W. Ca rdiovascular effects of endogenous opiatesystems. Ann u. Rev. Phar macol. Toxicol. 23: 541594, 1983.

13. Huang, E. M., Q. Z. Feng, and P. Hu. Role of ventrolateralmedulla ry a rea in the effect of electrica l needling Neiguan pointon improving acute myocardial ischemia in rabbits . Acupunct.Res. 16: 108111, 1991.

14. Huangfu, D. H., and P. Li. The inhibitory effect of the deepperoneal nerve input on the ventral medullary defense-reaction-related neurons. Chi n. J. Physiol. Sci. 2: 123131, 1986.

15. Huangfu, D. H., and P. Li. The inhibitory effect of ARC-PAG-N R O s y s t e m on t h e v e n t r ola t e r a l m e d u lla r y n e u r on s in t h er a b b i t . Chi n. J. Physiol. Sci. 4: 115125,1988.

16. Kitamura,K.,C. R. J orgensen,F.L .Gobel,H .L .Taylor,and

Y. Wang. Hemodynamic correlates of myocardial oxygen con-sumption during upright exercise. J. A ppl . Physiol . 32: 516522,1972.

17. Li, P. M od u la t or y e ff ec t of s om a t ic in p u t s on t h e m e d ulla r ycardiovascular neuronal function. News Physiol. Sci. 6: 6972,1991.

18. Li, P., K . F. Pitsillides, S. V. Rendig, H .-L. Pan, and J . C .Longhurst. Reversal of reflex-induced myocardia l ischemia bymedian nerve stimulation: a feline model of electroacupuncture.Circulat ion 97: 11861194, 1998.

19. Li, P., and T. Yao. M echani sm of t he M odul at or y Ef f ect of Acupuncture on Abnorm al Card iovascular F unct ions. S h a n g h a i ,PR C: Sha nghai Medical Univ. Press, 1992.

20. Liu,J . L.,S.P. Chen,Q.S. Cao,and J . J .Zhang. Infl uence ofmicroinjection of clonidine and yohimbine in rVLM on the effectof electroacupuncture treatment of myocardial ischemia. Acu-pun ct. Res. 21: 31 35, 1996.

21. Liu, R. T., and M.L ang. Effect of electrical needling Neiguan p oin t on t h e p r om ot ion of t h e r e cove r y of a c u t e m y oca r d ia lischemia in cats : analysis of a fferent pathways. Acupunct. Res.11: 229233, 1986.

22. Longhurst,J . C. Acupunctures beneficial effects on t he car dio-vascular system. Prevent iveCardiol . 4: 21 33, 1998.

23. Lovick, T. A. Descending project ions from the ventrolateralmedulla a nd cardiovascular control. Pflu ger s Ar ch . 404: 197202, 1985.

24. Lovick, T. A. D iff er e n t ia l c on t r ol of c a r d ia c a n d v a s om ot oract ivity by neurons in nucleus paragigan tocellularis la tera lis inthe cat . J. Physiol. (Lond.)389: 2335, 1987.

25. Lovick, T. A., P. Li, and L. C. Schenberg. Modulat ion of thecardiovascular defense response by low frequency stimulation of



9/9

a deep somatic nerve in rats . J. Auton. N erv. Syst . 50: 347354,1995.

26. Martin, S. E., D. M. Pilkington, and J . C. Longhurst.Coronary vascular r esponses to chemical s t imulat ion of abdomi-nal visceral organs. Am. J . Physiol . 256 (Heart Circ. Physiol. 25):H735H744, 1989.

27. McLemore, G. A., and S.A. Levine. The possible therapeuticvalue of cholecystectomy in Adams-Stokes disease. Am . J. M ed.Sci. 229: 396391, 1955.

28. Morilak, D. A., G. Drolet, and J . Chalmers. Cardiovasculare ff ec t s of op ioid a n t a g on is t n a loxon e in r ost r a l v e n t r ola t e r a lmedulla of rabbits . Am. J. Physiol . 258 (Regulatory Int egrat iveComp. Physiol. 27): R325R331, 1990.

29. Newman, P. P. Vi scer al Af f er ent Funct i ons of t he Ner vousSystem. London: E dwa rd Arnold, 1974, p. 3537.

30. Ordway, G. A., and J . C. Longhurst. Cardiovascular reflexesa r is in g f r om t h e g a l lbla d d er of t h e c a t . E f fe ct of c a p s a icin ,bradykinin, an d distension. Circ. Res. 52: 26 35, 1983.

31. Pitsillides, K. F., and J . C. Longhurst. An ultra sonic systemfor measurement of absolute myocardial thickness using a singletransducer. Am. J . Physiol . 268 (Heart Circ. Physiol. 37): H1358H1367, 1995.

32. Punnen, S., R. Willette, A. J . Krieger, and H. N. Sapru.Cardiovascular response to injections of enkephalin in the pres-s or a r e a of t h e v e n t r ola t e r a l m e d ulla . Neuropharmacology 23:939946, 1984.

33. Richter,A.,J . Herlitz, and A. Hjalmarson. Effect of acupunc-ture in pat ients wit h angina pectoris . Eur. Heart J. 12: 175178,1991.

34. Ross, C. A., D. A. Ruggiero, A. J on, D. H. Park, and D. J .Reiss. Rostral ventrolateral medulla: selective projections to thethoracic autonomic cell column from the region containing C1adrena line neurons. J. Comp. Neurol. 228: 168185, 1984.

35. Rozanski,A., C. N. Bairey, D. S.Krantz, J . Friedman,K. J .Resser, M. Morell,S. Hilton-Chalfen, L. Hestrin, J . Bieten-dorf, and D. S. Berman. M e n t a l s t r e s s a n d t h e in d u c t ion ofs i le n t m y oca r d ia l is ch e m ia in p a t ien t s w i t h c or on a r y a r t e r ydisease. N. En gl . J. Med. 318: 10051012, 1988.

36. Stornetta, R. L., S. F. Morrison, D. A. Ruggiero, and D. J .Reis. Neurons of rostral ventrolatera l medulla mediate somaticpressor reflex. Am. J . Physiol . 256 (Regulatory I ntegrat i veComp.Physiol. 25): R448R 462, 1989.

37. Sun, S. Y., Z.L iu, P. Li, and A. J . Ingenito. Central effects ofopioid agonists and naloxone on the blood pressure and heartrat e in normotensive and hypertensive rat s . Gen. Phar macol. 27:11871194, 1996.

38. Tam, K.-C., and H.-H. Yiu. The effect of a cupuncture onessential hypertension. Am. J. Chin . Med. 3: 369375, 1975.

39. Tennant, R., and H. M. Zimmerman. Association betw eend is ea s e in t h e g a l lb la d d er a n d in t h e h e a r t a s e v id e n ce d b yautopsy. Yale J. Bi ol . M ed. 3: 495 503, 1931.

40. Victor,R. G., D. R. Seals, and A.L . Mark. Differential controlof h e a r t r a t e a n d s y m p a t h e t ic n e r v e a c t iv i t y d u r in g d y n a m icexercise: insight from intr aneura l recordings in h umans. J. Cl i n .Invest. 79: 508516, 1987.

41. Wakefield, H. The associat ion of the gallbladder disease withheart disease. M ed. Cl in. North Am. 31: 161171, 1947.

42. Walker, K., M. Perkins, and A. Dray. K i n in s a n d k in i nreceptors in the nervous system. Neurochem. Int. 26: 1 16, 1995.

43. Wei-Ping, W. Chin ese Acupuncture. W h it s t a b le , U K : S t r a k e rBr others, 1962.

44. Weng, E. Q. P a i n a n d a n a l g e s i a . S h a n g h a i , P R C : S h a n g h a iScience a nd Technology, 1987, p. 182233.

45. Yao, T., S.Andersson,and P. Thoren.Long-last ing cardiovas-cular depression induced by acupuncture-like stimulation of thes cia t ic n e r v e in u n a n a e s t h e t ize d s p on t a n e ous ly h y p er t e n s iv er a t s . Br ain Res. 240: 7785, 1982.


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