Reviews of

130 PhysiologyBiochemistry andPharmacologyEditor s

M.P. Blaustein, Baltimore H. Grunicke, Innsbruck

D. Pette, Konstanz G . Schultz, Berlin

M. Schweiger, Berlin

Introduction 1

2

Somatic Sources of Afferent Inputto the Autonomic Nervous System 7

2 .1

Introduction 7

2 .2

Low-Threshold .Somatosensory Receptor 82 .2 .1 Cutaneous and Subcutaneous Low-Threshol d

Sensory Receptors 9

2 .2 .1 .1 Mechanoreceptors 9

2 .2 .1 .2 Thermoreceptors 1 82 .2 .2 Low-Threshold Sensory Receptors in Muscl e

and Tendon 212 .2 .2 .1 Muscle Spindles and Tendon Organs 2 12 .2 .2 .2 Noncorpuscular Low-Threshold Sensory Receptors

in Muscle and Tendon 242 .2 .3 Low-Threshold Sensory Receptor s

in Articular Tissue 27

2 .2 .3 .1 Response Propertie sof Group II Articular Afferents 27

2 .2 .3 .2 Response Properties of Low-Threshold Group II Iand IV Articular Afferents 29

2 .2.3 .3 Total Sensory Outflow at Res tand During Movement of Normal Joints 29

2 .3

Somatic Nociceptors2 .3 .1 Cutaneous and Subcutaneous Nociceptors 3 12 .3 .1 .1 Mechanonociceptors

(HTM-AS-Units and CM Units) 3 12 .3 .1 .2 Heat Nociceptors (CH Units) 3 22 .3 .1 .3 Polymodal Nociceptors (CMH and AMH Units) 3 22 .3 .1 .4 Unresponsive Cutaneous C Nociceptor s

(CMiHi Units) 3 32 .3 .1 .5 Experimental Activatio n

of Cutaneous Nociceptors 3 42 .3 .2 Nociceptors in Muscle and Tendon 3 42 .3 .2 .1 Localization and Structure of Muscl e

and Tendon Nociceptors 3 52 .3 .2 .2 Response Properties of Muscl e

and Tendon Nociceptors 3 52 .3 .3 Articular Nociceptors 3 82 .3 .3 .1 Fine Structure of Group III

and IV Articular Terminals 3 82 .3 .3 .2 Response Properties of Group II I

and IV Articular Nociceptors 4 02 .3 .4 Sensitization and Desensitization

of Somatic Nociceptors 4 32 .3 .4.1 General Aspects of Sensitization of Nociceptors 4 32 .3 .4.2 General Aspects of Desensitization

of Nociceptors 4 52 . 3 . 4.3 Special Aspects of the Sensitization of Cutaneous ,

Muscular, and Articular Nociceptors 4 82 .4

Composition of Somatic Nerves 5 42 .4 .1 Classification of Primary Somatic Afferen t

Nerve Fibers 5 42 .4 .2 Composition of Cutaneous Nerves 5 52 .4 .3 Composition of Muscle Nerves 5 72 .4 .4 Composition of Articular Nerves 5 82 .4 .5 Composition of Mixed Nerves ,

Spinal and Dorsal Roots 6 0

2 .4 .6 Special Aspects of Cranial Nerves 61

2 .4 .7 Activation of Primary Afferent Nerve Fiber sby Electrical Stimulation 62

2 .4 .7.1 Advantages and Disadvantage sof Electrical Stimulation of Primary Afferents 62

2 .4 .7.2 Effects of Preferential Blockin gof A and C Fibers 6 3

2 .5

Spinal and Brain Stem Terminatio nand Projection of Somatic Primary Afferents . 64

2 .5 .1 Termination and Projectionof Cutaneous Primary Afferents 64

2 .5 .2 Termination and Projectionof Muscle Primary Afferents 6 6

2 . 5 .3 Termination and Projectionof Articular Primary Afferents 6 8

2 .6

Summary and Conclusions 6 9

3

Central Processing(Pathways, Modes of Operation) 7 3

3 .1

Introduction 7 33 .2

Somato-sympathetic Reflexes 7 6

3 .2 .1 Sympathetic Reflex Responses to Stimulationof Myelinated (A) Somatic Afferents ;the A Reflexes 76

3 .2 .1 .1 Early Spinal, Late Supraspinal (or Medullary) ,and Very Late SuprapontineA reflex Components 7 6

3 .2 .1 .2 Inhibitory Somato-sympathetic Reflexes 8 73 .2 .2 Sympathetic Reflex Responses to Stimulation

of Unmyelinated (C) Somatic Afferents ,

the C Reflexes 9 13 .2 .2.1 Medullary Regions and Spinal Tract Involve d

in the Supraspinal C Reflexes 9 53 .2 .3 Convergence of Various Somato-sympatheti c

Reflex Pathways on Single Sympathetic Neurons 9 63 .2 .3 .1 Preganglionic Neurons 9 63 .2 .3 .2 Postganglionic Neurons 97

3 .2.4 Various Influence son Somato-sympathetic Reflexes 100

3 .2.4 .1 Modulation by Barorecepto rand Chemoreceptor Excitation 100

3 .2 .4 .2 Involvement of Opioid Receptors 100

3 .2 . 4.3 Involvement of Nitric Oxide 10 23 .2 . 4.4 Involvement of Glutamate Receptors 1043 .2 .4.5 Effects of Anesthesia 10 53 .3

Somato-parasympathetic Reflexes 10 73 .3 . 1 Cranial Parasympathetic Recording 1073 .3 .2 Sacral Parasympathetic Recording 10 83 .4

Visceral Regulatio nby Axon Reflex-Like Mechanisms Followin gSomatic Afferent Stimulation no

3 .5

Comparison of Somato-autonomi cand Somato-somatic Reflexes 11 1

3 .6

Conclusion 11 2

4

Organ Reactions to Somatosensory Input( "Somato-autonomic Reflexes " ) 11 5

4.1

Somatosensory Modulationof the Cardiovascular System 11 5

4.1 .1

Introduction 11 54 .1 .2 Somatosensory Modulation of Heart Rat e

and Blood Pressure 11 84 .1 .2.1 Cutaneous Stimulation 11 84 .1 .2 .2 Muscle Stimulation 1274 .1 .2 .3 Acupuncture-Like Stimulation 1 334 .1 .2 .4 Joint Stimulation 1 354 .1 .2 .5 Electrical Stimulation 1 3 94 .1 .2 .6 Central Processing of Somato-cardiac Reflexes 14 64.1 .3 Somatosensory Modulation of Blood Flow 1484.1.3 .1 Skin Blood Flow 1484.1 .3 .2 Muscle Blood Flow 15 04 .1 .3 .3 Cutaneous and Muscl e

Sympathetic Nerve Activity 152

4 . 1 .3 .4 Somatosensory Modulation of Blood Flowin the Genital Organs 153

4 .1 .3 .5 Somatosensory Modulationof Regional Cerebral Blood Flow 15 4

4 .1 .3 .6 Somatosensory Modulation of Blood Flowin the Peripheral Nerves 16 o

4 .1 .4 Conclusion 16 34 .2

Somatosensory Modulationof the Digestive System 16 6

4 .2 .1 Introduction 16 64 .2 .2 Somatosensory Modulatio n

of Gastrointestinal Motility 16 8

4 .2 .2.1 Gastric Motility 16 84 .2 .2.2 Intestinal Motility 17 54 .2 .3 Somatosensory Modulation

of Digestive Secretion 18 04 .2 .3 .1 Salivary Secretion 18 04 .2 .3 .2 Gastrointestinal Secretion 1824 .2 .4 Somatosensory Modulation

of Gastrointestinal Blood Flow 18 3

4 .2 .5 Central Processingof Somato-gastrointestinal Reflexes 18 4

4 .2 .5 .1 Somato-splanchnic Sympathetic Reflex 18 44 .2.5 .2 Somato-vagal Reflex 18 54 .2.6 Conclusion 18 6

4 .3

Somatosensory Modulationof the Urinary System 18 9

4 .3 . 1 Introduction 18 9

4 .3 .2 Cutaneous Stimulation 19 2

4 .3 .2 .1 Mechanical Stimulation 19 2

4.3 .2.2 Thermal Stimulation 1 9 94.3 .3 Muscle Stimulation 20 1

4.3 .4 Acupuncture-Like Stimulation 20 2

43 .5 Electrical Stimulation 20 3

43.6 Central Processing of Somato-vesical Reflexes 20 6

4.3 .7 Conclusion 21 1

4. 4

Somatosensory Modulationof the Sudomotor System 21 3

4.4 . 1 Introduction 213

4 .4 .2 Somatosensory Modulation of the Sweat Gland 21 5

4 .4 .3 Conclusion 219

4 .5

Somatosensory Modulationof I-Iormonal Secretion 219

4 .5 .1

Introduction 219

4 . 5 .2 Adrenal Medullary and Pancreatic Hormones 220

4 .5 .2 .1 Adrenal Medullary Hormones 22 1

4 .5 .2 .2 Pancreatic Hormones 236

4 .5 .3 Hypothalamo-anterio rPituitary Hormone System 23 9

4 .5 .3 .1 CRH-ACTH-Cortical Hormones 24 1

4 . 5 . 3 .2 Gonadotropin-Gonadal Sex Hormones 24 44 .5 .3 .3 Growth 1-Iormone 2464 .5 .3 .4 Prolactin 24 74 .5 .4 Posterior Pituitary Hormone System 24 8

4 .5 .4 .1 Oxytocin 24 94 .5 .4 .2 Väsopressin 25 1

4 .5 .5 Conclusion 25 1

4 .6

Somatosensory Modulationof the immune System 25 3

4 .6 .1

introduction 25 34 .6 .2 Cutaneous Stimulation 25 44 .6 .3 Conclusion 25 5

5

Concluding Remarks 25 7

Appendix : A Personal Note 2.63

References 265

Subject Index 307