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What are Psychoactive drugs? ____________________________________________________________________________________
PSYCHOACTIVE DRUGS
There are several classes of psychoactive drugs:
I. Sedative hypnotics and antianxiety drugs
Most common are: 1. _______ (everything that
contains ethyl alcohol).
2. _______________ (ex.,
pentobarbital).
3. ________________ (ex.,
valium, librium).
- they are also known as “_________________”.
substances that influence subjective experience and behavior by acting on the nervous system.
Alcohol
Barbiturates
Benzodiazepines
mild tranquilizers
Behavioral effects:
Characteristics of sedative-hypnotic drugs:
Tolerance: ______________________________________________________________________________________________________________________________________
decreased susceptibility to a drug that develops as a result of repeated exposure to the drug; compensatory mechanisms opposite to the initial drug effect Cross-tolerance: __________________________
_________________________________________
__________________________________
tolerance that develops to one
drug carries over to other drugs suggesting that
they act through the same target.
Target of sedative-hypnotic & antianxiety drugs:
_______________________________________GABA receptors (especially GABAA subtype)
II. Antipsychotic drugs: _____________________________________________________________
Most common are: 1. _________________ (ex.,chlorpromazine - Thorazine)2. ________________ (ex.,haloperidol - Haldol)
- they are also known as “__________________”One mechanism of action: ___________________________________________________
used to treat psychoticconditions such as schizophrenia, paranoia, etc.
Phenothiazines
Butyrophenones
major tranquilizersblock dopamine
receptors, particularly the D2 subtype.
The devastating effects of schizophrenia
. . . and the hope given by antipsychotics
III. Antidepressant drugs: __________________________________________Most common are:1. ______________________________ (MAOI)2. ________________ (ex., imipramine - Tofranil)3. __________________________________ (SSRIs
ex., fluoxetine - Prozac)Mechanisms of action:- MAOIs block the breakdown of ____________(especially _______________________________)- Tricyclics and SSRIs block ___________________________ (especially _____________________)
used to treat depressive illnesses
Monoamine oxidase inhibitorsTricyclicsSerotonin-specific reuptake inhibitors
monoaminesserotonin [5-HT] and noradrenaline
the reuptake of monoamines noradrenaline and 5-HT
IV. Opiates (analgesics): ________________________________________- high potential for addiction (see next section)Most common are:1. ______________________ (morphine, codeine)2. _____________________ (heroin)3. _____________________: made in the body =endorphins (enkephalins, dynorphin)
Mechanism of action: all work by binding _______________ in the nervous system (___, ____, and_______ subtypes of opiate receptors)
V. Stimulants: __________________________________________________
Several classes of stimulants:1. _____________________ (ex., cocaine, “crack”,amphetamine)
2. __________________ (ex., pentylenetetrazol)3. ________________________ (ex., caffeine)4. ____________________ (ex., lysergic aciddiethylamide [LSD], mescaline, marijuana, psilocybin [from some mushroom])Varied mechanisms of action.
clinically employed in the treatment of pain
Opium poppy derivativesDerivatives of morphineEndogenous morphine
opiate receptors mu delta kappa
in general, increase activity of the nervous system
Behavioral stimulants
Convulsant stimulantsGeneral stimulantsPsychedelic drugs
WHAT IS DRUG ADDICTION (DEPENDENCE)
Substance Abuse:_____________________________________________________________________________
Drug Dependence (Addiction): ___________________________________________________________________________________
Important concepts:1. Drug tolerance: _______________________________________________________________________________________________________________________________________- _________________: reduced sensitivity to a drug that results from the increased ability of the body to metabolize the drug- _______________: a change that takes place innerve cells in which the activity of neuronsadjust to the excitatory or inhibitory effects of adrug (ex., receptor downregulation)- _______________: behavior change acquired through associative learning
decreased susceptibility to a drug that develops as a result of repeated exposure to a drug; compensatory mechanisms opposite to initial drug effectmetabolic tolerance
cellular tolerance
learned tolerance
pattern of drug use in which chronic and excessive intake takes a central place in ones life.
advanced state of abuse in which physical and psychological dependence have developed.
Example of tolerance to some drug actions
2. Sensitization: ____________________________________________________- for example, the behavioral activity of animals in responseto repeated injections of amphetamine increases over time.
increased behavioral response to the same dose of a drug
3. Physical dependence: ___________________ _______________________________________________________________
state in which discontinuation of drug taking will induce withdrawal syndrome
Psychological dependence is the most importantfactor in addictive behavior - produces“compulsive” drug taking behavior
Withdrawal syndrome: ______________________________________________________________________________________________
- physical dependence was originally thought tobe responsible for addictive behavior
- however, if true, treating addicts until physicalwithdrawal is over should treat addiction; itdoes not
illness induced by the elimination or absence from the body of a drug on which a person is physically dependent
Learning, through associative conditioning,produce ______________________________- associative learning= ______________________:______________________________________________________________;
- if high drug dose taken somewhere else, can belethal
Siegel injected morphine in rats for several daysin a very distinct environment- on the last day he compared the lethal effects ofa large dose of morphine in animals placed inthe same distinct context where they had received prior morphine injections or in acontext where they had not received morphine
- many rats receiving morphine in the newcontext did not survive the higher dose.
- produces ___________________________:_____________________________________________________________________
- if eliminate cues associated with drug, canreduce addiction (ex., Vietman vets.)
psychological dependence (Siegel)conditioned drug tolerance
only places and cues associated with drug taking will produce tolerance
conditioned withdrawal effects - places and cues associated with drug can also produce withdrawal symptoms
THEORY of ADDICTION
Believed to develop in stages:1. Seeking the sensation of pleasure from drug
taking;2. Pleasure is linked to mental representations
(cues) associated with drug taking;3. Cues associated with drug taking cues become
incentives, through sensitization process.
Substance abuse progresses such that ______________ of drugs are required to produce apleasurable effect, and are eventually incapableof producing pleasurable feelings.So why do people keep taking these substances?Theory of ___________________: ________________________________________________________________________________________________________________________________________
- greatly increases the “wanting” for a drug even if the “liking” is reduced.
increasingdoses
incentive-sensitization cues associated with drug taking become “attached” with motivational properties, which become “sensitized” (increase) with repeated drug taking.
Investigating craving . . .
The brain and rewarding processes
Reinforcement: ____________________________________________________________________ __________________________________________________________- important factor in producing addiction
Addictive drugs have reinforcing effects:- they activate reinforcement mechanisms- reinforcement strengthens behavior justpreceding it
Discovery of Reinforcing Brain Stimulation:(Olds & Milner, 1954) Classic study
Electrodes implantedin medial forebrainbundle (MFB)
- rats found to pressa lever thousandsof times an hourto receiveelectrical stimulation
reinforcement is the process by which there is an increase in the likelihood of occurrence of most recent behavior preceding the reinforcement
Neural System of Reinforcement_________________involved in reinforcement- system starts in a collection of neurons called __________________________), which contains _________ as a
neurotransmitter- most important projections of VTA axons to _________________ (dopamine receptor antagonists in this
region block Medial Forebrain Bundle (MFB) self-stim.)- blockade of dopamine receptors in nucleus accumbenscan also block drug taking behavior in animal models of
addiction.
Mesolimbic systemventral
tegmental area -VTA dopamine
nucleusaccumbens
Treatments of Commonly Abused Substances
General adverse consequences of abused drugs:- ________________________________________- ________________________________________- ________________________________________- ________________________________________- ________________________________________- _________________________________________________________
Expensive habit (associated with crime);IV injections – health risks (HIV, hepatitis);Source can be doubtful and plain dangerous;Crosses placental barrier, making fetus depend;Overdose can produce death;Some drugs can lead to neurological disorders and brain damage.
Neural mechanisms of drug action: act at specific, and often, multiple, synaptic receptors.Common withdrawal symptoms: from 2-3 hours until 6-7 days after last ingestion/dose;
- some withdrawal symptoms: increased fidgeting, sweat, sleep, shiver, nausea, vomiting, diarrhea, cramps, tremors, muscle spasms (legs – going “cold turkey” and “kicking” the habit!)
Specific Treatments:- in some cases, drug specific treatments areavailable (ex. methadone maintenance for opiates)- in general NO GOOD TREATMENTS for anyaddictive drugs!
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