Effects of Stimulants

Question 1

what are the general effects of stimulants? what is the one exception?

Answer 1

• they are virtually doing the same thing: activating the sympathetic nervous system producing physiological symptoms associated with the “fight or flight” reaction (ie. increased HR, increased body temp, increased BP, sweating, vasoconstriction, bronchodilation etc) - not sought after effects
• an exception is cocaine: it has local anaesthetic effects and produces profound vasoconstriction and for this, it is still considered a medical drug (useful in surgeries requiring localizing anaesthesia and control bleeding)

Question 2

what are the effects of alcohol and cocaine combined

Answer 2

• breakdown of cocaine when alcohol is also present produces a metabolite called “cocaethylene” which has potent effects like increased blood pressure and heart rate and it increases the elimination half-life of cocaine
• partly responsible for the 25 fold increase in the risk of immediate death from simultaneous consumption of alcohol and cocaine
• has eu[horic effects that produce more pleasure than cocaine alone

Question 3

what is the half-life of cocaine?

Answer 3

• 40mins and a noticeable decline in as little as 20mins

Question 4

what is the half-life of amphetamine?

Answer 4

• about 8hrs and a decline in effect that unlikely to be noticed for about 4hrs

Question 5

how did Freud view cocaine?

Answer 5

• he believed that people would take the drug to alleviate depression which would result in self-medication

Question 6

what are classified as psychomotor stimulants? what is motor behaviour typically measured by - but what does it lose on the process?

Answer 6

• cocaine, amphetamines and methamphetamine bc they increase motor behaviour
• typically measured by means of photobeam boxes and computer technologies - it loses the qualitative description of psychomotor drugs
• behavioural effects are dose-related but it is possible to produce with a sufficiently larger single dose

Question 7

behavioural scale from Robbins:

Answer 7

• Hyperactive: increase in motor behaviour characterized by running and rapid, jerky changes in position
• Slow-patterned: the pace of movement will have slowed but not there’s a discernible pattern
• Fast-patterned: the pace of movement increases (sudden start and stops)
• in-place restricted: relevant to stimulant psychosis in humans
• Dyskinetic, convulsive: behaviours activating effects of stimulants are due to the ability of these drugs to increase dopaminergic activity by causing the release and blocking

Question 8

Stereotypies

Answer 8

• repetitive, ritualistic and nonfunctional behaviours

Question 9

stimulants and breakpoints

Answer 9

• stimulants support the highest breakpoints of all drugs and cocaine supports the highest breakpoint among stimulants

Question 10

what is the typical pattern of stimulant administration and the self-paradigm?

Answer 10

• animal works over the course of a few days to administer larger doses at small intervals until they are convulsing (and cant press the lever) but as soon as they recover they return to this pattern of rapid administration of high doses

Question 11

fetal effects and stimulants? - cocaine specific

Answer 11

• the study suggested that if infants were exposed to cocaine they had a signigicant depression of interactive behaviours and poor organizational responses to environmental stimuli (but more evidence was needed)
• “crack baby” was the name infants were called to describe offsprings whose mothers were using crack while pregnant
• suggested to suffer from substantial and irreversible damage
  Cocaine specific:
• low birth weight and length (dissapears over time)
• cognitive impairments abd difficulty in language learning
• tendancy to show externalizing behaviours

Question 12

neurochemical effects of stimulants

Answer 12

• clear evidence that most psychoactive effects of stimulants involved increased dopaminergic activation
• rewarding effects result from increased dopamine release and blockade of reuptake of dopamine in the VTA-NAcc neural pathway

Question 13

which stimulants cause the leakage of dopamine in the absence of action potentials or actually cause the release of more dopamine per action potential?

Answer 13

• amphetamines and methamphetamines

Question 14

which stimulant primarily blocks the reuptake released dopamine?

Answer 14

• cocaine

Question 15

when would the rewarding effects of cocaine, amphetamine and methylphenidate decrease?

Answer 15

• reduce if dopamingeric receptor blockers

Question 16

effects of stimulants on the dopamine reward system?

Answer 16

• “stimulant blues”/”cocaine blues” happens when someone binges on stimulants during a short interval of time the rewarding effects of the stimulant will diminish to the point of being absent
• even if a person stops taking the stimulant they will feel often depressed and unable to experience pleasure from normally pleasurable life events - ANHEDONIA
• with a long enough drug-free period newly synthesized dopamine becomes available for release and the stimulant blues have disappeared

Question 17

anhedonia

Answer 17

• due to the depletion of dopamine as a result from the stimulant causing dopamine to continously be leaked from the presynaptic terminal