Psychomotor Stimulants Flashcards
What are naturally occurring amphetamine-like compounds?
cathinone
ephedrine/pseudoephedrine
What is the function of cathinone?
potent stimulant, increases HR, excitement, euphoria, anorectic
What is the function of ephedrine?
constricts the nasal blood vessels reducing congestion
What are some medical uses for amphetamines?
reducing congestion alertness anorectic antidepressant attention deficits
What are the major effects of amphetamines on humans?
autonomic function analeptic anorectic decreased fatigue alertness euphoria withdrawal psychosis
What are the major effects of amphetamines on non-human animals?
autonomic functions
psychomotor stimulant
reinforcement
fragmentation of natural behaviours
What are the possible forms of cocaine?
raw leaves paste hydrochloride free base crack
How do the different forms of cocaine affect its function?
changes the method of administration
paste/free base/crack; smokable
hydrochloride; injected
Describe the pharmacokinetics of cocaine
rapid metabolism and elimination
half life; 0.5-1.5 hours
What are the differences between the action of cocaine and amphetamine?
duration of action
cardiovascular effects
What are the effects of repeated psychostimulant administration?
tolerance; escalation of dose for same effect
sensitisation; decreased dose for same effect
What can cause psychostimulant tolerance?
closely spaced drug exposure
continuous drug infusion
binge usage
What can happens in psychostimulant sensitisation?
psychoses
punding
animals; increased locomotor activity/stereotypy
What can influence psychostimulant sensitisation?
stress
sex; increased in females
rate of infusion
administration environment
What are catecholamines?
neurotransmitters mediating reward
Name the catecholamines
dopamine
epinephrine
norepinephrine
Name an indolamine and its function
serotonin; mood regulation
How are catecholamines synthesised?
tyrosine
Where are DA cell bodies?
VTA/nigra
Where are NE cell bodies?
locus coeruleus
Where is NE released from?
sympathetic nervous system and adrenal glands
Where is serotonin released from?
raphe nuclei
What are the types of monoamine?
catecholamine
indolamine
What is the rate-limiting step in catecholamine synthesis?
tyrosine-hydroxylate
What is dopamine synthesised from?
L-dopa
What is l-dopa synthesised from?
l-tyrosine
What is NE synthesised from?
dopamine
What is epinephrine synthesised from?
NE
What are monoamines packed into vesicles by?
VMAT2
What are monoamines degraded by?
monoamine oxidase
Where is dopamine expression particularly high?
striatum neurons
~ half express D1
~ half express D2
what is the difference in action of D1 and D2?
d1 stimulates
d2 reduces
What types are the d1 class?
d1, d5
what types are in the d2 class?
d2, d3, d4
What is the primary site of action of amphetamines and cocaine?
monoamine transporters
What action does cocaine have on monoamines and where?
blocks DAT
enhances size and duration of monoamine release events
2-4 fold increase in stratal DA
What action do amphetamines have on monoamines?
stimulate DA release by inhibiting storage
reverse DAT
What is the core mechanism or cocaine addiction?
DAT blockade
Dopamine blockade in which brain area disrupts cocaine self-administration?
NAcc
Which neural system promotes psychomotor and rewarding effects?
increased DA transmission at DA terminals in SN and VTA
Which pathways involve drug seeking?
excitatory input to VTA
