Stimulants (for exam 3)

PSYC 733

what factors contribute to the high associated with stimulants?

• increased DA release

• blocked reuptake of DA, NE, and 5-HT

benzoylecogine

• the active metabolite in cocaine

• contributes to the effects of cocaine

cocoethylene

• produced when cocaine and alcohol are used together

• similar action to cocaine with longer half-life

mild vs severe effects of stimulants

severe effects are basically more intense versions of moderate effects

EX)inflated self-esteem—> delusions of grandiosity; sleep disturbance—> insomnia

how do basal levels of DA impact individual responses to the euphoric effects of cocaine?

• low DA in cleft = less high

• high DA in cleft = greater high

what are the long-term changes in the NAcc that decrease the euphoric effects of drugs?

• decreased intracellular DA levels and release

• decreased baseline rate of DA uptake

• decreased ability of cocaine to block DAT and inhibit reuptake

• decreased sensitivity of terminal D2 DA autoreceptors

how does chronic cocaine use alter the dorsal striatum?

decreased functioning of DA system

neurochemical effects of cocaine vs methamphetamine vs amphetamine

• cocaine is a MA reuptake inhibitor ; amphetamine and methamphetamine are indirect CA agonists

• cocaine increases the amount of DA, NE, and 5-HT ; amphetamine and methamphetamine only increase the amount of DA

what are the behavioral and neurochemical effects of stimulant injections into the NAcc?

• shell: reward/reinforcement

• core: psychostimulant hyperlocomotion

confirmed with self-admin and 6-OHDA lesion studies

which of the dopaminergic pathways in the brain is most vulnerable to the neurotoxic effects of methamphetamine?

nigrostriatal pathway

according to Amy Arnsten, how do psychostimulants act in the PFC to alter attention?

• PFC functioning is an inverted U-shaped function of DA and NE activity

  • too little NE/DA = poor attention

  • too much NE/DA = hyperactivity and distractibility.

• middle ground: optimal alpha-2A and D1 receptor activation

alpha-2A receptors

• NE

• enhances strength of relevant sensory input (increase signal)

D1 receptors

• DA

• weakens irrelevant sensory input