Cocaine & Amphetamines Flashcards
Describe the 3 routes of administration.
The most rapid and highest peak is produced by intravenous administration.
Smoking the freebase is similarly rapid but less pronounced peak.
Snorting has the most delayed effects
Describe the relationship between cocaine use and DA levels and mood.
Initially increased synaptic concentrations of DA associated with euphoria are followed by relatively reduced synaptic concentrations of DA associated with craving and dysphoria.
How are cocaine effects mediated by its actions on the sympathetic nervous system?
SNS activation speeds things up increasing alertness and heart rate as well as blood flow - accounts for the high.
HOWEVER, side effects of vasoconstriction and hypertension increase the risk of stroke intracranial haemorrhage
How does cocaine work?
DA travels down the axon in the vesicles which merge with the pre-synaptic membrane to release DA.
Cocaine blocks the DA transporter meaning levels of DA within the synaptic cleft are increased.
It also inhibits other transporters to increase synaptic levels of NA and 5-HT.
Is cocaine reinforcing?
Amphetamines are reinforcing - COCAINE IS NOT
Describe Rocha et al., 1998 findings on reinforcing properties of cocaine in wild-type or knockout mice
The knockout mice lacked the DA transporter and the wild-type control mice steadily pressed the lever more than the knock out mice.
this confirms the role of the DA transporter for the reinforcing effects of cocaine
How do cocaine’s actions depend on the administration schedule.
Chronic long-term treatment with cocaine ca produce tolerance.
Chronic pre-treatment with continuous infusion produces tolerance - the effect of the cocaine challenge was reduced in the group that had been treated with continuous infusion over 11 days.
Describe the mechanisms of amphetamine action.
DA travels down the axon in vesicles which merge with presynaptic membrane to release DA.
Amphetamine is an indirect DA agonist. It is take up by DA transporter to enter the neurone terminal and stimulates the release of DA. The DA transporter is confused and release more DA.
