Nicotine Addiction Flashcards
what is addiction?
a brain disorder characterised by compulsive engagement in rewarding stimuli, despite adverse consequences
what are the outputs of nicotine metabolism?
70-80% = cytochrome P450 ~10% = other metabolites ~10% = excreted in urine
what are the two stages of drug addiction?
impulsive and compulsive stage
what is the mesolimbic pathway?
a dopamine pathway
ventral tegmental area projects the the nucleus accumbens and the striatum
How do many addictive drugs work in relation to the mesolimbic pathway?
the drugs enhance dopamine release in the VTA to Nacc pathway
what is the first stage of nicotine addiction mechanisms?
nicotinic receptors in reward system mediate reinforcing events
what is the second stage of nicotine addiction mechanism?
repeated exposure to nicotine induces tolerance.
acute tolerance is mediated by desensitisation of nAChRs.
chronic tolerance can lead to upregulation of nAChR expression in the PFC of the brain
what is the third stage of nicotine addiction mechanisms?
two-stage neuroadaption in the VTA, Nacc and amygdala.
this occurs via opponent process model.
what is the fourth stage of nicotine addiction mechanisms?
PFC-Nacc glutaminergic pathway is altered and response inhibition and impulse control is compromised
what is the fifth stage of nicotine addiction mechanisms?
PFC-dorsal striatum projection strengthened and smoking becomes automatic, habitual and compulsive
what is the sixth stage of nicotine addiction mechanisms?
reduced gray matter and neural activity in the prefrontal cortex
what are three pharmacological interventions for nicotine addiction?
nicotine replacement.
Buprofin: an antidepressent, DA uptake inhibitor
varenciline: partial agonist for high affinity nAChRs
