PHAR 300 Lecture Notes - Lecture 10: Nicotinic Acetylcholine Receptor, Nucleus Accumbens, Mesolimbic Pathway
10 Jan 2019
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Document Summary
Highest prevalence rates of smoking are in people suffering from psychiatric illness and addiction. Epidemiology of smoking: 88% in schizophrenia, 75% depression, 80% alcoholism, 29% general population. Usually takes many attempts to give up smoking. Many types of nicotinic receptors in vta: activates neuron in vta and nucleus accumbens (dopamine and serotonin, respectively, a4b2. Notably on gaba neurons which are supposed to inhibit the dopamine neuron. Mechanism: receptors desensitize rapidly, making the cell less susceptible to being activated by cholinergic input, lowering activation of the inhibitory cell: a7. Notably glutamate neurons, which excite the dopamine neuron. Don"t desensitize and release glutamate for longer. Recording of action potentials reflect this: firing rate increases with nicotine. There are many benefits of quitting smoking. Risk of lung cancer decreases when you quit. The number of receptors in the brain of a smoker becomes abnormal as alpha-7 receptors are (technically) downregulated and a4b2 receptors are technically upregulated (my hypothesis)
