PSYC62H3 Lecture Notes - Lecture 6: Chronic Obstructive Pulmonary Disease, Nicotinic Acetylcholine Receptor, Acetylcholine Receptor
21 Feb 2017
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Cont"d from lecture 5: mild compared to major stimulants pharmacologically. Tar adheres to tissues in mouth, nose, throat, lungs, and skin. Freebase forms of nicotine best absorbs through mucous membranes in the mouth. Peak absorption is 7 min. (cigarettes) to 25 min. (smokeless tobacco. In liver, cyp-2a6 enzymes metabolize 80 90% of nicotine producing the. Half-life for nicotine is approx 2 hours products) active metabolite cotinine: chronic smokers have a 30% faster elimination rate of nicotine than nonsmokers. Effect on the nervous system (midterm): nicotine is an agonist for cholinergic nicotinic receptors, receptors quickly desensitize: Channels close and cannot be opened even when agonist is bound: nicotine is also a functional antagonist. Receptors remain in an inactivated state longer than an activated state. Now some of these receptors are nonfunctional: pns: increases sympathetic nervous system activity. Heart rate, respiration rate, constricting blood supply: cns: increases dopamine release in nucleus accumbens. Also influences acetylcholine, glutamate, gaba, norepinephrine, serotonin, and vasopressin.
