BOT 1200 Lecture Notes - Lecture 19: Nicotiana Tabacum, Jean Nicot, Nicotinic Acetylcholine Receptor
30 Mar 2016
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Document Summary
Most psychoactive chemicals contain nitrogen and are alkaloids. Anexception is the active compound in marijuana, deltatrans- tetrahydrocannabinol (thc) Psychoactive drugs act on cells of the central and peripheral nervous systems by altering the interaction between neurons and neurotransmitters. Drugs either mimic (agonist) or block (antagonist) the actions of the neurotransitters. Originally, narcotic referred to a substance that induces central nervous system depression (eg. opiates) Today, the term narcotic is used to describe psychoactive compounds that are addictive. Stimulants promote mental alertness, reduce fatigue and suppress hunger (caffeine, nicotine, cocaine) A member of the solanaceace (nightshade) family. Members of this family have tubular- shaped flowers. Nicotine mimics acetylcholine action in the brain, and binds to the nicotinic receptor on the surface of dopaminergic neurons. Dopamine levels are increased in the nucleus accumbens part of the brain. Tobacco consumption increases the number of nicotinic receptors in the brain. Highest concentration (0. 5 to 10mg per g of leaves) is in the uppermost leaves.
