Chapter 8 Flashcards
What are the two types of nicotine plant
Tabacum and Rustica
what family of plants does tobacco belong to
the nightshade family
which tobacco plant is the primary source of our nicotine and tobacco and why
primarily from the tabacum plant becaue rustica is harder to cultivate, and additionally contains other psychoactive substances including a hallucinogen
what is the process of preparing tobacco for smoking
dried or cured after harvest and then fermented (but its actually more oxidsation than real fermentation)
how do vapes work
liquid containing nicotine and propylene glycol + glycerin and water is aerosalised by the heating element so that vapours can be released into the lungs
how did the tobacco industry avoid FDA control for so long
claiming that tobacco products were only sold for smoking pleasure, not effects of nicotine
why was nicotine never self administered in its pure form like cocaine (coca) or morphine (opium poppy) until recently
nicotine is highly toxic so its dosing has to be controlled very precisely
what are the three main ways of tobacco use
- inhalation into lungs
- insufflation (dry snuff, although that is getting to be more and more uncommon)
- orally (chewing, moist snuff, etc)
what happens when nicotine smoke or vapours is inhaled
the particles dissolve in the mucous membranes in the lungs. this is the primary way that nicotine makes it into the blood stream (about 90%)
is nicotine an acid or a base
it is a weak base
what type of receptor does nicotine bind to
nicotinic cholinergic receptors which are ionotropic acetylcholine receptors
what happens when nicotine binds to a receptor
it opens a sodium channel, depolarising the cell membrane (note: some subtypes do affect potassium instead)
what does it mean for tobacco to be flue-cured
when the smoke dissolves in saliva, the saliva becomess more acidic, making the mouth a more hostile environment for nicotine ions and prevents them from being absorbedw
what does it mean for tobacco to be air cured
when the smoke is dissolved in saliva, it makes the saliva Less acidic, allowing nicotine to be absorbed through the mouth
what was the first nicotine replacement therapy product developed
nicotine chewing gome
nicotine is metabolised into two inactive metabolites. these are:
- cotinine (about 75% of nic metabolites)
- nicotine-1’-N-oxide
what is the estimated half life of nicotine
between 90 and 150 minutes
true or false: females metabolise nicotine faster. why or why not
true. the cytochrome P450 2A6 (CYP2A6) enzyme that is primarily responsible for breakdown is induced by estrogen
how does eating effect nicotine metabolism
metabolism is quickened by eating as eating causes an increase of bloodflow to the liver, where nicotine is primarily metabolised
what determines excretion level of nicotine
acidity of the urine. thats why someone who is stressed smokes more. their urine is more acidic so their levels drop faster since theres less reabsorption through the nephron
nicotinic receptors are pentameric. what does this mean
similar to GABA receptors, they are made up of five units that are organised in a ring around a central pore
what is nicotines effect on the peripheral nervous system
nicotinic receptors in the PNS act at junctions of striated muscles and control voluntary muscle action
what is nicotines effect on the central nervous system
nicotinic receptor in the CNS are involved in cogntive functions such as learning and memory
what is a basal state
when the ion channel is closed and the receptor has a high affinity for ligands
what is an active state
ion channel is open and there is low affinity for ligands
what is a desensitised state
ion channel is closed and the receptor is unresponsive to ligands
if repeatedly activated, the receptor will enter which state
the desensitised state
which receptot state is thought to contribute to acute nicotine tolerance
the desensitised stateq
why are high doses of nicotine lethal
it paralyses the muscles used in breathing
in rats, nicotine will fully substitute for which other drug?
cocaine
why do smokers appear to age faster than non-smokers
constriction of blood vessels in the skin contributing to wrinkle formation
true or false: cigarrettes can be used as laxative
technically yea, particularily in someone with low tolerance because nicotine stimulates activity in the bowel
