Stimulants 3 Nicotine Flashcards

1
Q

Along with caffeine and alcohol, one of the most widely
used psychoactives in the world and routinely rated by addicts as the toughest substance to stop using

A

Nicotine

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2
Q

Nicotine is who’s neurotoxic defense against
insects, works like other ACh-agonist toxins, paralyzing insects that eat the leaves

A

Tobacco plant

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3
Q

Nicotine is a what agonist

A

ACh

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4
Q

admin of nicotine is customarily

A

inhalation or mucous membrane

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5
Q

nicotine can also be absorbed through what (ie transdermal patches)

A

skin

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6
Q

leads to good absorption from intestines
(nicotine is basic)

A

oral administration

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7
Q

this admin is not useful because nicotine undergoes extensive (90%) first pass metabolism

A

PO

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8
Q

passively slips through this with ease

A

BBB

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9
Q

elimination is

A

fairly quick (T1/2 ~ 2± hours)

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10
Q

the most important metabolizing
enzyme, converting nicotine mostly to cotinine

A

Cytochrome P450 CYP2A6

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11
Q

stress accelerates

A

nicotine metabolism

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12
Q

tobacco farmers who handle the leaves (wet) without gloves can have nicotine seep into the skin/clothing, causing them to get sick

A

green tobacco sickness

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13
Q

What does this mean for smokers’ reports that smoking helps them feel less stressed?

A

nicotine gets metabolized quicker, sends them into a state of nicotine withdrawal, smoking makes the withdrawal go away

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14
Q

main route for metabolite elimination

A

urine

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15
Q

Nicotine acts mainly as a direct agonist at what, causing Na+ influx = EPSP

A

nicotinic Ach receptors

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16
Q

The key effect is activation of these excitatory nicotinic receptors located on

A

VTA dopamine neurons

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17
Q

activation of these excitatory nicotinic receptors located on VTA dopamine neurons leads to

A

increased activity in mesolimbic “reward” circuitry (but not nearly to the extent that cocaine or amphetamines can increase it)

18
Q

activation of these excitatory nicotinic receptors located on VTA dopamine neurons ends up also activating

A

endogenous opioid systems

19
Q

Curiously, at very high doses, nicotine begins to have what effects on ACh activity (tolerance???)

A

antagonist

20
Q

among the estimated 4700 chemicals in tobacco smoke,
something appears to work as an MAOI (i.e., slowing the
breakdown of DA, NE, 5-HT), not nicotine itself, but most likely

A

beta carbolines

21
Q

mesocortical nicotinic receptor activation can lead to

A

more dopamine activity and attention in frontal lobe

22
Q

Like caffeine, increased alertness, attention/concentration, working memory (overall sharpening of mental functioning), reduced hunger

A

psychoactive effects of nicotine

23
Q

Many persons have inadvertently discovered it as “self-
medication” for

24
Q

Smoking rates are extremely high among

A

schizophrenic persons

25
However, the data are fewer on the cognitive benefits among
non-patient smokers
26
Equivocal data exist on whether smoking increases
testosterone levels
27
develops quickly (within hours), mostly though desensitization of NAChRs, this tends to keep smokers puffing away throughout the day, lost once the smoker stops smoking for the day, the next day the building starts anew
tolerance
28
this develops – metabolic? (GTS is more common & severe among nonsmokers)
longer term tolerance
29
But overall, tolerance to nicotine is far less than tolerance to
other addictive drugs
30
craving, grouchiness, ↓ mental sharpness, hunger, frustration, restlessness, anhedonia, beginning within hours of deprivation, weight gain is a common longer-term consequence
withdrawal side effects
31
The role of nicotine-related cues (conditioned stimuli)
cannot be overstated
32
inability to feel pleasure
anhedonia
33
needed to cause nicotine toxicity via PO admin
enormous amounts
34
could be as low as 60mg or as high as >1g
LD50
35
this way of entry is more problematic (e.g., green tobacco sickness, insecticide exposure; e-cig liquid)
transdermal
36
follows a biphasic pattern
toxicity
37
cholinergic stimulation symptoms predominate: nausea, vomiting, diarrhea, muscle fasciculations, tachycardia and hypertension occur initially
first phase of toxicity
38
symptoms appear to relate to cholinergic inhibition, likely a product of extreme NAChR desensitization, bradycardia, cardiac arrhythmia, hypotension, coma, and respiratory, muscle failure, which typically leads to death if not treated
second phase of toxicity
39
Gums, patches, lozenges, inhalers, etc. provide low dose nicotine so that users can slowly taper their use (wean themselves) without experiencing unbearable withdrawal symptoms.
Nicotine replacement therapies
40
Nicotinic ACh receptor antagonist (Presumably counteracts the effects of nicotine), Also a DA & NE reuptake blocker (Presumably allows mesolimbic DA activity to stay high, thus minimizing withdrawal symptoms)
Zyban / Wellbutrin (bupropion)
41
“Partial agonist” at nicotinic ACh receptors – competes with ACh and nicotine, binds to receptors and can activate, but is less likely to activate them than ACh or nicotine is, limits psychoactive effect of nicotine
Chantix (varenicline)