Ganglionic Stimulants and Blockers Flashcards
What is the only medically important ganglionic stimulant?
Nicotine
What effect does nicotine have on the brain?
Nicotine receptors (nAChR) are expressed on DA neurons which are plentiful in VTA of midbrain
- –stimulate releases D in nucleus accumbens and prefrontal cortex
- –creates pleasurable experiences
What other CNS actions does nicotine have?
- Increases alertness
- Calming effect
- Enhances motor and sensory abilities
- Relaxes skeletal mm by inhibiting spinal reflexes
- Analgesia
- Prevents parkinsonism
How can nicotine be used in a positive way?
To break smoking habits
- -satisfy craving w/o smoking
- –chew nicotine gum
- –nicotine spray (oral or nasal)
- –nicotine transdermal
(only about 25% effective)
How does taking 4 mg nicotine gum compare with smoking tobacco?
Cigarette gives much more nicotine, almost peaking at 30 ng/ml where as the gum barely reaches 10 ng/ml
Electronic cigarettes
Tx has become disease
Pure nicotine causes medical problems
What medical precautions of smoking due to nicotine in tobacco or in electric cigarettes should be taken?
Nicotine makes bronchospasms worse
Sympathetic effects
- -increases BP, so worsen HTN
- -paroxysmal atrial tachy
- -peripheral vascular disease
Parasympathetic effects
- -IBS
- -Peptic ulcer
- -Colitis
- -Colic in an infant (nursing mother)
Does nicotine effect skeletal mm?
At high doses
What are the symptoms of mild intoxication with nicotine gum?
Increased salivation
Nausea due to sensory nerves in stomach
Inc respiration due to carotid sinus stim
What effect does nicotine exposure have on fetuses and neonates?
Causes type 2 diabetes
15-20% of pregnant women smoke
Nicotine destroys insulin secreting cells by mitochondrial apoptosis
What are some non-nicotine tx for smoking cessation?
Varenicline
Bupropion
Varenicline
- -what is it?
- -how does it work?
- -side effect?
Nicotine analogue
- -Partial agnoist at nicotinic receptors in mesolimbic dopaminergic system
- -decreases smoking satisfaction (acting as antagonist)
- -counteracts craving (acting as agonist)
- -Nausea usually mild
- -may cause depression and suicidal thoughts
Bupropion
- -what is it?
- -how is it speculated to work?
- -side effect?
Antidepressants (blocks NET, DAT)
May block some of nicotine’s effects
Dry mouth, insomnia
Serious nicotine toxicity
Not common in humans
Lethal Dose ~ 60 mg in adult humans
- -cigarette contains ~ 8 mg
- -smoker gets ~ 2 mg/cig
Children may consume cigarettes but nicotine in leaf not absorbed well
Is there an antidote for nicotine?
No specific antidote
Artificial respiration till effect wears off
T1/2 =~2 hr
—oxidized in the liver
