ganglionic stimulants and blockers Flashcards
ONE ganglionic stimulant important medically
nicotine -releases DA in the brain can reach brain in 6 seconds -oily liquid alkaloid -rapidly absorbed from smoke in lung or mouth
nicotine receptors
nAChR expressed on DA neurons which are plentiful in VTA of midbrain
stimulation of DA
in nucleus accumbens and prefrontal cortex
what increases nicotine addiction
MAOI
-tobacco contains naturally occurring MAOI’s
CNS actions of nicotine
- increases alertness
- calming effect
- enhances motor sensory abilities
- relaxes skeletal muscle by inhibiting spinal reflexes
- analgesia
- prevents parkinsonism
nicotine used to break smoking habit
satisfy craving without smoking
- chew nicotine gum (chew gum slowly)
- nicotine spray
- nicotine transdermal
medical precautions of smoking
Related to sympathetic
- hypertension
- paroxysmal atrial tachycardia
- peripheral vascular disease
Related to parasympathetic
- IBS
- peptic ulcer
- colitis
- colic in an infant (milk/plasma ratio=2.9)
other actions of nicotine
-skeletal muscle effect only at high doses (not enough in cigarettes)
Symptoms of mild intoxication with gum:
-increased salivation
-nausea due to sensory nerves in stomach
-increase respiration due to carotid sinus stimulation
what does fetal/neonatal nicotine exposure causes
type 2 diabetes
- 15-20% pregnant women smoke
- nicotine destroys insulin secreting cells by mito apoptosis
non-nicotine for smoking cessation
Varenicline (nicotine analog)
- partial agonist at nicotine receptors in mesolimbic dopaminergic system
- decreases smoking satisfaction as antagonist
- counteracts craving as agonist
- clinical studies show increase success with counseling
- nausea usually mild
what are some other treatments for smoking cessation
bupropion
antidepressants (blocks NET, DAT)
may block some nicotines effect
dry mouth, insomnia
serious nicotine toxicity
- Not common in humans
- can be lethal at dose of 60mg
no specific antidote for nicotine
Artificial respiration till effect wears off
-half-life: 2 hours (oxidized in liver)
what were the first orally effective anti-hypertensives
ganglionic blockers
- limited use now
- sometimes used to orthopedic surgery to decrease BP and blood loss
classes of ganglionic blockers
first stimulate then block (nicotine)
block without first stimulating (Mecamylamine)
