Class 4 Cholinergics and blockers - Ch 20 21 CHOLINERGICS...

Ch. 20, 21
CHOLINERGICS
And
CHOLINERGIC BLOCKERS

Parasympathetic Nervous System

cholinergic receptors [two types]

based on location & their action

Nicotinic {N} “nicotinic” because stimulated by

alkaloid nicotine

&

Muscarinic {M} because stimulated by alkaloid
“muscarine”

B r a i n S p i n a l C o r d
C e n t r a l
S o m a t i c
[ s k e l e t a l m u s c l e ]
P a r a s y m p a t h e t i c
[ A C h ]
1 2
a l p h a
1 2
b e t a
S y p a t h e t i c
[ N E & E P I ]
A u t o n o m i c
P e r i p h e r a l
N e r v o u s   S y s t e m

Mode of Action of Cholinergics

Direct-Acting

bind to cholinergic receptors & activate

Indirect-Acting

work by making more acetylcholine available at
receptor by inhibiting enzyme
“cholinesterase”

CHOLINERGICS
Direct Acting Indirect-Acting
acetylcholine
bethanechol
carbachol
pilocarpine
ambenonium
demecarium
physostigmine
echothiophate
isoflurophate
pyridostigmine
edrophonium
neostigmine
methacholine

Direct Effect of Cholinergics

effects seen when stimulate the parasympathetic
nervous system

“rest” & “digest” system
REMEMBER SLUDGE (or Pee, Poop, Puke)

salivation

lacrimation

urinary incontinence

diarrhea

gastrointestinal cramps

emesis

Drug Effects-Cholinergics
stimulate intestine & bladder
✓
increased gastric secretions & GI motility
✓
increased urinary frequency
stimulate pupil
✓
constriction {miosis}
✓
decreased intraocular pressure
increased salivation & sweating

Drug effect of Cholinergics

cardiovascular effects
✓
decreased heart rate & vasodilation

respiratory effects
✓
constrict & narrow airways

at recommended doses the cholinergics
primarily effect muscarinic but at high doses
nicotinic