cholinergic N S

Acetyl choline
Clinically limited in use because:
- destroyed by acetylcholinesterase
- is not selective
Butyrylcholinesterases
Endogenous Ach effect???

Receptors:
-Nicotinic R( N) : it activated by nicotine
small dose of nicotine stim ganglia release of Ach or noradrenalin
large dose inhibition to autonomic ganglia (euphoria)
Its 2 type:
* neuronal type (Nn) : in CNS, adrenal medulla & ANS ganglia (st ganglia adre why?????
ST Nn neurotransmiter in ganglia release of adrenaline from adrenal medulla.
*neuromuscular type (Nm) : found in neuromuscular junction cause contraction of sk.m.
Muscarinic R : it activated byMuscarin poisonous mushroom used experimentally only.


M1 found in gastric parietal cell
M2 found on cardiac cell & sm
M3 on bladder , exocrine gland & sm
M4-M5 on CNS
Nicotinic R act by ion channel linked R
Muscarinic R act by activation G-pr but :
mechanism of action

M 1 , 3 M2
activate phospholipase C inhibit adenylyl cyclase
IP3 & DAG K conductance
Ca release heart rate & force
cellular effect.