nervous system pns c ns *afferent n *brain *efferent n
TRANSCRIPT
Ca
Hemicholinum ---
botulinum toxin --- spider toxin++ clostiridium
Presynaptic R
Uses:
Clinically limited in use because:
- destroyed by acetylcholinesterase
- is not selective
Endogenous Ach effect???
Cholinergic 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
*neuromuscular type (Nm) : found in neuromuscular junction cause contraction of sk.m.
Muscarinic R : M1-M5
it activated by Muscarin poisonous mushroom used experimentally only.
M found on ganglia in PNS
M1 found in gastric parietal cell
M2 found on cardiac cell & sm
M3 on bladder, exocrine gland, sm, endothelium
M4-M5 on CNS
MOA:
nicotinic R act by ion channel linked R.
Muscarinic R act by activation G-pr but :
M 1 , 3 M2
activate phospholipase C inhibit adenylyl cyclase
IP3: i/c ca st or inh E, K conductance
heart rate & force secretion, contraction
DAG: activate pr kinase C phosphorylation pr cellular eff
NOTE: M1 agonist in Rx of Alzheimer D
M3 blocker RX COPD.
or Agonists): cholinomimeticsCholinergic drug (
1- direct acting cholinomimetic
They act where Ach is physiologically released &
amplifiers of endogenous Ach.
*** Bethanechol
- Synthetic esters of choline so not destroyed
by cholinesterase enzyme.
- Strong muscarinic activity & no nicotinic
effect
- Act on sm of bladder & git causing increase intestinal motility & stimulate detrusor muscle of bladder & relaxed the sphincter
used in:
- atonic bladder due postoperative and non obstructive urine retention
- in neurogenic atony and megacolon
SE:
All effect of cholinergic stimulation
sweating, salivation , flushing , hypotension abd pain , diarrhea & bronchospasm .
Contraindication:
-in asthmatic patients
-in bladder weakness and mechanical
obstruction ( it cause rupture of
bladder).
-in hypotension
-in peptic ulcer ( it increase git gland
secretion)
Carbachol
- Synthetic esters of choline so
-not destroyed by cholinesterase enzyme.
- have muscarinic & nicotinic effect
-has st effect on ganglia adre epinep
- mainly affect CVS & GIT
iopdecrease because glaucomaused in -and cause miosis.
***Pilocarpine
- naturally occurring alkaloid
- not destroyed by cholinesterase because
tertiary amine
-potent muscarinic agonist
-used in emergency increase in (iop)
( it opening the trabecular meshwork
around the schlemm canal .
-used as mouth spray in xerostomia due
to radiation of head & neck.(why)
SE:
-blurred vision and night blindness
-increase salivation and sweating in
toxicity with pilocarpine