Definition
An anticholinergic agent is a substance that blocks
the neurotransmitter acetylcholine in the central and
the peripheral nervous system
Anticholinergics are administered to reduce the
effects mediated by acetylcholine on acetylcholine
receptors in neurons through competitive inhibition
, ANTICHOLINERGIC DRUGS
(Muscarinic Receptor Antagonist,
Para-sympatholytics, Cholinolytics
Atropine-like Drugs)
Atropine, the prototype drug of this class,
is a highly selective blocking agent for pre
and post-muscarinic receptors,
but some of its synthetic derivatives have
significant nicotinic blocking property as well.
, Atropine blocks ACh
M-effects of ACh
A 1 min B C D
200
Blood pressure [mm Hg]
150
100
50 M- M- N-
effect effect effect
ACh ACh Atropine ACh ACh
2 mcg i.v. 50 mcg 2 mg i.v. 50 mcg 5 mg
, Tropane alkaloids
• Atropine
• Scopolamine (Hyoscine)
• Solanine
Atropa belladonna L.
(deadly night shade)