Conventionally, anticholinergic drugs are those which block actions of ACh on autonomic effectors and in the CNS exerted through muscarinic receptors. Though nicotinic antagonists also block certain actions of ACh, they are generally referred to as ‘ganglion blockers’ and ‘neuromuscular blockers’.
ANTICHOLINERGIC DRUGS
(Muscarinic Receptor Antagonists, Atropinic,
Parasympatholytic)
Conventionally,
anticholinergic drugs are those which block actions of ACh on autonomic effectors
and in the CNS exerted through muscarinic receptors. Though nicotinic
antagonists also block certain actions of ACh, they are generally referred to
as ‘ganglion blockers’ and ‘neuromuscular blockers’.
Atropine,
the prototype drug of this class, is highly selective for muscarinic receptors,
but some of its synthetic substitutes do possess significant nicotinic blocking
property in addition. The selective action of atropine can easily be demonstrated
on a piece of guinea pig ileum where ACh induced contractions are blocked
without affecting those evoked by histamine, 5HT
or
other spasmogens. The selectivity is, however, lost at very high doses. All
anticholinergics are competitive antagonists.
Related Topics
TH 2019 - 2024 pharmacy180.com; Developed by Therithal info.