Veterinary Neuropharmacology

MUSCARINIC RECEPTOR SUBTYPES

	M1	M2	M3
Location and function subserved	Autonomic ganglia – depolarization (Late EPSP) Gastric glands – histamine induced release of acid secretion CNS – no precise activity is documented till date	SA node – hyperpolarization Decreased rate of impulse generation AV node – decreased conduction velocity Atrium – decreased contractility Ventricles – decreased contractility	Visceral smooth muscle – contraction Exocrine glands – increases secretion
Nature	G -protein	G -protein	G -protein
Agonist	Oxotremorine	Methacholine	Bethanechol
Antagonist	Pirenzepine	Methoctramine	-