PT  - JOURNAL ARTICLE
AU  - A L Garcia-Villalon
AU  - D N Krause
AU  - F J Ehlert
AU  - S P Duckles
TI  - Heterogeneity of muscarinic receptor subtypes in cerebral blood vessels.
DP  - 1991 Jul 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 304--310
VI  - 258
IP  - 1
4099  - http://jpet.aspetjournals.org/content/258/1/304.short
4100  - http://jpet.aspetjournals.org/content/258/1/304.full
SO  - J Pharmacol Exp Ther1991 Jul 01; 258
AB  - The identity and distribution of muscarinic cholinergic receptor subtypes and associated signal transduction mechanisms was characterized for the cerebral circulation using correlated functional and biochemical investigations. Subtypes were distinguished by the relative affinities of a panel of muscarinic antagonists, pirenzepine, AF-DX 116 [11-2-[[2-[diethylaminomethyl]- 1-piperidinyl]acetyl]-5,11-dihydro-6H- pyrido[2,3-b][1,4]benzodiazepine-6-one], hexahydrosiladifenidol, methoctramine, 4-diphenylacetoxy-N-methylpiperidine methobromide, dicyclomine, para-fluoro-hexahydrosiladifenidol and atropine. Muscarinic receptors characterized by inhibition of [3H]quinuclidinylbenzilate binding in membranes of bovine pial arteries were of the M2 subtype. In contrast pharmacological analysis of [3H]-quinuclidinylbenzilate binding in bovine intracerebral microvessels suggests the presence of an M4 subtype. Receptors mediating endothelium-dependent vasodilation in rabbit pial arteries were of the M3 subtype, whereas muscarinic receptors stimulating endothelium-independent phosphoinositide hydrolysis in bovine pial arteries were of the M1 subtype. These findings suggest that characteristics of muscarinic receptors in cerebral blood vessels vary depending on the type of vessel, cellular location and function mediated.