Muscarinic receptor subtypes in bovine adrenal medulla |
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Authors: | José S Aguilar Juan J Ballesta Juan A Reig Mercedes Palmero Salvador Viniegra Manuel Criado |
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Institution: | (1) Departmento de Neuroquímica, Universidad de Alicante, Ap. 374, 03080 Alicante, Spain;(2) Present address: Dept. of Pharmacology, University of Illinois at Chicago, 835 S. Wolcott Ave., 60612 Chicago, IL;(3) Instituto de Neurociencias, Universidad de Alicante, Ap. 374, 03080 Alicante, Spain |
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Abstract: | Catecholamine secretion in the bovine adrenal medulla is evoked largely by nicotinic receptor activation. However, bovine adrenal medulla also contain muscarinic receptors that mediate several cell responses. To understand the physiological role of muscarinic receptors in the bovine adrenal medulla it is important to identify the pharmacological subtypes present in this tissue. For this, we analyzed the abilities of differnt selective muscarinic antagonists in displacing the binding of the non-selective antagonist 3H] quinuclidinyl benzylate to an enriched plasma membrane fraction prepared from bovine adrenal medulla. All the selective antagonists bind at least two bindings sites with different affinities. The binding profile of the sites with high proportion is similar to the M2 subtype and those present in low proportion have a M1 profile. However, some variation in the proportion of the sites for the different ligands suggest the presence of the third pharmacological subtype (M3). We conclude that the sites in high proportion (60–80%) correspond to M2 muscarinic subtypes, and the rest is constitute by M1 plus M3 subtypes. The presence of multiplicity of subtypes in the adrenal medulla membranes suggests a diversity of functions of muscarinic receptors in the adrenal gland.Abbreviations 3H]QNB
3H]quinuclidinyl benzylate
- HHSiD
hexahydro-siladifenidol-hydrochloride
- AF-DX 116
11-2-(diethylamino)methyl]]-1-piperidinyl]-5,11-dihydro-6H-pyrido2,3,-b]1,4]benzodiazepin-6-one
- 4-DAMP
4-diphenylacetoxy-N-methyl piperidine methobromide |
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Keywords: | Muscarinic receptor Receptor subtypes bovine adrenal medulla |
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