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Muscarinic M2‐receptors enhance polyphosphoinositol release in rat gastric mucosal cells
Author(s) -
Pfeiffer Andreas,
Paumgartner Gustav,
Herz Albert
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80842-0
Subject(s) - pirenzepine , carbachol , muscarinic acetylcholine receptor , inositol phosphate , inositol , atropine , second messenger system , endocrinology , chemistry , muscarinic acetylcholine receptor m1 , receptor , medicine , muscarinic acetylcholine receptor m3 , biology , biochemistry
Muscarinic receptor types and their effects on the inositol phosphate second messenger system were studied in enzymatically dispersed rat gastric mucosal cells. Radioreeeptor binding studies indicated the presence of a single class of binding sites (4860 ± 875) and affinities of 0.42 ± 0.12 nM, 176 ± 32 nM and 13 μM for N ‐methylscopolamine, pirenzepine and carbachol, respectively. In cells prelabelled with myo ‐[ 3 H]inositol carbachol induced a dose‐dependent increase in inositol‐1‐phosphate in the presence of lithium with an ED 50 of 10 μM which was antagonized by atropine and pirenzepine (IC 50 9 and 700 nM, respectively). Carbachol stimulated amino[ 14 C]pyrine uptake, used as a measure of acid secretion, with an ED 50 of 10 μM. The good correlation between these responses suggests a role for inositol phosphates in the muscarinic M2‐receptor mediated acid secretion.