Muscarinic Receptors in Chromaffin Cell Cultures Mediate Enhanced Phospholipid Labeling but Not Catecholamine Secretion |
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Authors: | Stephen K. Fisher,Ronald W. Holz,&dagger ,Bernard W. Agranoff |
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Affiliation: | Neuroscience Laboratory, Mental Health Research Institute, and Department of Biological Chemistry, University of Michigan;Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, U.S.A. |
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Abstract: | Abstract: The addition of either carbachol or muscarinic agonists to cultured bovine adrenal chromaffin cells results in a selective stimulation of phosphatidate (PhA) and phosphatidylinositol (PhI) labeling from 32Pi and [3H]glycerol that can be inhibited by the inclusion of atropine, but not d -tubocurarine. In contrast, increased catecholamine secretion is observed on the addition of carbachol or nicotinic agonists and is inhibited by d -tubocurarine but not by atropine. Added calcium is essential for catecholamine secretion but not for stimulated phospholipid labeling. Chelation of endogenous Ca2+ with EGTA does, however, inhibit the stimulated phospholipid labeling. These results suggest that stimulated phospholipid labeling in the bovine chromaffin cell and catecholamine secretion are separate and distinct processes. |
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Keywords: | Cholinergic agonist Muscarinic receptor Bovine adrenal chromaffin cell Phosphatidate Phosphatidylinositol |
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