|
|
||||||||
AJP - Cell Physiology, Vol 271, Issue 6 C1963-C1972, Copyright © 1996 by American Physiological Society
ARTICLES |
D. J. Culp, W. Luo, L. A. Richardson, G. E. Watson and L. R. Latchney
Department of Dental Research, University of Rochester, New York 14642, USA.
We investigated the role of M1 and M3 receptors in regulating exocrine secretion from acini isolated from rat sublingual glands. In secretion experiments, we derived affinity values (KB) from Schild regression analysis for the antagonists pirenzepine (61.0 nM) and 4-diphenylacetoxy-N-methylpiperidine (4-DAMP; 1.06 nM). The KB for 4-DAMP is similar to its affinity value [equilibrium dissociation constant from competition studies (Ki); 1.81 nM] determined from radioligand competition experiments. In contrast, the KB for pirenzepine is between its high-affinity (17.6 nM) and low-affinity (404 nM) Ki values. In separate secretion experiments, we found that the M1 receptor antagonist, M1-toxin, induces a rightward shift in the concentration-response curve to muscarinic agonist and inhibits maximal secretion by 40%. The inhibitory effect of M1-toxin appears specific for M1 receptor blockade, since the toxin abolishes acinar high-affinity pirenzepine-binding sites and does not inhibit secretion induced by nonmuscarinic agents. Additional pharmacological studies indicate muscarinic receptors do not function through putative neural elements within isolated acini. Our combined results are consistent with both M1 and M3 receptors directly regulating mucous acinar exocrine secretion and indicate M3 receptors alone are insufficient to induce a maximal muscarinic response.
This article has been cited by other articles:
![]() |
G. B. Proctor Muscarinic receptors and salivary secretion J Appl Physiol, April 1, 2006; 100(4): 1103 - 1104. [Full Text] [PDF] |
||||
![]() |
G. Tobin, A. T. Ryberg, S. Gentle, and A. V. Edwards Distribution and function of muscarinic receptor subtypes in the ovine submandibular gland J Appl Physiol, April 1, 2006; 100(4): 1215 - 1223. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Luo, L. R. Latchney, and D. J. Culp G protein coupling to M1 and M3 muscarinic receptors in sublingual glands Am J Physiol Cell Physiol, April 1, 2001; 280(4): C884 - C896. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |