MolPharm xPharm- The Comprehensive Pharmacology Reference

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Regunathan, S.
Right arrow Articles by Reis, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Regunathan, S.
Right arrow Articles by Reis, D. J.

Clonidine-displacing substance from bovine brain binds to imidazoline receptors and releases catecholamines in adrenal chromaffin cells

S Regunathan, MP Meeley and DJ Reis

Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021.

Identification of nonadrenergic binding sites for clonidine and related imidazolines in brain and peripheral tissues and partial purification of an endogenous ligand for these sites have led to the postulation of a novel transmitter/receptor system. The receptors seem to be present in adrenal medulla and to regulate chromaffin cell function. The present study was undertaken to test the ability of the putative endogenous ligand clonidine-displacing substance (CDS) to displace [3H]idazoxan binding to adrenal chromaffin cell membranes and to release catecholamines from cultured chromaffin cells. CDS potently displaces [3H]idazoxan binding to chromaffin cell membranes, with an IC50 of 5 units. The displacement of [3H]idazoxan binding by CDS was not modified by guanosine 5'-(beta, gamma-imido)triphosphate, suggesting that the imidazoline binding sites may not be GTP-binding protein-coupled receptors. CDS produced a large release of catecholamines from chromaffin cells, and the release was partially blocked by cobalt, a calcium channel blocker. The calcium-dependent release reached a plateau above 5 units of CDS, with a maximal response at 15 min. It is concluded that endogenous CDS, prepared from brain, regulates the secretion of catecholamines from adrenal chromaffin cells, probably by activating imidazole receptors.

Volume 40, Issue 6, pp. 884-888, 12/01/1991
Copyright © 1991 by American Society for Pharmacology and Experimental Therapeutics




This article has been cited by other articles:


Home page
 Ann. N. Y. Acad. Sci.Home page
D. J. REIS and S. REGUNATHAN
Agmatine: An Endogenous Ligand at Imidazoline Receptors Is a Novel Neurotransmitter
Ann. N.Y. Acad. Sci., June 21, 1999; 881(1): 65 - 80.
[Abstract] [Full Text] [PDF]

Home page
 Ann. N. Y. Acad. Sci.Home page
P. R. KING, A. L GUNDLACH, and W. J. LOUIS
Identification of Imidazoline-Receptor Binding Sites in Cortex and Medulla of the Bovine Adrenal Gland: Colocalization with MAO-A and MAO-B
Ann. N.Y. Acad. Sci., June 21, 1999; 881(1): 161 - 170.
[Abstract] [Full Text] [PDF]

Home page
 ScienceHome page
D. J. Reis, G. Li, S. Regunathan, C. J. Barrow, and R. Cooper
Response
Science, October 21, 1994; 266(5184): 463 - 464.
[PDF]

Home page
 ScienceHome page
G Li, S Regunathan, C. Barrow, J Eshraghi, R Cooper, and D. Reis
Agmatine: an endogenous clonidine-displacing substance in the brain
Science, February 18, 1994; 263(5149): 966 - 969.
[Abstract] [PDF]


Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
All ASPET Journals Molecular Pharmacology Pharmacological Reviews
Molecular Interventions Drug Metabolism and Disposition

Copyright © 1991 by the American Society for Pharmacology and Experimental Therapeutics