Am J Physiol Cell Physiol Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 265: C666-C673, 1993;
0363-6143/93 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
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 Yang, C. M.
Right arrow Articles by Wu, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yang, C. M.
Right arrow Articles by Wu, D.

AJP - Cell Physiology, Vol 265, Issue 3 C666-C673, Copyright © 1993 by American Physiological Society

ARTICLES

Pharmacological characterization of muscarinic receptors in neonatal rat cardiomyocytes

C. M. Yang, F. F. Chen, T. C. Sung, H. F. Hsu and D. Wu
Department of Pharmacology, Chang Gung Medical College, Tao-Yuan, Taiwan, Republic of China.

[N-methyl-3H]scopolamine methylchloride ([3H]NMS) was used to characterize the muscarinic receptors (mAChRs) in the intact cardiomyocytes. The specific binding of [3H]NMS was proportional to cell concentration, saturable with respect to [3H]NMS concentration, and time dependent. Scatchard analysis of binding isotherms showed that [3H]NMS bound to the freshly isolated and cultured cardiomyocytes with dissociation constants of 275 +/- 64 and 207 +/- 20 pM as well as maximum receptor densities of 0.13 +/- 0.09 and 5.36 +/- 0.20 fmol/10(5) cells, respectively. Heterogeneity of mAChRs was demonstrated by competitive binding experiments against [3H]NMS with M2 and M3 antagonists. These receptors (80%) exhibited high affinities for 11-([2-[(diethylamino)methyl]-1-piperidinyl]-acetyl)-5,11-dihydro- 6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX-116) and methoctramine similar to those of M2 subtype. The low-affinity M2 antagonist binding constants were close to those reported for M3 receptors and possessed high affinity for 4-diphenylacetoxyl-N-methylpiperidine (4-DAMP) and hexahydrosiladifenidol. On the basis of biochemical studies, AF-DX-116 blocked adenosine 3',5'-cyclic monophosphate (cAMP) inhibition with high affinity (pKB 7.4), while it antagonized inositol phosphate formation with low affinity (pKB 6.5). 4-DAMP possessed high affinity in blocking inositol phosphate formation (pKB 9.0) and low affinity for antagonism of cAMP inhibition (pKB 7.7). Although no other muscarinic receptor mRNA has been detected in these cells, these data suggest the presence of a second population of mAChRs, which may not be identical to the classical cardiac "M2" receptors.


This article has been cited by other articles:


Home page
 Mol. Pharmacol.Home page
A. Krejci and S. Tucek
Quantitation of mRNAs for M1 to M5 Subtypes of Muscarinic Receptors in Rat Heart and Brain Cortex
Mol. Pharmacol., June 1, 2002; 61(6): 1267 - 1272.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
U. Mende, A. Kagen, M. Meister, and E. J. Neer
Signal Transduction in Atria and Ventricles of Mice With Transient Cardiac Expression of Activated G Protein {alpha}q
Circ. Res., November 26, 1999; 85(11): 1085 - 1091.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
H. M. Colecraft, J. P. Egamino, V. K. Sharma, and S.-S. Sheu
Signaling Mechanisms Underlying Muscarinic Receptor-mediated Increase in Contraction Rate in Cultured Heart Cells
J. Biol. Chem., November 27, 1998; 273(48): 32158 - 32166.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
R. A. Kelly, J.-L. Balligand, and T. W. Smith
Nitric Oxide and Cardiac Function
Circ. Res., September 1, 1996; 79(3): 363 - 380.
[Full Text]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online