Format

Send to

Choose Destination
Eur J Pharmacol. 1990 Apr 10;179(1-2):225-9.

The allosteric binding profile of himbacine: a comparison with other cardioselective muscarinic antagonists.

Author information

1
Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore 21201.

Abstract

The possibility of an allosteric interaction by himbacine, a cardioselective antagonist, with rat cardiac muscarinic receptors was studied. Himbacine allosterically decelerated the dissociation of bound [3H]N-methylscopolamine [( 3H]NMS) in a concentration-dependent manner with an IC50 value of 103.7 microM. When compared to the IC50 values of other cardioselective antagonists, the rank order of potencies was: methoctramine greater than gallamine greater than himbacine greater than AF-DX 116. In contrast, the potencies of these compounds to displace [3H]NMS binding were: himbacine greater than methoctramine greater than AF-DX 116 greater than gallamine. The allosteric potencies were found not to be correlated with binding potencies (correlation coefficient = -0.15). A striking common feature of the cardioselective antagonists is their ability to bind to an allosteric site on cardiac muscarinic receptors.

PMID:
2364985
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center