Referenced in: none

Automatically associated channels: Kir2.3 , Slo1

Title: Target size analysis of skeletal muscle Ca2+ channels. Positive allosteric heterotropic regulation by d-cis-diltiazem is associated with apparent channel oligomer dissociation.

Authors: A Goll, D R Ferry, H Glossmann

Journal, date & volume: FEBS Lett., 1983 Jun 27 , 157, 63-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/6305718

Abstract
[3H]PN 200-110, a potent chiral benzoxadiazol 1,4-dihydropyridine Ca2+ antagonist was used to label guinea pig skeletal muscle Ca2+ channels. [3H]PN 200-110 binds with a Kd of approximately 1 nM to a homogeneous population of non-interacting binding sites; d-cis-diltiazem, but not l-cis-diltiazem increases the Bmax of [3H]PN 200-110 by 25% and slows the dissociation rate 3-fold at 37 degrees C. Target size analysis of the [3H]PN 200-110-labelled Ca2+ channels with 10 MeV electrons gave an Mr of 136 000 which was reduced to 75 000 by d-cis-diltiazem treatment of membranes. It is concluded that positive heterotropic allosteric regulation by d-cis-diltiazem is accompanied by channel oligomer dissociation.