Calcium modulation of 5-HT3 receptor binding and function.

ABSTRACT: Calcium modulates the 5-HT3 receptor response by reducing peak current amplitude and increasing rates of activation, deactivation and desensitisation, but the binding site(s) and mechanism(s) of this modulation are unknown. Here we study residues that may be involved in calcium binding in two partially overlapping regions of the extracellular domain (E213-E215-E218 and D204-E218-V219). The modulatory effects of calcium were assessed by radioligand binding and whole-cell patch-clamp. Comparisons of [3H]granisetron binding showed an increase in Kd in 10mM calcium that was abolished by the substitutions E213Q, E215Q, D204N and V219L. E218Q mutant receptors displayed no specific binding or function, and immunofluorescence showed that they did not reach the cell surface. E213Q increased inheren

SUBMITTER: Thompson AJ 

PROVIDER: S-EPMC2649430 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature