Opposite regulation of KCNQ5 and TRPC6 channels contributes to vasopressin-stimulated calcium spiking responses in A7r5 vascular smooth muscle cells.

ABSTRACT: Physiologically relevant concentrations of [Arg(8)]-vasopressin (AVP) induce repetitive action potential firing and Ca(2+) spiking responses in the A7r5 rat aortic smooth muscle cell line. These responses may be triggered by suppression of KCNQ potassium currents and/or activation of non-selective cation currents. Here we examine the relative contributions of KCNQ5 channels and TRPC6 non-selective cation channels to AVP-stimulated Ca(2+) spiking using patch clamp electrophysiology and fura-2 fluorescence measurements in A7r5 cells. KCNQ5 or TRPC6 channel expression levels were suppressed by short hairpin RNA constructs. KCNQ5 knockdown resulted in more positive resting membrane potentials and induced spontaneous action potential firing and Ca(2+) spiking. However physiological concentratio

SUBMITTER: Mani BK 

PROVIDER: S-EPMC2744104 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature