Heart Rate and Extracellular Sodium and Potassium Modulation of Gap Junction Mediated Conduction in Guinea Pigs.

ABSTRACT:

Background

Recent studies suggested that cardiac conduction in murine hearts with narrow perinexi and 50% reduced connexin43 (Cx43) expression is more sensitive to relatively physiological changes of extracellular potassium ([K(+)]o) and sodium ([Na(+)]o).

Purpose

Determine whether similar [K(+)]o and [Na(+)]o changes alter conduction velocity (CV) sensitivity to pharmacologic gap junction (GJ) uncoupling in guinea pigs.

Methods

[K(+)]o and [Na(+)]o were varied in Langendorff perfused guinea pig ventricles (Solution A: [K(+)]o = 4.56 and [Na(+)]o = 153.3 mM. Solution B: [K(+)]o = 6.95 and [Na(+)]o = 145.5 mM). Gap junctions were inhibited with carbenoxolone (CBX) (15 and 30 μM). Epicardial CV was quantified by optical mapping. Perinexal width was measured with transmi

SUBMITTER: Entz M 

PROVIDER: S-EPMC4735342 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature