Macrovascular endothelial cells express voltage-gated K+ channels but appear to lack Ca2+ and Na+ channels. The goal of this study was to begin characterizing ion channels in cardiac microvascular endothelial cells (CMECs). CMECs were isolated from rat ventricular muscle and studied between days 1-5 in culture. Differential uptake of flourescently-labeled acetylated LDL indicated that the primary culture contained > 90 % CMECs. Membrane currents were measured using the whole-cell arrangement of the patch clamp technique. Cells were dialyzed with internal Cs+ to block the outward K+ currents. Voltage steps positive to -30 mV resulted in the activation of inward Na+currents (INa). In 10 cells analyzed, the peak INa was 2.5 pA/pF and the current inactivated with a V1/2 of -45 mV. INa was eliminated by replacement of external sodium with N-methylglucamine and was blocked by tetrodotoxin (Kd = 3 nM). Voltage-gated Na+ channels may promote electrical conduction between capillaries and arterioles following membrane (Figure Presented) depolarization.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology