Characterization of an apamin-sensitive small-conductance Ca(2+)-activated K(+) channel in porcine coronary artery endothelium: relevance to EDHF.

ABSTRACT: 1. The apamin-sensitive small-conductance Ca(2+)-activated K(+) channel (SK(Ca)) was characterized in porcine coronary arteries. 2. In intact arteries, 100 nM substance P and 600 microM 1-ethyl-2-benzimidazolinone (1-EBIO) produced endothelial cell hyperpolarizations (27.8 +/- 0.8 mV and 24.1 +/- 1.0 mV, respectively). Charybdotoxin (100 nM) abolished the 1-EBIO response but substance P continued to induce a hyperpolarization (25.8 +/- 0.3 mV). 3. In freshly-isolated endothelial cells, outside-out patch recordings revealed a unitary K(+) conductance of 6.8 +/- 0.04 pS. The open-probability was increased by Ca(2+) and reduced by apamin (100 nM). Substance P activated an outward current under whole-cell perforated-patch conditions and a component of this current (38%) was inhibited by apamin

SUBMITTER: Burnham MP 

PROVIDER: S-EPMC1573217 | biostudies-literature | 2002 Mar

REPOSITORIES: biostudies-literature