Korean J Physiol Pharmacol.  1997 Apr;1(2):169-183.

Two types of voltage-dependent outward potassium currents in smooth muscle cells of rabbit basilar artery

• Kang TM
• So I
• Uhm DY
• Kim KW

Abstract

We have investigated the two types of voltage-dependent outward potassium (K) currents, i.e. delayed rectifier K current (I-K(V)) and 'A-like' transient outward K current (I-to) with patch-clamp technique in single smooth muscle cells (SMCs) isolated from rabbit basilar artery, and investigated the characteristics of them. The time-courses of activation were well fitted by exponential function raised to second power (n-2) in I-K(v) and fourth power (n-4) in I-to. The activation, inactivation and recovery time courses of I-to were much faster than that of I-K(V). The steady-state activation and inactivation of I-K(V) was at the more hyperpolarized range than that of I-to contrary to the reports in other vascular SMCs. Tetraethylammonium chloride (TEA; 10 mM) markedly inhibited I-K(V) but little affected 1-to. 4-Aminopyridine (4-AP) had similar inhibitory potency on both currents. While a low concentration of Cd-2+ (0.5 mM) shifted the current-voltage relationship of I-to to the positive direction without change of maximum conductance, Cd-2+ did not cause any appreciable change for I-K(V).

Keyword

Basilar artery; Delaryed rectifier K crrent; Transient outward K current

MeSH Terms

4-Aminopyridine
Basilar Artery*
Muscle, Smooth*
Myocytes, Smooth Muscle*
Patch-Clamp Techniques
Potassium*
Tetraethylammonium
4-Aminopyridine
Potassium
Tetraethylammonium