Voltage-Activated Ionic Currents in Myoepithelial Cells Isolated from the Sea Anemone Calliactis Tricolor

Abstract

Myoepithelial cells were isolated from the apical ends of mesenteries of the sea anemone Calliactis tricolor and examined using the whole-cell configuration of the patch-clamp technique. The isolation procedure produced cell fragments that were contractile and produced action potentials when depolarized. These action potentials are formed by a complex array of ionic currents consisting of at least one, and possibly two, inward calcium currents and four outward potassium currents. The ionic selectivity of the calcium currents was Ca2+>Sr2+>Ba2+. Outward currents consisted of a calcium-dependent outward current and three voltage-activated currents, including a 4-aminopyridine-sensitive current, a transient outward current and a steady-state current.