Protein kinase C activators reduce the inositol trisphosphate‐Induced outward current and the CA2+‐activated outward current in identified neurons of aplysia

Publisher Website
Google Scholar
Abstract
Effects of intracellularly injected activators of protein kinase C on the InsP3‐induced K+ current and the Ca2+‐activated K+ current recorded from identified neurons (R9—R12) of Aplysia kurodai were investigated with conventional voltage‐clamp and pressureinjection techniques. Intracellular injection of InsP3 into identified neurons produced a 4‐aminopiridine (4‐AP)‐resistant, tetraethylammonium (TEA)‐sensitive, and quinidine‐sensitive K+ current similar to the Ca2+ activated K+ current elicited by direct injection of Ca2+ ions into the same neurons. The diacylglycerol analogue 1,2‐oleoylacetylglycerol (OAG) at an intracellular concentration of 65 nM produced irreversible decreases in both the InsP3 ‐induced K+ current and the Ca2+ ‐activated K+ current. The phorbol 12,13‐dibutyrate (PDBu) at an intracellular concentration of 150 nM also decreased irreversibly both the InsP3 ‐induced K+ current and the Ca2+ ‐activated K+ current. These results suggest that protein kinase C activators reduce both the InsP3 ‐induced K+ current and the Ca2+ ‐activated K+ current recorded from certain identified neurons of Aplysia and that protein kinase C reduces the ability of Ca2+ to open K+ channels rather than affecting the ability of InsP3 to release Ca2+ from intracellular stores.