Inositol trisphosphate accumulation by high K+ stimulation in cultured adrenal chromaffin cells

[摘要]

Stimulation with high K⁺ (KCl, 56 mM) of myo-[³H]inositol-prelabelled cells increased Ca²⁺ uptake and [³H]inositol trisphosphate (IP₃) accumulation in a concentration-dependent manner. Nifedipine, a Ca²⁺ channel antagonist, inhibited high K⁺-induced [³H]IP₃ accumulation and ⁴⁵Ca²⁺ uptake with a similar potency. Furthermore, ionomycin (1 μM), a Ca²⁺ ionophore, also induced ⁴⁵Ca²⁺ uptake and [³H]IP₃ accumulation. These results indicate the existence of the Ca²⁺ uptake-triggered mechanism of IP₃ formation in cultured adrenal chromaffin cells.

[学科分类] 生物化学/生物物理

[关键词] Inositol trisphosphate accumulation;Ca2+ uptake;High K+ stimulation;(Adrenal chromaffin cell)