Inhibitory action of ptilomycalin A-mimic on catecholamine secretion evoked by acetylcholine from cultured bovine adrenal chromaffin cells

• Published in: Japanese Journal of Pharmacology Vol. 82; no. suppl.1; p. 125
• Main Authors: Azuma, Mami, Suzaki, Yuki, Fujimoto, Mariko, Ichimaru, Katsuhiko, Umeda, Takabumi, Kujime, Toshihide, Houchi, Hitoshi, Tamaki, Toshiaki, Minakuchi, Kazuo
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Pharmacological Society 2000
• ISSN: 0021-5198
• DOI: 10.1016/S0021-5198(19)47963-8

Ptilomycalin A, an ATPase modulater, was isolated from the marine sponge Plilocaulis spiculfer. Ptilomycalin Amimic (PA-M) is a novel product which is synthesized on the model of ptilomycalin A. The effect of PA-M, the pharmacological function is unknown, on catecholamine secretion from bovine adrenal chromaffin cells was examined. PA-M inhibited catecholamine secretion stimulated by 10^-4 M acetylcholine. This inhibitory action of PA-M (10^-8 M-10^-5 M) was dose-dependent manner. At the presense of 3X10^-7 PA-M, the catecholamine secretion stimulated by increasing acetylcholine up to 10^-3 M was not observed the maximal level without PA-M. 10^-5 M PA-M suppressed both the increase in intracellular free Ca^2+ level and the influx of ^^45 Ca^2+ induced by 10^-4 M acetyicholine. The PA-M-induced suppression was not observed in the action evoked by extracellular 56mM K^+ . It is indicated that PA-M suppressed the Ca^2+ influx related with the acetylcholine receptor and inhibited the following catecholamine secretion. These results indicate that PA-M may modulate stimulus-secretion coupling in adrenal medulla.