Sodium Fluoride Mimics the Effect of Prostaglandin E2on Catecholamine Release from Bovine Adrenal Chromaffin Cells
作者:
Seiji Ito,
Manabu Negishi,
Noriko Mochizuki‐Oda,
Hiromitsu Yokohama,
Osamu Hayaishi,
期刊:
Journal of Neurochemistry
(WILEY Available online 1991)
卷期:
Volume 56,
issue 1
页码: 44-51
ISSN:0022-3042
年代: 1991
DOI:10.1111/j.1471-4159.1991.tb02560.x
出版商: Blackwell Publishing Ltd
关键词: Prostaglandin E2;Sodium fluoride;G protein;Phosphoinositide metabolism;Catecholamine release;Bovine adrenal chromaffin cells
数据来源: WILEY
摘要:
Abstract:We have reported recently that prostaglandin E2(PGE2) stimulated phosphoinositide metabolism in bovine adrenal chromaffin cells and that PGE2and ouabain, an inhibitor of Na+,K+‐ATPase, synergistically induced a gradual secretion of catecholamines from the cells. Here we examined the involvement of a GTP‐binding protein(s) in PGE receptor‐induced responses by using NaF. In the presence of Ca2+in the medium, NaF stimulated the formation of all three inositol phosphates, i.e., inositol monophosphate, bisphosphate, and trisphosphate, linearly over 30 min in a dose‐dependent manner (15–30 mM). This effect on phosphoinositide metabolism was accompanied by an increase in cytosolic free Ca2+. NaF also induced catecholamine release from chromaffin cells, and the dependency of stimulation of the release on NaF concentration was well correlated with those of NaF‐enhanced inositol phosphate formation and increase in cytosolic free Ca2+. Although the effect of NaF on PGE2‐induced catecholamine release in the presence of ouabain was additive at concentrations below 20 mM, there was no additive effect at 25 mMNaF. Furthermore, the time course of catecholamine release stimulated by 20 mMNaF in the presence of ouabain was quite similar to that by 1 μMPGE2, and both stimulations were markedly inhibited by amiloride, with half‐maximal inhibition at 10 μM.Pretreatment of the cells with pertussis toxin did not prevent, but rather enhanced, PGE2‐induced catecholamine release over the range of concentrations examined. These results demonstrate that NaF mimics the effect of PGE2on catecholamine release from chromaffin cells and suggest that PGE2‐evoked catecholamine release may be mediated by the stimulation of phosphoinositide metabolism through a putative GTP‐binding protein insensi
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