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Bradykinin Stimulates Phosphoinositide Hydrolysis and Mobilization of Arachidonic Acid in Dorsal Root Ganglion Neurons
Author(s) -
Gammon Charles M.,
Allen Ann C.,
Morell Pierre
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb07299.x
Subject(s) - arachidonic acid , chemistry , inositol , diacylglycerol lipase , diglyceride , inositol phosphate , medicine , endocrinology , calcium , biochemistry , phosphatidylinositol , diacylglycerol kinase , biology , fatty acid , receptor , protein kinase c , signal transduction , organic chemistry , enzyme
Abstract: Cultures of fetal rat dorsal root ganglion neurons (7 days in culture) were prelabeled with myo ‐[ 3 H]inositol or [ 3 H]arachidonic acid for 24 h and stimulated with 10 μ M bradykinin for time intervals of 5–300 s. The incubation was terminated by addition of 5% perchloric acid to extract inositol phosphates or organic solvent to extract lipids. Inositol phosphates were resolved by anion‐exchange HPLC; lipids were resolved by TLC. Bradykinin stimulation resulted in a 10‐fold increased accumulation of inositol 1,4,5‐trisphosphate (IP 3 ) and inositol bisphosphate (IP 2 ) (fivefold) by 5 s. The increase in IP 3 was transient (half maximal by 1 min), whereas stimulated IP 2 levels were sustained for several minutes. Even longer term increases were observed in inositol monophosphate. Stimulation also resulted in a threefold increase in arachidonic acid which was preceded by transient increases in diacylglycerol (twofold) and arachidonoyl‐monoacylgly‐cerol (threefold). The temporal lag in the accumulation of arachidonic acid with respect to diglyceride and monoglyc‐eride suggested the involvement of di‐ and monoglyceride lipases in arachidonic acid mobilization. A role for phospho‐lipase A 2 is also possible, because pretreatment of cultures with quinacrine partially blocked arachidonic acid release. Bradykinin‐stimulated arachidonic acid release was decreased in the presence of calcium channel blockers nifedipine or verapamil (50 μ M ), or EDTA (2.5 mM ). The role of calcium was verified further in that accumulation of phosphatidic acid, diacylglycerol, and arachidonic acid was maximally stimulated by treatment with the calcium ionophore A23187 (20 μ M )