Characterization of Pardaxin-Induced Dopamine Release from Pheochromocytoma Cells: Role of Calcium and Eicosanoids

摘要: Pardaxin, an excitatory neurotoxin, induced dopamine release from pheochromocytoma (PC12) cells both in the presence and absence of extracellular calcium ([Ca]o). In calcium, nifedipine, L-type channel blocker, did not affect release, whereas 1,2-bis (2-aminophenoxy) ethane N,N, N'N'-tetra-acetic acid (BAPTA), a chelator cytosolic dantrolene, blocker intracellular stores, inhibited only partially (30-40%) pardaxin-induced release. [Ca]o, BAPTA dantrolene were ineffective. Pardaxin stimulated arachidonic (AA) cascade PC12 independently [Ca]o. The phospholipase inhibitors mepacrine bromophenacyl bromide AA Dopamine by pardaxin also was blocked lipoxygenase nordihydroguaiaretic acid, esculetin, 2-(12-hydroxydodeca-5, 10-diynyl)-3,5,6-trimethyl-1,4-benzoquinone. Under these conditions, parallel reduction 5-hydroxyeicosatetranoic observed. Suppression A2 more pronounced calcium-free medium. These results indicate involvement pathway suggest use this toxin as novel pharmacological tool for investigating mechanism calcium-independent neurotransmitter