CONVERSION TO NEUROCYTE OF CULTURED ADRENAL CHROMAFFIN CELLS AND ITS MOLECULAR PHARMACOLOGICAL STUDY

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Adrenal chromaffin cells are regarded as a model of catecholamine containing neurons and are suitable for study of stimulus-secretion coupling. In this strdy, therefore, bovine adrenal chromaffin cells in culture were used.Condition of cell cultureBovine adrenal chromaffin cells which are cultured for a few days areused in recent research in this project, long term cultured these cells are necessary to convert to neurocyte. We succeeded these cells culture for several weeks (at least 3 weeks).Morphological studyEffects of glucocorticoids and nerve growth factors on form of cultured bovine adrenal chromaffin cells were investigated. Nerve growth factors stimulate formation of axons on these cells at 2 weeks culture, but glucocorticoids do not. Therefore, the conversion to neurocyte of cultured adrenal chromaffin cells is suggested.Pharmacological studyIn adrenal chromaffin cells, secretory stimulations cause an increase in the intracellular free Ca^<2+> level([Ca^<2+>]i) originating from intracellular pools and extracellular spaces, leading to stimulation of catecholamine secretion and activation of catecholamine biosynthesis. After stimulations, the increased[Ca^<2+>]i)should rapidly return to the resting level for response to a subsequent stimulation. Bradykinin, PACAP and histamine stimulate extracellular Na^+-dependent Ca^<2+> efflux from cultured bovine adrenal chromaffin cells. We are investigating the effects of nerve growth factors on these peptides-induced Ca^<2+> efflux from the cells.