Colocalization of Calcium Entry and Exocytotic Release Sites in AdrenalChromaffin Cells

摘要

Snapshot images of localized Ca2+ influx into patch-clamped chromaffin cells werecaptured using a recently developed pulsed-laser imaging system. Transient opening of voltage-sensitive Ca2+ channels gave rise to localized elevations of Ca that had the appearance of either hotspots or partial rings found immediately beneath the plasma membrane. When the Ca2+ imaging technique was employed in conjunction with flame-etched carbon-fiber electrodes to spatially map the release sites of catecholamines, it was observed that the sites of Ca2+ entry and catecholamine release were co-localized. These results provide functional support for the idea that secretion occurs from active zone-like structures in neuroendocrine cells.