'Snapshot' images of localized Ca²⁺ influx into patch-clamped chromaffin cells were captured by using a recently developed pulsed-laser imaging system. Transient opening of voltage-sensitive Ca²⁺ channels gave rise to localized elevations of Ca²⁺ 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 colocalized. These results provide functional support for the idea that secretion occurs from 'active zone'-like structures in neuroendocrine cells.