Proceedings of the National Academy of Sciences · 1995 · 133 citations · 31 references
Life SciencesBiophysicsCell BiologyCell SignalingExocytosisNeuroendocrinologyCalcium SignalingCellular ImagingExocytosis In Endocrine CellsIntracellular Calcium SignalingNeuroendocrine PhysiologyNeurotransmitter ReleaseActive Zone OrganizationCalcium ImagingCarbon ElectrodesCatecholamine SecretionChromaffin Cell ExocytosisIntracellular Calcium ImagingIntracellular Calcium ReleaseVoltage-gated Channels
"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.
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