Cheek TR, Jackson TR, O'Sullivan AJ, Moreton RB, Berridge MJ, Burgoyne RD. Simultaneous measurements of cytosolic calcium and secretion in single bovine adrenal chromaffin cells by fluorescent imaging of fura-2 in cocultured cells.
J Biophys Biochem Cytol 1989;
109:1219-27. [PMID:
2768340 PMCID:
PMC2115761 DOI:
10.1083/jcb.109.3.1219]
[Citation(s) in RCA: 102] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The cytosolic free calcium concentration ([Ca2+]i) and exocytosis of chromaffin granules were measured simultaneously from single, intact bovine adrenal chromaffin cells using a novel technique involving fluorescent imaging of cocultured cells. Chromaffin cell [Ca2+]i was monitored with fura-2. To simultaneously follow catecholamine secretion, the cells were cocultured with fura-2-loaded NIH-3T3t cells, a cell line chosen because of their irresponsiveness to chromaffin cell secretagogues but their large Ca2+ response to ATP, which is coreleased with catecholamine from the chromaffin cells. In response to the depolarizing stimulus nicotine (a potent secretagogue), chromaffin cell [Ca2+]i increased rapidly. At the peak of the response, [Ca2+]i was evenly distributed throughout the cell. This elevation in [Ca2+]i was followed by a secretory response which originated from the entire surface of the cell. In response to the inositol 1,4,5-trisphosphate (InsP3)-mobilizing agonist angiotensin II (a weak secretagogue), three different responses were observed. Approximately 30% of chromaffin cells showed no rise in [Ca2+]i and did not secrete. About 45% of the cells responded with a large (greater than 200 nM), transient elevation in [Ca2+]i and no detectable secretory response. The rise in [Ca2+]i was nonuniform, such that peak [Ca2+]i was often recorded only in one pole of the cell. And finally, approximately 25% of cells responded with a similar Ca2+-transient to that described above, but also gave a secretory response. In these cases secretion was polarized, being confined to the pole of the cell in which the rise in [Ca2+]i was greatest.(ABSTRACT TRUNCATED AT 250 WORDS)
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