| Autor: |
Cheek, Timothy R., O'Sullivan, Antony J., Moreton, Roger B., Berridge, Michael J., Burgoyne, Robert D. |
| Zdroj: |
FEBS Letters; June 1990, Vol. 266 Issue: 1-2 p91-95, 5p |
| Abstrakt: |
The effect of caffeine on catecholamine secretion and intracellular free Ca2+concentration ([Ca2+]i) in bovine adrenal chromaffin cells was examined using single fura‐2‐loaded cells and cell populations. In cell populations caffeine elicited a large (∼200 nM) transient rise in [Ca2+]ithat was independent of external Ca2+. This rise in [Ca2+]itriggered little secretion. Single cell measurements of [Ca2+]ishowed that most cells responded with a large (> 200 nM) rise in [Ca2+]i, whereas a minority failed to respond. The latter, whose caffeine‐sensitive store was empty, buffered a Ca2+load induced by a depolarizing stimulus more effectively than those whose store was full. The caffeine‐sensitive store in bovine chromaffin cells may be involved in Ca2+homeostasis rather than in triggering exocytosis. |
| Databáze: |
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