| Autor: |
Cheek, Timothy R., O'Sullivan, Antony J., Moreton, Roger B., Berridge, Michael J., Burgoyne, Robert D. |
| Zdroj: |
FEBS Letters; January 1990, Vol. 266 Issue: 1 p91-95, 5p |
| Abstrakt: |
The effect of caffeine on catecholamine secretion and intracellular free Ca 2+concentration ([Ca 2+] 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 [Ca 2+] ithat was independent of external Ca 2+. This rise in [Ca 2+] itriggered little secretion. Single cell measurements of [Ca 2+] ishowed that most cells responded with a large (> 200 nM) rise in [Ca 2+] i, whereas a minority failed to respond. The latter, whose caffeine-sensitive store was empty, buffered a Ca 2+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 Ca 2+homeostasis rather than in triggering exocytosis. |
| Databáze: |
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