| Autor: |
Westerink, R. H. S., Rook, M. B., Beekwilder, J. P., Wadman, W. J. |
| Předmět: |
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| Zdroj: |
Journal of Neurochemistry; Oct2006, Vol. 99 Issue 2, p628-640, 13p, 1 Color Photograph, 3 Charts, 6 Graphs |
| Abstrakt: |
Calbindin-D28K is suggested to play a postsynaptic role in neurotransmission and in the regulation of the intracellular Ca2+ concentration. However, it is still unclear whether calbindin-D28K has a role in the regulation of exocytosis, either as Ca2+ buffer or as Ca2+ sensor. Amperometric recordings of catecholamine exocytosis from wild-type and calbindin-D28K knockout mouse chromaffin cells reveal a strong reduction in the number of released vesicles, as well as in the amount of neurotransmitter released per fusion event in knockout cells. However, Ca2+ current recordings and Ca2+ imaging experiments, including video-rate confocal laser scanning microscopy, revealed that the intracellular Ca2+ dynamics are remarkably similar in wild-type and knockout cells. The combined results demonstrate that calbindin-D28K plays an important and dual role in exocytosis, affecting both release frequency and quantal size, apparently without strong effects on intracellular Ca2+ dynamics. Consequently, the possibility that calbindin-D28K functions not only as a Ca2+ buffer but also as a modulator of vesicular catecholamine release is discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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