Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1937941 | Biochemical and Biophysical Research Communications | 2007 | 6 Pages |
Abstract
Exocytosis and endocytosis are Ca2+-dependent processes. The contribution of high-voltage activated Ca2+ channels subtypes to exocytosis has been thoroughly studied in chromaffin cells. However, similar reports concerning endocytosis are unavailable. Thus, we studied here the effects of blockers of L (nifedipine), N (Ï-conotoxin GVIA) and P/Q (Ï-agatoxin IVA) Ca2+ channel on Ca2+ currents (ICa), Ca2+ entry (QCa), as well as on the changes in membrane capacitance (Cm) in perforated-patch voltage-clamped bovine adrenal chromaffin cells. Using 500-ms pulses to 0 or +10Â mV, given from a holding potential of â80Â mV and 2Â mM Ca2+ we found that Ï-conotoxin GVIA affected little the exo-endocytotic responses while Ï-agatoxin IVA markedly blocked those responses. However, nifedipine blocked little exocytosis but almost completely inhibited endocytosis. We conclude that L-type Ca2+ channels seem to be selectively coupled to endocytosis.
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Authors
Juliana Martins Rosa, Antonio M.G. de Diego, Luis GandÃa, Antonio G. GarcÃa,