Tight mitochondrial control of calcium and exocytotic signals in chromaffin cells at embryonic life.
Pflugers Arch
; 467(12): 2589-601, 2015 Dec.
Article
em En
| MEDLINE
| ID: mdl-26254593
ABSTRACT
Calcium buffering by mitochondria plays a relevant physiological function in the regulation of Ca(2+) and exocytotic signals in mature chromaffin cells (CCs) from various adult mammals. Whether a similar or different role of mitochondrial Ca(2+) buffering is present in immature CCs at early life has not been explored. Here we present a comparative study in rat embryonic CCs and rat mother CCs, of various physiological parameters that are known to be affected by mitochondrial Ca(2+) buffering during cell activation. We found that the clearance of cytosolic Ca(2+) transients ([Ca(2+)]c) elicited by high K(+) was 7-fold faster in embryo CCs compared to mother CCs. This strongly suggests that at embryonic life, the mitochondria play a more significant role in the clearance of [Ca(2+)]c loads compared to adult life. Consistent with this view are the following results concerning the transient suppression of mitochondrial Ca(2+) buffering by protonophore FCCP, in embryonic CCs compared to mother CCs (i) faster and greater inactivation of inward calcium currents, (ii) higher K(+)-elicited [Ca(2+)]c transients with 25-fold faster clearance, (iii) higher increase of basal catecholamine release and (iv) higher potentiation of K(+)-evoked secretion. These pronounced differences could be explained by two additional features (embryo versus mother CCs) (a) slower recovery of mitochondrial resting membrane potential after the application of a transient FCCP pulse and (b) greater relative density of the mitochondria in the cytosol. This tighter control by the mitochondria of Ca(2+) and exocytotic signals may be relevant to secure a healthy catecholamine secretory response at early life.
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MEDLINE
Assunto principal:
Células Cromafins
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Sinalização do Cálcio
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Exocitose
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article