ISSN:
1573-6881
Keywords:
Mitochondrial calcium
;
inorganic phosphate
;
membrane permeability transition
;
calcium transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract The role of inorganic phosphate as inhibitor of mitochondrial membrane permeability transition was studied. It is shown that in mitochondria containing a high phosphate concentration, i.e., 68 nmol/mg, Ca2+ did not activate the pore opening. Conversely, at lower levels of matrix phosphate, i.e., 38 nmol/mg, Ca2+ was able to induce subsequent pore opening. The inhibitory effect of phosphate was apparent in sucrose-based media, but it was not achieved in KCl media. The matrix free Ca2+ concentration and matrix pH were lowered by phosphate, but they were always higher in K+-media. In the absence of ADP, phosphate strengthened the inhibitory effect of cyclosporin A on carboxyatractyloside-induced Ca2+ efflux. Acetate was unable to replace phosphate in the induction of the aforementioned effects. It is concluded that phosphate preserves selective membrane permeability by diminishing the matrix free Ca2+ concentration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022483018482
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