Mn2+ prevents the Ca2+-induced inhibition of ATP synthesis in brain mitochondria.
Uptake of Ca2+ by rat brain mitochondria causes an inhibition of respiratory stimulation by ADP, and the inhibition is relieved upon Na+-induced release of Ca2+ from the mitochondria, in accordance with earlier reports. We show that simultaneous uptake of Ca2+ and Mn2+ results in no inhibition of ADP-stimulated respiration, indicating that Mn2+ prevents the Ca2+-induced inhibition of ATP synthesis, without preventing Ca2+ accumulation in the mitochondria. The results are discussed in relation to a possible involvement of the mitochondrial ATPase-inhibitor protein in the observed effects of Ca2+ and Mn2+.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D008345:Manganese; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002118:Calcium