Sodium-induced calcium release from mitochondria in brown adipose tissue.
Coupled mitochondria of brown adipose tissue can accumulate Ca2+ if a substrate is present. The Ca2+ is released by addition of 20 mM Na+, but not by addition of K+ or choline +. Energy-dissipating Na+-induced Ca2+ cycling occurs maximally with 20 mM Na+ and 10 microM Ca2+. In brown adipocytes, the Ca2+ ionophore A23187 and the Na+ ionophore monensin increase respiration if substrate is added, and incubation in a low-Na+ buffer decreases norepinephrine-induced respiration. Thus Na+-induced Ca2+ release takes place in brown adipose tissue; released Ca2+ could have a regulatory or thermogenic role or both.
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D004734:Energy Metabolism / Q000187:drug effects; D007476:Ionophores / Q000494:pharmacology; D008647:Mesocricetus; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*
D007476:Ionophores; D012964:Sodium; D002118:Calcium; D009638:Norepinephrine