[Changes in the intensity of the fluorescence of potential-sensitive fluorescent probes in the active transport of Ca2+ in the fragmented sarcoplasmic reticulum].

The dependence of fluorescence intensity changes of potential-sensitive fluorescent probes 3,3'-dipropyl-2,2'-thyodicarbocianine and 1-anilino-8-naphtalenesulphonae on the ATP concentration during Ca2+ transport in fragmented SR of the rabbit skeletal muscle has been studied. An increase in the accumulation of Ca2+ in the SR vesicles caused by ATP is accompanied by an increase in the fluorescence intensity of the potential-sensitive probes. These fluorescence changes are related neither to ATP or Ca2+ effect but are coupled with cation accumulation inside the vesicles since they are not observed in the presence of either EGTA or triton X-100 or in the absence of Mg2+. The results obtained prove the membrane potential generation in SR in the course of ATP-dependent Ca2+ transport.