[Osmotic regulation of furosemide-sensitive K+ (86Rb+) transport in rat brain synaptosomes]

In the rat brain synaptosomes the furosemide-sensitive component of 86Rb+ uptake constituted 30.8% of the total uptake in the medium containing 132 mM Na+. A decrease in the medium tonicity from 310 to 230 mOsm increased the rate of 86Rb+ uptake from 2.38 +/- 0.58 to 7.12 +/- 0.52 nMoles/mg of protein/min.