1.
Biofizika
; 37(5): 950-6, 1992.
Article
in Russian
| MEDLINE
| ID: mdl-1335292
ABSTRACT
Effect of medium osmolarity on 3H-ouabain binding and the rate of ouabain-sensitive 86Rb+ transport in the rat brain synaptosomes was studied. A decrease in tonicity to 230 mOsm increases both parameters indicating the activation of the sodium pump upon synaptosome swelling. The effect is retained in the absence of inside-oriented Na+ gradient, i. e. a rise in Na(in) is not responsible for hypoosmotic activation. Colchicine (5mM) decreased and cytochalasin B (40 microM) increased the ouabain binding. In the presence of cytochalasin B the inhibition of binding observed under hypotonic conditions was shifted to higher osmolarity values. It is suggested that volume regulation of the sodium pump is controlled by the cytoskeleton elements.