[Osmotic regulation of the sodium pump in rat brain synaptosomes].
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.
Mongin
A A
AA
Aksentsev
S L
SL
Rakovich
A A
AA
Okun'
N M
NM
Konev
S V
SV
Orlov
S N
SN
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002414:Cations, Monovalent; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D009995:Osmosis; D010042:Ouabain / Q000378:metabolism; D051381:Rats; D012413:Rubidium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D002414:Cations, Monovalent; D003571:Cytochalasin B; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D003078:Colchicine
Osmoticheskaia reguliatsiia natrievogo nasosa v sinaptosomakh golovnogomozga krys.