Preincubation of synaptosomes in the presence of sodium affects Ca2+ uptake.
Preincubation of synaptosomes in standard physiological medium stimulates 2-fold Ca2+ uptake as compared to non-preincubated synaptosomes. When the sodium concentration in the preincubation medium has been halved, Ca2+ uptake was reduced by approximately 50 percent. The addition of ouabain to the preincubation medium decreases depolarization-stimulated Ca2+ uptake by about 40 percent. A steady-state level of Ca2+ uptake is achieved by synaptosomes preincubated for 0, 5 or 10 min. These findings suggest that Ca2+ uptake might depend on the Na-gradient formed during the preincubation of synaptosomes under control conditions.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D012964:Sodium; D002118:Calcium