Estradiol in vitro modulates Na+-dependent Ca2+ uptake by synaptic plasma membrane vesicles of rat brain regions.
Membrane vesicles loaded with [Na+], prepared from synaptosomal plasma membranes (SPM) of whole brains (WB), hippocampi (Hip) and caudate nuclei (NC) of female rats, were used to study Na+ -dependent Ca2+ transport across SPM vesicles under the influence of 17beta-estradiol (E2) in vitro. In concentrations near to physiologic, E2 significantly increased 45Ca2+ uptake by SPM vesicles from all the brain tissues investigated. The maximum increase was observed for WB (21%) and Hip (33%) at 10(-9) mol/l, and for NC (31%) at 5 x 10(-9) mol/l of E2. These results (a) confirm our earlier finding that E2 in vitro modulates Na+-dependent Ca2+ transport across synaptosomal membrane in rat brain regions, and (b) suggest Na+/Ca2+ exchange as principal mechanism of the E2-stimulated Na-dependent Ca2+ uptake by membrane vesicles. The involvement of any ATPases as possible mediators is discussed.
Nikezić
G
G
Laboratory for Molecular Biology and Endocrinology, Vinća Institute for Nuclear Sciences, Belgrade, Serbia, Yugoslavia.
Nedeljković
N
N
Horvat
A
A
Kanazir
D
D
Martinović
J V
JV
D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001921:Brain; D002118:Calcium / Q000378:metabolism*; D002421:Caudate Nucleus; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006624:Hippocampus; D009994:Osmolar Concentration; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013997:Time Factors
D004958:Estradiol; D012964:Sodium; D000251:Adenosine Triphosphatases; D002118:Calcium