Synaptosomal (Ca2+-Mg2+)-ATPASE activity modulation by cyclic AMP.
Dibutyryl cyclic AMP, in a concentration-dependent manner, increased synaptosomal (Ca2+-Mg2+)-ATPase activity, but in synaptic plasma membranes lacked any effect. The maximal enzyme activity in synaptosomes was increased by 38%, leaving unaltered the extrasynaptosomal Ca2+ concentration necessary to reach it. In the presence of 5 microM cyclic AMP, cyclic AMP-dependent protein kinase increased (30%) maximal (Ca2+-Mg2+)-ATPase activity in synaptic plasma membranes, but the apparent affinity for Ca2+ was not modified. This effect was partially inhibited (60%) by a cyclic AMP-dependent protein kinase inhibitor. The data suggest that synaptosomal (Ca2+-Mg2+)-ATPase activity is modulated by a cyclic AMP-dependent phosphorylation reaction.
Rodriguez
R
R
Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Autónoma de Barcelona, Spain.
Toledo
A
A
Sabrià
J
J
Rodriguez
J
J
Blanco
I
I
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000032:analysis*; D002118:Calcium / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D000242:Cyclic AMP / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D011494:Protein Kinases / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000201:enzymology*
D000242:Cyclic AMP; D011494:Protein Kinases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium