Effects of La+++, Mn++ and ruthenium red on Mg-Ca-ATPase activity and ATP-dependent Ca-binding of the synaptic plasma membrane.
The effects of La+++, Mn++ and ruthenium red (R.R.) on Ca-uptake of synaptic plasma membranes (S.P.M.) were investigated. La+++ (0.1 mM), Mn++ (0.2 mM) and R.R. (0.1 mM) selectively inhibited Mg-Ca-ATPase but did not significantly affect Mg-ATPase activity. The apparent Ki values of La+++, Mn++ and R.R. for Mg-Ca-ATPase were 0.05, 0.06 and 0.03 mM, respectively. La+++, Mn++ and R.R. did not affect Ca-uptake at concentrations which strongly inhibited Mg-Ca-ATPase activity. These results indicate that Ca-uptake by S.P.M. differ from that by sarcoplasmic reticulum.
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology*; D008274:Magnesium; D008345:Manganese / Q000494:pharmacology*; D051381:Rats; D012428:Ruthenium / Q000494:pharmacology*; D012430:Ruthenium Red / Q000494:pharmacology*; D013569:Synapses / Q000166:cytology*
D012430:Ruthenium Red; D008345:Manganese; D007811:Lanthanum; D012428:Ruthenium; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium