Stimulation of the Na+/K+ pump activity during electrogenic uptake of acidic amino acid transmitters by rat brain synaptosomes.
Addition of D-aspartate, a substrate for the high-affinity transport of acidic amino acid transmitters, to suspensions of rat brain synaptosomes increased the rate of O2 consumption, uptake of 86Rb, and transport of 2-[3H]deoxyglucose. Stimulation of all three processes was abolished in the presence of ouabain. D-Aspartate had no effect on respiration in the medium in which NaCl was replaced by choline chloride. The ratio of the ouabain-sensitive increase in 86Rb uptake to that in O2 consumption was 12 to 1, which gives a calculated 86Rb(K+)/ATP of 2. It is concluded that electrogenic, high-affinity transport of sodium-D-aspartate into synaptosomes stimulates the activity of the Na+/K+ pump through an increase in [Na+]i.
Erecińska
M
M
Department of Pharmacology, University of Pennsylvania, School of Medicine, Philadelphia 19104-6084.
D000596:Amino Acids / Q000493:pharmacokinetics*; D000818:Animals; D001224:Aspartic Acid / Q000493:pharmacokinetics; D001921:Brain / Q000166:cytology*; D003847:Deoxyglucose / Q000493:pharmacokinetics; D008297:Male; D018377:Neurotransmitter Agents / Q000493:pharmacokinetics*; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000493:pharmacokinetics; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*
D000596:Amino Acids; D018377:Neurotransmitter Agents; D001224:Aspartic Acid; D003847:Deoxyglucose; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium