Modifications by hypoxia and drug treatment of cerebral ATPase plasticity.
The plasticity of synaptosomal non-mitochondrial ATPases was evaluated in cerebral cortex from 3-month-old normoxic rats and rats subjected to either mild or severe intermittent normobaric hypoxia [12 hr daily exposure to N2:O2 (90:10 or 91.5:8.5) for four weeks]. The activities of Na+, K(+)-ATPase, low- and high-affinity Ca(2+)-ATPase, Mg(2+)-ATPase, and Ca2+,Mg(2+)-ATPase were assayed in synaptosomes and synaptosomal subfractions, namely synaptosomal plasma membranes and synaptic vesicles. The evaluations were performed after a 4-week treatment with saline (controls) or alpha-adrenergic agents (delta-yohimbine, clonidine), a vasodilator compound (papaverine), and an oxygen-partial pressure increasing agent (almitrine). These treatments differently changed the adaptation to chronic intermittent hypoxia characterized by a decrease in the activity of Na+,K(+)-ATPase, Ca2+,Mg(2+)-ATPase, and high-affinity Ca(2+)-ATPase, concomitant with a modification in the activity of Mg(2+)-ATPase supported in a different way by the enzymatic forms located into the synaptosomal plasma membranes and synaptic vesicles.
Benzi
G
G
Institute of Pharmacology-State University of Pavia, Italy.
Gorini
A
A
Ghigini
B
B
Arnaboldi
R
R
Villa
R F
RF
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D015765:Almitrine / Q000494:pharmacology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology*; D003000:Clonidine / Q000494:pharmacology*; D002534:Hypoxia, Brain / Q000378:metabolism*; D007700:Kinetics; D010208:Papaverine / Q000494:pharmacology*; D051381:Rats; D012016:Reference Values; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013570:Synaptic Membranes / Q000201:enzymology; D013572:Synaptic Vesicles / Q000201:enzymology; D013574:Synaptosomes / Q000187:drug effects / Q000201:enzymology*; D015016:Yohimbine / Q000494:pharmacology*
D015016:Yohimbine; D015765:Almitrine; D010208:Papaverine; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D003000:Clonidine