Effects of calcium antagonists on (Na+ + K+)-ATPase, Mg2+-ATPase and Ca2+-ATPase activities of rat cortical synaptosomes.
1. The effects of 11 calcium antagonists on (Na+ + K+)-ATPase, Mg2+-ATPase and Ca2+-ATPase activities of rat cortical synaptosomes were studied. 2. All the calcium antagonists studied had inhibitory effects on ouabain-sensitive (Na+ + K+)-ATPase, Mg2+-ATPase and Ca2+-ATPase activities in synaptosomes at high concentrations (10 or 100 microM). 3. Calcium antagonists such as trifluoperazine, flunarizine and cinnarizine had inhibitory effects on Ca2+-ATPase activity at low concentrations (1-10 microM). 4. Trifluoperazine and La3+ had inhibitory effects on Mg2+-ATPase activity at low concentration (1 microM). 5. Our results suggest that most of the calcium antagonists studied have little effects on neuronal (Na+ + K+)-ATPase, Mg2+-ATPase and Ca2+-ATPase activities at therapeutic dose ranges (1 microM or lower).
Chiang
D H
DH
Institute of Neurosciences, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China.
Wei
J W
JW
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology*; D066298:In Vitro Techniques; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013574:Synaptosomes / Q000201:enzymology*
D002121:Calcium Channel Blockers; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase