Effects of Ca2+ entry blockers on kainate-induced changes in extracellular amino acids and Ca2+ in vivo.
The effect of organic Ca2+ channel blockers and Co2+ on kainate-induced changes in 45Ca2+ efflux and amino acid release was studied in the rabbit hippocampus with the dialysis-perfusion technique. Administration of 1 mM kainate caused a transient, 50% drop of extracellular Ca2+. This effect was insensitive to 100 microM flunarizine or verapamil, 10 microM nimodipine, and 6 mM CoCl2. The organic Ca2+ entry blockers did not significantly influence kainate-induced changes in extracellular amino acids, whereas Co2+ affected both basal and kainic acid stimulated release of amino acids. These results indicate that kainate-regulated Ca2+ ionophores differ from Ca2+ channels in peripheral tissues in terms of sensitivity to Ca2+ entry inhibitors.
Lazarewicz
J W
JW
Medical Research Centre, Polish Academy of Sciences, Warsaw.
Lehmann
A
A
Hamberger
A
A
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003035:Cobalt / Q000494:pharmacology*; D005444:Flunarizine / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007608:Kainic Acid / Q000494:pharmacology*; D009553:Nimodipine / Q000494:pharmacology; D011817:Rabbits; D014700:Verapamil / Q000494:pharmacology
D000596:Amino Acids; D002121:Calcium Channel Blockers; D003035:Cobalt; D009553:Nimodipine; D014700:Verapamil; C018021:cobaltous chloride; D005444:Flunarizine; D007608:Kainic Acid; D002118:Calcium