Ca2+-antagonistic properties of phospholipase A2 inhibitors, mepacrine and chloroquine.
The effects of putative phospholipase A2 inhibitors mepacrine and chloroquine on membrane ionic currents were studied in intact frog atrial trabeculae. Both agents decreased slow calcium channel current Isi and fast sodium channel current If. Isi was affected twice at least in comparison to If. Half-block of Isi was observed at approximately 10(-6) mol/l mepacrine and at approximately 10(-5) mol/l chloroquine. These effects on transmembrane ionic transport should be considered when using the above agents as phospholipase inhibitors or antiarrhythmic drugs.
Institute of Biological Physics, Academy of Sciences of the USSR, Moscow Region.
A
A
Filippov
G
G
Skatova
V
V
Porotikov
E
E
Kobrinsky
M
M
Saxon
D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors*; D002121:Calcium Channel Blockers; D002738:Chloroquine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D010740:Phospholipases / Q000037:antagonists & inhibitors*; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D011796:Quinacrine / Q000494:pharmacology*; D011895:Rana ridibunda
D002121:Calcium Channel Blockers; D002738:Chloroquine; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D011796:Quinacrine; D002118:Calcium