Nicardipine dose dependently reduces the effect of equinatoxin II on coronary flow in isolated rat heart.
Equinatoxin II (EqT II) decreases coronary flow in guinea-pig and rat heart. It increases cytosolic Ca2+ activity and is supposed to form cation selective membrane pores. In the present study we tried to evaluate the influence of the L-type Ca2+ channel antagonist nicardipine upon the vasoconstrictory effect of EqT II on coronary vessels in isolated heart of the rat. Coronary flow was measured during the experiment. Ten min after bolus injection of EqT II the coronary flow decreased to 17.2 +/- 4.3% in experiments without nicardipine, and to 39.4 +/- 4.5% in the group with 0.1 microM nicardipine (p < 0.05). Our results indicate the possibility that L-type Ca2+ channels could be involved in the effects of EqT II on coronary flow in the rat heart.
Kuhar
C G
CG
Department of Pharmacology and Experimental Toxicology, Medical Faculty, Ljubljana, Slovenia.
Bunc
M
M
Drevensek
G
G
Budihna
M V
MV
Suput
D
D
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000502:physiology; D003064:Cnidarian Venoms / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D004347:Drug Interactions; D066298:In Vitro Techniques; D008297:Male; D009529:Nicardipine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D003064:Cnidarian Venoms; D014662:Vasoconstrictor Agents; C012307:equinatoxin; D009529:Nicardipine