Author/Editor     Bunc, Matjaž
Title     Kardiovaskularni učinki ekvinatoksina II
Type     monografija
Place     Ljubljana
Publisher     Medicinska fakulteta
Publication year     1999
Volume     str. 67
Language     slo
Abstract     Equinatoxin II is one of three isotoxins isolated from the sea anemone Actinia equina (L.). The cause of death of experimental animals after i.v. application of the toxin was atributed to the cardiorespiratory failure and the hemolytic activity of the toxin. Although different authors reported that lowering of coronary flow should be responsible for the cardiotoxic effects of the toxin, the exact mechanism of the toxin action stands still obscure. In in vivo experiments where ECG, respiratory activity and serum electrolytes were monitored, it was shown that the direct effects of the toxin are also responsible for the lethal effects of the toxin after i. v. application of lethal doses. In rat and pig Langendorff's preparation the dose-response dependent decrease of coronary flow was shown. In both heart models of hearts the toxin provoked comparable effects on the coronary flow. The maximal effect of the toxin was observed at the dose 1 nmol EqT II/100 g of rat heart where the coronary flow dropped to 8,2 +- 3,9 % of control value, and at the dose 0,5 nmol EqT II/100 g of pig heart where coronary flow dropped to 9,8 +- 2,5 % of control value. In isolated rat hearts decrease of the coronary flow after addition of the toxin depended on extracellular concentration of calcium. In isolated pig hearts nicardipine dose dependently lowered the effect of the toxin on the coronary flow. For explanation of the exact mechanism of the toxin action on the coronary flow I performad experiments on isolated pig epicardial coronaries. The contractions of rings of coronaries were measured by mechano electric transducer. The contractions of coronary rings were dose dependent; below 1 nM the toxin caused no measurable changes of the rings tension, the maximal effect of the toxin was observed at 100 nM of the toxin. Nicardipine dose dependently diminised the constrictory effect caused by the toxin. (Abstract truncated at 2000 characters.)
Descriptors     RATS, WISTAR