Effect of venom from Bitis nasicornis (rhinoceros horned viper) on isolated rabbit aortic strips.
Venom from B. nasicornis, but not from Bitis arietans, Echis carinatus or Cerastes cerastes, produced an irreversible contraction of the isolated aortic strip that was slow in onset, increased with time, and reached maximum in about 10-15 min. The contraction was not inhibited by pretreatment with atropine, yohimbine, phentolamine, cyproheptadine or indomethacin, however, it was blocked by incubation in a Ca2+-free solution and was partially blocked by incubation with the Ca2+ channel blockers verapamil and nifedipine. It is concluded that B. nasicornis venom may act by increasing the Ca2+ influx into smooth cells, thus causing an increase in intracellular Ca2+ concentration and hence a contraction of the aortic strip.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001285:Atropine / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D003533:Cyproheptadine / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010646:Phentolamine / Q000494:pharmacology; D011817:Rabbits; D014757:Viper Venoms / Q000494:pharmacology*; D015016:Yohimbine / Q000494:pharmacology
D014757:Viper Venoms; D015016:Yohimbine; D003533:Cyproheptadine; D001285:Atropine; D002122:Calcium Chloride; D007213:Indomethacin; D010646:Phentolamine