Rs. Konya et Rc. Elliott, THE CORONARY VASOCONSTRICTOR ACTION OF EXTRACT-IV FROM THE DAHLIA SEA-ANEMONE TEALIA-FELINA L, Toxicon, 34(2), 1996, pp. 277-282
Extract IV, a partially purified preparation of the toxin from the sea
anemone Tealia felina, produced marked bradycardia and arrhythmias in
the rat in vivo. In the Langendorff rat heart preparation perfused at
constant pressure extract IV (0.0224 AU/ml) reduced the force of cont
raction by 81.3 +/- 7.2%, n = 6, and the coronary flow by 82.0 +/- 4.7
%, n = 5. When the preparation was perfused at constant flow rate, ext
ract IV (0.072 AU/ml) increased the coronary circulation resistance fr
om 3.76 +/- 1.09 (control) to 36.94 +/- 12.26 mm Hg/ml/min. The force
of contraction was also markedly reduced. The extract produced bradyca
rdia in preparations perfused at constant pressure but not in those pe
rfused at constant flow rate. The extract did not affect isolated atri
a preparations. It was concluded that the bradycardia produced in vivo
and in preparations perfused in vitro at constant pressure was probab
ly secondary to the coronary vasospasm produced, which could contribut
e to the cardiotoxicity of the extract.