Effect of Tityus discrepans Venom on the Coagulation Mechanism.
D'Suze, G.1; Brazón, J.1; Sevcik, C.1; Guerrero; B.; Ojeda; A. and Arocha, Piñango C.M.2.
Laboratorio de Neurofarmacología Celular1, Laboratorio de Fisiopatología2, Instituto Venezolano de Investigaciones Científicas (IVIC) Apartado 21827, Caracas 1020-A, Venezuela.
Previous studies in our laboratory have shown that the effect of Tityus discrepans venom on rabbit lungs involves disseminated microthrombi. We decided to study the effect of the venom on the coagulation mechanism in vitro. Lyophilized venom pools were dissolved in 20 mM CH3-COOH at pH 4.85. Protein separation by molecular exclusion was achieved by means of high-performance liquid chromatography (HPLC) (Protein-PakTM 125 column, 7.8 x 300 mm, Waters) eluting at 0.5 ml/min with 20 mM CH3-COOH at pH 4.85. Six fractions (Fl through FVI) were separated, with retention times ranging from 12.83 to 30.97 minutes. We studied the effect of the whole venom (WV) of the six isolated fractions (IF) and of the pooled isolated fractions (PIF) on purified fibrinogen, plasma re-calcification time (PRT), protrhombin time (PT), and partial tromboplastin time (PTT) in the presence and absence of CaCI2 (0.025 M). Whole venom had no effect on purified fibrinogen. WV and Fl reduced PRT, which was prolonged by Fractions II, III, IV, and VI. PTT was extended in a dose-dependent manner by WV, IF, and FVI. Fractions III, IV, and V produced a slight prolongation of PTT. The effects produced by IF on PTT are different from either the effects produced by WV or PIF. The WV prolonged PT. All these effects are calcium dependent. The results show that Td venom contains pro- and anti-coagulant components separable by HPLC. This work was partially financed by CONICIT - Grant:S1-95000722 (GD'S).
Publication Dates
-
Publication in this collection
08 Oct 2002 -
Date of issue
Dec 2001
