Cardiovascular Responses to Bothrops alternatus (Urutu) Snake Venom in Anesthetized Dogs

Abstract

The cardiovascular responses to Bothrops alternatus snake venom in anesthetized dogs were investigated. Venom (0.3 mg/kg, i.v.) markedly decreased arterial blood pressure, coronary perfusion pressure, and cardiac output (CO) after 5 min, with progressive recovery of the first two parameters to pre-venom levels after 3 h; CO showed little recovery. There was an abrupt, sustained decrease in left and right ventricular systolic work and stroke volume but no significant changes in heart rate, electrocardiogram, and pulmonary hemodynamics; systemic vascular resistance increased from 1 h onwards. A venom dose of 1 mg/kg produced more pronounced cardiovascular alterations, with a progressive decrease to death. There were no significant changes in blood gas (pO(2), pCO(2), HCO(3), SBC, and SBE) and metabolic (pH, lactate, glucose, creatine kinase activity, Na(+), and K(+)) parameters, although there was a transitory increase in plasma lactate dehydrogenase 2 min after the lower venom dose. There were no cardiac histological alterations, but microaneurysms and epithelial desquamation were seen in renal tubules. Circulating venom concentrations (determined by ELISA) decreased rapidly after administration, but venom was still detectable after 4 h. These results show that in dogs, B. alternatus venom produces marked hypotension and a direct cardiac action, with few metabolic alterations.

Preclinical Evaluation of the Efficacy of Antivenoms for Snakebite Envenoming: State-of-the-Art and Challenges Ahead

“…Examples are: (a) Cardiovascular alterations: Some studies have monitored the effects of venoms on the mean arterial blood pressure after i.v. injection of venoms [80,81]. Alternatively, the increments in the blood lactic acid concentration might be used to monitor the increment in anaerobic metabolism as a consequence of reduced blood flow and ischemia in tissues [80].…”