A comparative study on the sensitivity of erythrocytes from different vertebrate species (avian, mammalian and reptilian) to the hemolytic action caused by cardiotoxin isolated from Naja naja atra venom was carried out. Cardiotoxin was able to induce direct hemolysis in washed erythrocytes from several animals, except for llama. The EC50 values from hemolysis of the most sensitive (cat) and the most resistant (snake) animal varied approximately tenfold. According to the cell behavior, it was possible to characterize four types of behavior: The first was observed in cat, horse and human cells; the second in rat, rabbit and dog erythrocytes; and the third only in llama erythrocytes, which were resistant to cardiotoxin concentrations up to 300 µg/ml. Finally, avian and reptilian erythrocytes were more resistant to cardiotoxin III-induced hemolysis than those of the mammalian species.

Blood samples were collected from 180 healthy specimens of the South American rattlesnake, Crotalus durissus terrificus, in captivity. All animals were in good clinical condition. Normal biochemical reference values were established for the following: total proteins, albumin, globulins, uric acid, creatinine, urea, glucose, triglycerides, cholesterol, total lipids, calcium, phosphorus, potassium, sodium, chloride, magnesium, GOT (AST), GPT (ALT), and alkaline phosphatase (ALP). Samples were obtained by venipuncture of the ventral tail vein. Values were compared with published data for Boidae, Elapidae, and Viperidae.