Effects of three vasoactive peptides isolated from the plasma of the snake Bothrops jararaca

Incubation of plasma from the snake Bothrops jararaca (BJP) with trypsin generated two hypotensive peptides. The primary structure of the peptides was established for three sequences as: Asn-Pro-Phe-Val-Asp-Ala (fraction 13), Ser-Lys-Pro-Asn-Met-Ser-Asp-Glu-Ser-Leu-Ala-Val-Ala-Ile (fraction 14), Asn-Pro-Phe-Val-Asp-Ala (fraction 15). These peptides display homology with fragments of albumin from Trimeresurus flavoviridis. A bolus intra-arterial injection of the purified or the synthetic peptide produced a strong and sustained vasopressor response in the anaesthetized snake B. jararaca and Wistar rats; this hypotensive effect was also potentiated by captopril, an angiotensin-converting enzyme inhibitor (0.1 mg/kg). The natural concentrations of these peptides in plasma need to be determined and could play a physiological role in snake blood pressure regulation.