Cardiovascular actions of rattlesnake bradykinin ([Val1,Thr 6]bradykinin) in the anesthetized South American rattlesnake Crotalus durissus terrificus

Gina L.J. Galli, Nini Skovgaard, Augusto S. Abe, Edwin W. Taylor, J. Michael Conlon, Tobias Wang

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Incubation of heat-denatured plasma from the rattlesnake Crotalus atrox with trypsin generated a bradykinin (BK) that contained two amino acid substitutions (Arg1 → Val and Ser6 → Thr) compared with mammalian BK. Bolus intra-arterial injections of synthetic rattlesnake BK (0.01-10 nmol/kg) into the anesthetized rattlesnake, Crotalus durissus terrificus, produced a pronounced and concentration-dependent increase in systemic vascular conductance (Psys). This caused a fall in systemic arterial blood pressure (Psys) and an increase in blood flow. Heart rate and stroke volume also increased. This primary response was followed by a significant rise in Psys and pronounced tachycardia (secondary response). Pretreatment with NG-nitro-L-arginine methyl ester reduced the NK-induced systemic vasodilatation, indicating that the effect is mediated through increased NO synthesis. The tachycardia associated with the late primary and secondary response to BK was abolished with propranolol and the systemic vasodilatation produced in the primary phase was also significantly attenuated by pretreatment, indicating that the responses are caused, at least in part, by release of cathecholamines and subsequent stimulation of β-adrenergic receptors. In contrast, the pulmonary circulation was relatively unresponsive to BK.

Original languageEnglish
Pages (from-to)R456-R465
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume288
Issue number2 57-2
DOIs
Publication statusPublished - Feb 2005
Externally publishedYes

Keywords

  • Adrenergic receptor
  • Catecholamines
  • Nitric oxide
  • Reptile
  • Vasoactive kinin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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