The adrenergic regulation of the cardiovascular system in the South American rattlesnake, Crotalus durissus

Comp Biochem Physiol A Mol Integr Physiol. 2007 Nov;148(3):510-20. doi: 10.1016/j.cbpa.2007.06.420. Epub 2007 Jun 30.


The present study investigates adrenergic regulation of the systemic and pulmonary circulations of the anaesthetised South American rattlesnake, Crotalus durissus. Haemodynamic measurements were made following bolus injections of adrenaline and adrenergic antagonists administered through a systemic arterial catheter. Adrenaline caused a marked systemic vasoconstriction that was abolished by phentolamine, indicating this response was mediated through alpha-adrenergic receptors. Injection of phentolamine gave rise to a pronounced vasodilatation (systemic conductance (G(sys)) more than doubled), while injection of propranolol caused a systemic vasoconstriction, pointing to a potent alpha-adrenergic, and a weaker beta-adrenergic tone in the systemic vasculature of Crotalus. Overall, the pulmonary vasculature was far less responsive to adrenergic stimulation than the systemic circulation. Adrenaline caused a small but non-significant pulmonary vasodilatation and there was tendency of reducing this dilatation after either phentolamine or propranolol. Injection of phentolamine increased pulmonary conductance (G(pul)), while injection of propranolol produced a small pulmonary constriction, indicating that alpha-adrenergic and beta-adrenergic receptors contribute to a basal regulation of the pulmonary vasculature. Our results suggest adrenergic regulation of the systemic vasculature, rather than the pulmonary, may be an important factor in the development of intracardiac shunts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic alpha-Antagonists / administration & dosage
  • Adrenergic beta-Antagonists / administration & dosage
  • Animals
  • Aorta, Thoracic / metabolism
  • Blood Pressure
  • Cardiovascular System / drug effects
  • Cardiovascular System / metabolism*
  • Crotalus / metabolism*
  • Epinephrine / metabolism*
  • Heart Rate
  • Injections, Intra-Arterial
  • Phentolamine / administration & dosage
  • Propranolol / administration & dosage
  • Pulmonary Artery / metabolism
  • Pulmonary Circulation
  • Receptors, Adrenergic, alpha / metabolism*
  • Receptors, Adrenergic, beta / metabolism*
  • Regional Blood Flow
  • Research Design
  • Stroke Volume
  • Vasoconstriction* / drug effects
  • Vasodilation* / drug effects


  • Adrenergic alpha-Antagonists
  • Adrenergic beta-Antagonists
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic, beta
  • Propranolol
  • Epinephrine
  • Phentolamine