Vasoconstrictor actions of delta8- and delta9-tetrahydrocannabinol in the rat

J Pharmacol Exp Ther. 1976 Mar;196(3):649-56.


Cardiovascular effects of delta8- and delta9-tetrahydrocannabinol (THC) were studied after systemic intravenous administration and intra-arterial administration into a perfused vascular bed in the urethane-anesthetized rat. Intravenous administration of delta8- and delta9-THC produced dose-related transient increases in blood pressure followed by more prolonged hypotensive responses and bradycardia. Intra-arterial administration of delta8- and delta9-THC into the perfused hindquarters of the rat produced an increase in perfusion pressure indicative of vasoconstriction. The vasoconstrictor response to the cannabinoids corresponded temporally to a similar response produced by i.a. norepinephrine and was in contrast to the more prolonged vasoconstrictor responses produced by vasopressin. Phentolamine, in a dose which reduced the vasoconstrictor effect of norepinephrine by 90%, significantly reduced the response to i.a. delta9-THC while having no effect on the actions of i.a. vasopressin. It was demonstrated that reserpine pretreatment significantly reduced vasoconstrictor actions of i.a. tyramine and delta9-THC but did not alter the responses to norepinephrine. These data suggest that delta8- and delta9-THC have peripheral vasoconstrictor activity in the rat which may be mediated, in part, through a tyramine-like action on adrenergic nerve terminals.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Blood Pressure / drug effects
  • Cannabis / pharmacology*
  • Dronabinol / pharmacology*
  • Heart Rate / drug effects
  • Hindlimb / blood supply
  • Male
  • Rats
  • Regional Blood Flow / drug effects
  • Reserpine / pharmacology
  • Time Factors
  • Vasoconstrictor Agents / pharmacology*


  • Adrenergic alpha-Antagonists
  • Vasoconstrictor Agents
  • Dronabinol
  • Reserpine