Haemodynamic rebound phenomena after abrupt cessation of propranolol therapy in portal hypertensive rats.
The haemodynamic effect of sudden termination of propranolol therapy was studied in sham-operated and portal hypertensive rats. All animals were injected with propranolol (20 mg/kg/day) or saline i.p. for 10 days, then had an isoproterenol infusion test performed 48 h or 72 h after cessation of injections. The dose of isoproterenol required to increase the heart rate by 50 beats/min (CD50), was significantly lower in both sham-operated and portal hypertensive rats at 48 h after propranolol withdrawal. Maximum chronotropic response (Rmax), was significantly higher only in portal hypertensive rats at 48 h after propranolol withdrawal. These results show the existence of a transient beta-adrenergic hypersensitivity state following propranolol withdrawal in normal and portal hypertensive rats.
D000818:Animals; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006975:Hypertension, Portal / Q000188:drug therapy*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011433:Propranolol / Q000009:adverse effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*
D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D007545:Isoproterenol