Effect of beta-adrenergic antagonists on experimentally induced drinking in female rats

The nonspecific beta-adrenergic antagonist d,l propranolol, the specific beta 1-adrenergic antagonist atenolol, and the specific beta 2-adrenergic antagonist butoxamine were administered intraperitoneally (IP) to ovariectomized female rats in order to determine the role of beta-adrenergic receptors in drinking. D,l propranolol and atenolol administered at doses of 6, 12, and 18 mg/kg significantly attenuated the one-hour water intakes of rats administered angiotensin II (200 micrograms/kg, SC) and the water intakes of rats deprived of water for 24 hours. D propranolol, which has little beta-adrenergic blocking ability, administered at doses of 6 and 12 mg/kg, and butoxamine, administered at doses of 25 and 35 mg/kg, had no significant effects on the water intakes of angiotensin II treated or water deprived rats. Regardless of the dose, d,l propranolol, atenolol, and butoxamine failed to significantly alter the water intakes of rats administered 1.0 M NaCl (10 ml/kg, IP) The results provide evidence that beta 1-adrenergic receptors, but not beta 2-adrenergic receptors, are involved in mediating the increased water intakes induced by angiotensin II and water deprivation. On the other hand the increased water intake due to administration of hypertonic saline does not appear to mediated by beta-adrenergic receptors.