Effect of adrenergic receptor blockers on the cardio-respiratory response to cow's urine concoction in rats.

The influence of alpha and beta adrenoceptor blockers on the cardio-respiratory effects of cow's urine concoction (CUC) in rats was studied. The study showed that phenoxybenzamine abolished the pressor response observed in the untreated animal while propranolol had no effect on blood pressure response. The alpha-blocked animals also developed significant post-injection hypotension. Electrocardiographic abnormalities seen in the control group were ameliorated by beta-blockers but alpha-blockers had no such effect. CUC caused an initial depression of respiration with short apnoeic phases and an increase in pulmonary ventilation. The latter was significantly decreased by alpha and beta adrenoceptor blockers. It was concluded that adrenoceptors play an important role in the cardio-respiratory effects of CUC.