Some central effects of indenolol in experimental animals

Indenolol, a relatively new beta-adrenergic blocking drug, was tested for its effect on the central nervous system. The parameters included its effects on spontaneous motor activity, conditioned avoidance response (CAR) acquisition, pentobarbitone hypnosis, amphetamine induced motor excitation, analgesic activity and rectal temperature in experimental animals. Indenolol was found to significantly decrease the spontaneous motor activity in mice and CAR acquisition in rats. It potentiated the pentobarbitone induced hypnosis and antagonized amphetamine induced excitatory behaviour in mice. It did not show a marked analgesic effect of its own but potentiated the analgesia induced by the subanalgesic dose of morphine. It also produced a significant hypothermic effect in mice. All the effects except on CAR acquisition were obtained in the dose of 50-75 mg/kg body weight administered intraperitoneally. It enhanced CAR acquisition in the specific dose of 5 mg/kg. These observations indicate that indenolol possesses an anxiolytic effect similar to that reported for propranolol and some other beta-blocking drugs.