Propranolol a beta adrenergic antagonist, binds with 5-HT1 receptor. 1-(1-naphthyl) piperazine (1-NP) a derivative of quipazine has serotonin antagonist activity at 5-HT2 and agonist activity at 5-HT1 site. In the present study neurochemical and behavioral effects of 1-NP was monitored in saline and propranolol injected rats. 1NP increased locomotor activity in saline as well as in propranolol injected rats. Administration of propranolol also increased locomotor activity and these increases were more enhanced following 1-NP administration. Levels of 5-HT were not altered following the administration of 1NP in saline as well as propranolol injected rats. 5-HT turnover however decreased by the administration of propranolol Adminstration of 1NP decreased 5-HT turnover in saline but not in propranolol injected rats.