The Effect of Benzodiazepine on Anxiety and Interaction between Benzodiazepine and Histamine in Elevated plus-maze Model of the Rats

It has been suggested that histamine has modulatory influence on anxiety-related behaviors both in animals and humans. On the other hand، GABA (A) receptor modulating drugs such as benzodiazepines have been used to treat anxiety disorders. Co-administration of the aforementioned drugs would be of high interest in terms of anxiety effects. Method & Materials: In the present study، we investigated the anxiety-related effects of individual and combined intraperitoneally administration of histamine and diazepam، a benzodiazepine agent. To do so، anxiolytic indices of Open Arm Times (%OAT) and Open Arm Entries (%OAE) were measured using an elevated plus-maze test of anxiety on rats. Intraperitoneal histamine administration 20 (mg/kg) decreased %OAT، but not locomotor activity، showing an anxiogenic response. Subcutaneous administration of diazepame at dose of 1 mg/kg increased %OAT and %OAE، but not locomotor activity، showing an anxiolytic response. Subcutaneous administration of diazepame، at doses of 1 mg/kg before histamine (20 mg/kg) increased %OAT and %OAE but not locomotor activity، thus showing an anxiolytic response. Our results indicated that the anxiogenic effects induced by histamine in the intraperitoneal could be reversed in the presence of diazepam.