بررسی اثر آگونیست و آنتاگونیست های مختلف گیرنده هیستامینی بر هماهنگی حرکتی موش صحرایی در تست Rota rod

Background and purpose: Sedation is regarded as a common side effect of most antihistamines, and limits the clinical utility of classical antihistaminic agents, while newer antihistamines are nonsedating. Çonsidering the importance of this phenomenon in the present study, the role of different histamine receptor mechanisms in mediating the sedation were investigated in rat rota rod test. Materials and methods: The integrity of motor coordination on the basis of the endurance time of the rats on the rotating rod, with speed of 16 r.p.m. was assessed. The endurance time was measured before and after drugs treatment. Results: intracerebroventricular (i.c.v) or intraperitoneal injection of HTMT (10 μg/rat) or diphenhydramine( 20, 30 and 40 mg/kg), but not dexchlorpheniramine reduced endurace time of the rat rota rod test. The histamine H2 receptor agonist, dimaprit (30 mg/kg, i.p.) but not antagonists such as famotidine (20-40 mg/kg, i.p.) and ranitidine (20-40 mg/kg, i.p.) decreased the endurance time in the rota rod test. The histamine H3 receptor agonist, imetit (50 mg/kg, i.p.) but not thioperamide (5and 10 mg/kg, i.p) produced a motor impairment in the rota rod test. The dose of 5 mg/kg, i.p. of thioperamide significantly antagonized the motor impairment induced by imetit. Çonclusion: These results suggest that the histamine H3 receptor mechanism may be involved in the modulation of sedation.