A Comparative Study On The Effects Of Some Antihistaminics Centerally Administered In Rabbits

The present work dealed with studying effects ofintravenous and intracerebroventricular injection ofhistamine, tripelennamine (Hl-antagonists) and cimetidine(H2-antagonists) on blood pressure, E.C.G pattern, heartrate , respiratory rate , serurn e1eet ro1ytes 1eve1 name1ysod i urn , potass i urn and ca1ciurn . A1soeffect sonc1osi ve ran d .kidney functions had been involved to specify the role of drugs on these organs. Tests were carried using adultconscious rabbits. Results from the present work can be summarized as follows:Effect on blood pressure:Histamine (100 ~g) intravenously injected resulted in a non significant fall in blood pressure for half an hourbefore returning tothenormal value, while I.C.V injection by the same dose resulted in long lasting hypertension and this may be attributed to interaction with catecholamin-ergicpathways in the brain. Statistical analysis revealed non significant difference between intravenous and I.C.V data despite observed contrast results.Tripelennamine (2.5 mg/kg) injected I.V resulted in a significan t. rise in blood pressure which was long lastinghypertension, while I.C.V injection by the same dose resulted in a slighthypertension.Statistically non