Studies on the Physiological Properties of the Histamine Receptor of Ileal Smooth Muscle in Dog

개 회장 평활근에 있어서 Histamine Receptor의 생리적 특성에 관한 연구

To validate the physiological properties of the histamine receptors of ileal smooth muscle in dog, the effects of adrenergic-, cholineric-, and H-receptor antagonists on the responses of ileal smooth muscle strips to histamine were investigated. The results were summarized as follows; 1. Histamine caused the contraction of ileal smooth muscle and the contractile responses were increased between the concentration of histamine $10^{-7}M$ and $10^{-5}M$ with dose-dependent manner in dog. 2. The shorter the treatment interval of histamine, the lower the contractile activity until the treatment interval extended to 40 minutes. 3. The contractile response induced by histamine was completely blocked by the pre treatment with a $H_1$-receptor blocker, chlorpheniramine and not by the pretreatment with a $H_2$-receptor blockers cimetidine. 4. The contractile response induced by histamine was not blocked by the pretreatment with a cholinergic receptor blocker, atropine. 5. The contractile response induced by histamine was not blocked by the pretreatment with an ${\alpha}$-adrenergic receptor blocker, phenoxybenzamine, or a ${\beta}$-adrenergic receptor blocker, propranolol. From these results, it was suggested that the contraction induced by histamine was elicited through $H_1$-receptor on the ileal smooth muscle in dog.