This study has been carried out to investigate the augmenting or inhibiting effects of histamine, 5-hydroxytryptamine and their antagonists on the uterine motility. The uterine motility was represented by the magnitude of impulse and the frequency of uterine contraction which was counted by the number of waves on the recording paper. The inhibitory effect of phenoxybenzamine on the response to 5-hydroxytryptamine is the result of drug antagonism. Histamine stimlates or inhibits the motility of smooth muscle through H1 or H2-receptor. The uterine motility was increased through H1-receptor. Histamine induced relaxation by acting through H2-receptor.

To elucidate the physiological characteristics of histamine receptor of the isolated renal artery in dog, effects of various receptor blockers and Ca++ channel blockers on the contractile responses of histamine were investigated in the isolated renal artery of dog. Histamine caused the contraction in the isolated renal artery of dog, and the contractile responses increased between the concentration of 5 x 10** (-6)M and 10** (-2)M in dose-dependent manner. The contractile response induced by histamine (10** (-3)M) was not blocked by pretreatment with atropine (10** (-6)M), phentolamine (10** (-6)M), propranolol (10** (-6)M) or cimetidine (10** (-6)M), but was completely blocked by pretreatment with pyrilamine (10** (-6)M). The contractility induced by histamine (10** (-3)M) was decreased in the Ca++ free medium. The contractile response induced by histamine (10** (-3)M) was decreased in the Ca++ free medium. The contractility induced by histamine (10** (-3)M) was markedly inhibited by pretreatment with papaverine (5x10** (-5)M) or verapamil (5x10** (-5)M). After the pre-contraction induced by norepinephrine (10** (-7)M) or prostaglandin F2 alpha (5x10** (-6)M), the contractile response induced by the additional treatment of histamine (10** (-3)M) was markedly increased compared with that of histamine (10** (-3)M) alone

To validate the physiological properties of the histamine receptors of ileal smooth muscle in dog, the effect of adrenergic, cholineric and H-receptor antagonists on the responses of ileal smooth muscle strips to histamine were investigated. Histamine caused the contraction of ileal smooth muscle and the contractile responses increased between the concentration of histamine (10-7M and 10-5 M) with dosedependent manner in dog. The shorter the treatment interval of histamine, the lower the contractile activity until the treatment interval extended to 40 minutes