モルモット摘出回腸におけるDibenaminのト-ヌスに対する作用機序および薬物収縮抑制機序,とくにCaとの関連

概要

論文の詳細を見る
Dibenamine (DB) produced contraction due to influx and release of Ca in normal medium, whereas it produced relaxation of the K-induced contraction due to depression of the activity of the muscle cell membrane. DB inhibited active influx, passive influx and release of Ca induced by ACh in this order as the concentrations were increased and also inhibited the contraction by histamine selectively as compared with the contractions by ACh, K and Ba, the inhibition of the ACh-, K- and Ba-contractions being almost to the same degree. In addition, DB inhibited to much the same degree the phasic contraction (PC) and tonic contraction (TC) by histamine, whereas it inhibited TC in preference to PC induced by ACh, K and Ba. Irreversible inhibition by DB of ACh-, K- and Ba-induced contractions were protected by Ca, whereas those of histamine. induced contraction were selectively protected by histamine and antihistamine, but not by Ca. These results indicate that the antagonism of DB and its irreversibility against histamine may be due to blockade of the histaminergic receptor, whereas those against ACh, K and Ba may be due to inhibition of the Ca-site. Evidence has been obtained suggesting that the irreversible parallel shift to the right of the log concentrationaction curve of histamine after washout of DB may be due to spare receptors, whereas that of ACh, K or Ba may be due to inhibition of the Ca-site.
社団法人日本薬理学会の論文