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THE INHIBITORY ACTION OF TWO THROMBIN INHIBITORS (TI‐189 AND TI‐233) ON THE CONTRACTILE RESPONSES TO 5‐HYDROXYTRYPTAMINE AND PROSTAGLANDIN ENDOPEROXIDE ANALOGUE (U‐44069) IN ISOLATED VASCULAR STRIPS
Author(s) -
HO WILLIAM K.W.,
NAKAO K.,
SHIBATA S.
Publication year - 1980
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1980.tb10952.x
Subject(s) - inhibitory postsynaptic potential , prostaglandin , chemistry , papaverine , medicine , basilar artery , endocrinology , antagonism , aorta , contraction (grammar) , histamine , pharmacology , receptor
1 Two arginine derivatives that were developed as thrombin inhibitors (TI‐189 and TI‐233) selectively inhibited the 5‐hydroxytryptamine (5‐HT)‐induced contraction of rabbit aortic strips in a competitive manner. The pA 2 values of TI‐189 and TI‐233 were 5.24 ± 0.21 and 6.23 ± 0.32 respectively. 2 Even at 10 −4 m they had no inhibitory effect on the contractile response to noradrenaline (NA), histamine, prostaglandin E 2 (PGE 2 ), PGF 2α , arachidonic acid or potassium in rabbit aortic strips. 3 In dog basilar and coronary arterial strips and also in rat fundus, both agents inhibited the 5‐HT response in a non‐competitive manner. 4 At 10 −5 m , TI‐233 but not TI‐189 antagonized effects of NA and KC1 in the dog basilar and coronary arteries. 5 These arginine derivatives decreased the contractile responses induced by a prostaglandin endoperoxide analogue (U‐44069) in rabbit aorta and in dog basilar and coronary arteries but there was no evidence for competitive antagonism. 6 These results indicate that the arginine derivatives are competitive antagonists selective for 5‐HT receptors in rabbit aorta.