ABSTRACT
The present work describes the discovery of novel series of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepine-5-ylidene)acetamide derivatives as arginine vasopressin (AVP) V(2) receptor agonists. By replacing the amide juncture in YM-35278 with a direct ring connection gave compound 10a, which acts as a V(2) receptor agonist. These studies provided the potent, orally active non-peptidic V(2) receptor agonists 10a and 10j.
Subject(s)
Arginine Vasopressin/metabolism , Benzazepines/chemical synthesis , Receptors, Vasopressin/agonists , Animals , Antidiuretic Agents/chemical synthesis , Antidiuretic Agents/chemistry , Antidiuretic Agents/pharmacology , Benzazepines/chemistry , Benzazepines/pharmacology , CHO Cells , Cricetinae , Cricetulus , Male , Molecular Structure , Radioligand Assay , Rats , Rats, Wistar , Receptors, Vasopressin/metabolism , Structure-Activity RelationshipABSTRACT
Activation of the volume-regulated anion channels (VRAC) is considered to be involved in arrhythmia, but it has not yet been fully elucidated because of the lack of its high affinitive and selective compounds. A newly synthesized compound, YM-198313 (sodium 4-({[2-(methylthio)benzyl]amino}-5-[(1-phenylethyl)thio]isothiazol-3-olate), strongly inhibited VRAC in HeLa cells with an IC50 of 3.03+/-0.05 microM. However, YM-198313 weakly affected both the Ca2+-activated Cl- channels in HTC cells and the cAMP-activated Cl- channels in T84 cells, demonstrating that this compound is selective for VRAC among Cl- channels. At 10 microM, YM-198313 almost completely (100+/-7.8%) inhibited the VRAC current in guinea pig atrial myocytes. However, at the same concentration, YM-198313 showed little inhibitory effect on the cardiac cation currents in ventricular myocytes. We believe that YM-198313 is a potent and selective VRAC inhibitor, therefore, it should be use to clarify the role VRAC plays in arrhythmia.
Subject(s)
Anti-Arrhythmia Agents/pharmacology , Benzyl Compounds/pharmacology , Chloride Channel Agonists , Thiazoles/pharmacology , Animals , Chloride Channels/physiology , Guinea Pigs , HeLa Cells , Heart Atria/drug effects , Heart Atria/metabolism , Humans , Male , Osmolar ConcentrationABSTRACT
The pharmacological properties of YM-57029 [4-[4-(4-carbamimidoylphenyl)-3-oxopiperazin-1-yl]piperidino]acetic acid monohydrochloride trihydrate), a novel glycoprotein IIb/IIIa antagonist were examined in this study. YM-57029 inhibited fibrinogen binding to purified glycoprotein IIb/IIIa, 1000-fold more potently than the tetrapeptide arginine-glycine-aspartic acid-serine (RGDS). YM-57029 concentration-dependently inhibited ADP-, collagen- and high shear stress-induced platelet aggregation, strongly inhibited ATP release from platelets activated by ADP, and enhanced deaggregation of ADP-induced platelet aggregates. In a pro-aggregatory activity study, RGDS or SC-54701A ((S)-3-[3-[(4-amidinophenyl)carbamoyl]propionamido]-4-pentynoic acid monohydrochloride) caused prominent small aggregate formation. At a higher concentration, RGDS induced medium and large size aggregates, and SC-54701A induced medium aggregates. In contrast, YM-57029 produced only a few small and no larger size aggregates. Ex vivo ADP-induced platelet aggregation and platelet retention to collagen-coated plastic beads were dose-dependently inhibited by YM-57029 after intravenous bolus injection in guinea pigs. YM-57029 produced dose-dependent antithrombotic effects in carotid artery thrombosis and arterio-venous shunt thrombosis models in guinea pigs at 10 and 30 microg/kg, respectively. At these doses, YM-57029 prolonged template bleeding time. These results suggest that YM-57029 is a potent glycoprotein IIb/IIIa antagonist which has less pro-aggregatory effect. It may be a promising antiplatelet agent for thromboembolic diseases, and a good prototype for developing an orally active compound.
