title: Hypotensive effects of YM430, a 1,4-dihydropyridine derivative, in spontaneously hypertensive rats and renal hypertensive dogs.
abstract: The hypotensive effects of YM430 (4(((S)-2-hydroxy-3-phenoxypropyl)amino)butyl methyl 2,6-dimethyl-((S)-4-(m-nitrophenyl))-1,4-dihydropyridine-3,5-dicarboxyla te) were evaluated in hypertensive animals. In conscious spontaneously hypertensive rats (SHR), single oral administration of YM430 (10-100 mg/kg) produced a dose-dependent decrease in mean blood pressure (MBP) with slight reflex tachycardia. The hypotensive effect of YM430 reached its maximum about 2 hr after dosing and lasted for over 10 hr. Importantly, the beta 1-adrenoceptor blocking activity of YM430 had a similar time course to that of its calcium entry blocking activity. In conscious normotensive dogs (NTD: 1-10 mg/kg, p.o.), YM430 decreased MBP without reflex tachycardia, and inhibited isoproterenol (ISO)-induced tachycardia in a dose-dependent manner. In conscious renal hypertensive dogs (RHD: 0.3-3 mg/kg, p.o.), YM430 also produced a sustained hypotensive effect. Furthermore, on repeated oral administration to conscious SHR and NTD, YM430 caused a long-lasting hypotensive effect. This hypotensive activity and inhibition of ISO-induced tachycardia showed neither tolerance, augmentation nor rebound. In conclusion, YM430 has a long-lasting hypotensive effect and behaves as a hybrid compound, combining calcium entry blocking and beta 1-adrenoceptor blocking activities in vivo. In addition, the degree of the blocking activities of YM430 remains nearly constant in the long-term after oral administration.
authors.affiliation: Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Ibaraki, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Shibasaki
authors.forename: K
authors.initials: K
authors.lastname: Takizawa
authors.forename: W
authors.initials: W
authors.lastname: Uchida
authors.forename: T
authors.initials: T
authors.lastname: Takenaka
mesh_terms: D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003243:Consciousness; D004285:Dogs; D004334:Drug Administration Schedule; D006973:Hypertension / Q000188:drug therapy*; D006977:Hypertension, Renal / Q000188:drug therapy; D008297:Male; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; C106124:YM 430; D009543:Nifedipine