Cardiovascular properties of MS-857, a new and potent cardiotonic agent, on normal and failing hearts.

Abstract

The cardiovascular properties of MS-857 [4-acetyl-1-methyl-7-(4-pyridyl)-5,6,7,8-tetrahydro-3(2H)-isoquinolinone ], a novel cardiotonic agent, were investigated in anesthetized and conscious dogs. MS-857 (1-100 micrograms/kg i.v.) produced a significant and dose-dependent increase in cardiac contractility with relatively small changes in heart rate and blood pressure. This indicates a sizable separation between positive inotropic and other effects of MS-857. Oral administration of MS-857 to conscious dogs (0.1-1 mg/kg) also produced a sustained increase in cardiac contractility in a dose-dependent manner. The total duration of action was longer than 7 h at a dose of 1 mg/kg p.o. There occurred no arrhythmias and no changes in animal behavior. After chronic oral administration, MS-857 completely retained its activities, indicating the lack of tachyphylaxis. In the acute heart failure models induced by either propranolol or pentobarbital, MS-857 reversed the cardiac depressant effects of these drugs. Moreover, MS-857 also significantly improved the pentobarbital-induced heart failure in the heart-lung preparation. MS-857 did not inhibit the Na+, K+-ATPase, but inhibited the phosphodiesterase (PDE) III selectively, both of which were prepared from the dog ventricular muscle. Thus, MS-857 can be characterized as a potent nonsympathomimetic, nonglycoside cardiotonic drug with a selective inhibitory activity on PDE III. The cardiovascular properties revealed by this study strongly suggest that MS-857 will exert a beneficial effect in the treatment of congestive heart failure.

• Authors: M Maruyama, J Kamiya, T Kaiho, T Kobari
• Journal: Journal of cardiovascular pharmacology (J Cardiovasc Pharmacol) Vol. 12 Issue 5 Pg. 579-86 ( 1988) ISSN: 0160-2446 [Print] United States
• PMID: 2468058 (Publication Type: Journal Article)

Chemical References

• Cardiotonic Agents
• Isoquinolines
• Tetrahydroisoquinolines
• MS 857
• Propranolol
• Phosphoric Diester Hydrolases
• Sodium-Potassium-Exchanging ATPase
• Pentobarbital

Topics

• Anesthesia
• Animals
• Cardiotonic Agents (pharmacology)
• Dogs
• Female
• Heart (drug effects)
• Heart Failure (chemically induced, physiopathology)
• Isoquinolines (pharmacology)
• Lung (drug effects)
• Male
• Myocardium (enzymology)
• Pentobarbital
• Phosphoric Diester Hydrolases (blood)
• Propranolol
• Sodium-Potassium-Exchanging ATPase (blood)
• Stereoisomerism
• Tetrahydroisoquinolines