title: Differential chronotropic and inotropic effects of 2-nicotinamidoethyl nitrate (SG-75) in the dog isolated atrium.
abstract: 1. The chronotropic and inotropic effects of the anti-anginal agent SG-75 (2-nicotinamidoethyl nitrate) and 1-verapamil were investigated in isolated blood-perfused canine atrial preparations. The compounds were administered via the cannulated sinus node artery. 2. SG-75 induced a selective negative inotropic as opposed to a chronotropic effect. Verapamil showed no selective negative chronotropic or inotropic activity. 3. Effects of SG-75 and 1-verapamil on the frequency-force relationship were studied. SG-75 produced a uniform depression of the developed tension at all frequencies tested which the depression with 1-verapamil was greater at higher than at lower frequencies.
mesh_terms: D000787:Angina Pectoris / Q000188:drug therapy*; D000818:Animals; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D009566:Nitrates / Q000494:pharmacology*; D012849:Sinoatrial Node / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
chemical_list: D009566:Nitrates; D009536:Niacinamide; D020108:Nicorandil; D014700:Verapamil