title: Effects of nicorandil and its congeners on musculature and vasculature of the dog trachea in situ.
abstract: In anesthetized dogs, the tracheal vascular bed in situ was perfused with arterial blood through the cannulated cranial thyroid arteries. The effects of nicorandil, a coronary vasodilator, and its congeners (SG-212, GS-209 and SG-103; in which the nitroxy group of nicorandil was substituted for other groups) on the tracheal musculature and vasculature were examined. All drugs were injected intra-arterially. Nicorandil (10-300 micrograms), SG-212 (100 micrograms-3 mg), SG-209 (100 micrograms-3 mg) and SG-103 (100 micrograms-3 mg) all produced a decrease in tracheal tone elevated by neostigmine (tracheal dilatation) and an increase in tracheal blood flow (tracheal vasodilatation). Relative potencies of these effects were in the descending order: nicorandil greater than SG-212 = SG-209 = SG=103 in producing tracheal vasodilatation. These results suggest that nicorandil would also be a potential bronchodilator and that the nitrate site in nicorandil plays a role in potentiating the pharmacological activity of congeners of nicorandil.
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D012039:Regional Blood Flow / Q000187:drug effects; D014132:Trachea / Q000098:blood supply / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D009536:Niacinamide; D020108:Nicorandil; C035664:SG 103; C035662:SG 212; C035663:SG 209