title: Mechanisms underlying the coronary vasodilation in the isolated perfused hearts of rats submitted to one week of high carbon monoxide exposure in vivo.
abstract: We examined the possible mechanisms for carbon monoxide (CO)-induced effects in hearts isolated from Wistar rats exposed for 1 wk to 530 ppm CO. They were treated by daily intraperitoneal injections of either methylene blue (10 mg/kg), glibenclamide (3 mg/kg), or apamin (125 nmol/kg), known to inhibit vasodilatory mechanisms. Hearts were excised, cannulated, and retrogradely perfused through the coronary artery, using the Langendorff method with a constant perfusion pressure. After stabilization, we investigated the degree of resistance to an in vitro transient global low-flow ischemia. One-week CO exposure induced a significant increase in hematocrit and a cardiomegaly, which were not affected by any of these drugs. An enhancement of coronary flow was observed concomitantly with a decrease in ischemic contracture after CO exposure. However, no improvement of contractile recovery was noted. Since methylene blue did not interact with the CO effects, a cGMP signaling pathway can be excluded. On the contrary, as glibenclamide and to a greater extend apamin blocked the vasodilatory effects of CO, we conclude that K+ channels may be involved in these CO effects.
authors.affiliation: Laboratoire de Préconditionnement et de Remodelage du Myocarde, UFR Sciences, Angers Cedex, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Barbé
authors.forename: Annie
authors.initials: A
authors.lastname: Rochetaing
authors.forename: Paul
authors.initials: P
authors.lastname: Kreher
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000494:pharmacology*; D005260:Female; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006400:Hematocrit; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D009924:Organ Culture Techniques; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D015221:Potassium Channels; D002248:Carbon Monoxide