title: Carbon monoxide does not contribute to vascular tonus improvement in exercise-trained rats with chronic nitric oxide synthase inhibition.
abstract: Carbon monoxide (CO), an end product of heme oxygenase (HO) that is involved in the regulation of vascular tonus, may show a compensatory effect in nitric oxide (NO) deficiency. This study aimed to assess the effect of the HO/CO system on the vascular tone in exercise-trained rats with hypertension induced by chronic NO synthase (NOS) inhibition. Hypertension was induced by N-nitro-l-arginine methyl ester (25 mg/kg/day in drinking water), and exercise training comprised swimming 1 h/day, 5 days/week, for 6 weeks. Systolic blood pressure (BP) was measured weekly using a tail-cuff method. The effects of hypertension and/or exercise-training on the constriction and relaxation responses of the thoracic aorta and resistance arteries of the mesenteric and gastrocnemius vascular beds were evaluated. NOS inhibition produced a gradually developed hypertension, and the magnitude of the increase in BP was significantly attenuated by exercise training. Although phenylephrine (Phe)-induced contraction responses of aorta incubated with an HO-1 inhibitor were reduced in hypertensive animals, there was no difference in the hypertensive-exercise group. However, thoracic aortas in the hypertensive-exercise group exhibited significantly more relaxation in response to a CO donor. There was no change in Phe-induced contraction with or without HO inhibition CO donor relaxation responses in both resistance arteries. These results suggest that the HO/CO system does not contribute to diminishing BP by exercise training in a NOS inhibition-induced hypertension model.
authors.affiliation: Akdeniz University, Faculty of Medicine, Department of Physiology, Antalya, Turkey.
authors.forename: Seher Nasırcılar
authors.initials: SN
authors.lastname: Ülker
authors.affiliation: Near East University, Faculty of Medicine, Department of Physiology, Nicosia, Cyprus.
authors.forename: Günnur
authors.initials: G
authors.lastname: Koçer
authors.affiliation: Akdeniz University, Faculty of Medicine, Department of Physiology, Antalya, Turkey. Electronic address: uksenturk@akdeniz.edu.tr.
authors.forename: Ümit Kemal
authors.initials: ÜK
authors.lastname: Şentürk
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D002248:Carbon Monoxide / Q000378:metabolism*; D002950:Citrate (si)-Synthase / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D008638:Mesenteric Arteries / Q000503:physiopathology; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017208:Rats, Wistar; D014655:Vascular Resistance
chemical_list: D002248:Carbon Monoxide; D019001:Nitric Oxide Synthase; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; C105245:heme oxygenase-2; D002950:Citrate (si)-Synthase; D019331:NG-Nitroarginine Methyl Ester
keywords: Carbon monoxide; Exercise; Heme oxygenase; Hypertension; Nitric oxide synthase