title: Vessel-specific rate of vasorelaxation is slower in diabetic rats.
abstract: The rate of adjustment of endothelium-dependent vasorelaxation was examined in the aorta, iliac and femoral arteries of eight control and eight diabetic rats with and without supplementation with vitamin C. Vessels were constricted using 10(-5) M phenylephrine (PE) and relaxed with 10(-4) M acetylcholine (ACh condition) or 10(-4) M ACh plus 10(-4) M vitamin C (ACh + vitamin C condition) in a myography system. Vasorelaxation was modelled as a mono-exponential function using a non-linear regression analysis. The adjustment (τ) of vasorelaxation was faster in control (6.6 ± 3.2 s) compared to diabetic rats (8.4 ± 3.4 s) (p < 0.05). The time-to-steady-state tended to be shorter in control (32.0 ± 13.9 s) compared to diabetic rats (38.0 ± 15.0 s) (p = 0.1). ACh + vitamin C did not speed the vasorelaxation response. The τ for vasorelaxation was shorter in the femoral (6.5 ± 2.7 s) and iliac (6.8 ± 2.5 s) compared to the aorta (9.2 ± 4.2 s) (p < 0.05). The rate of vasorelaxation was greater in the femoral (3.2 ± 1.4%·s(-1)) compared to the iliac (2.0 ± 1.0%·s(-1)) and aorta (1.1 ± 0.4%·s(-1)) in both groups and in the iliac compared to the aorta (p < 0.05) in the control group. In conclusion, the vasorelaxation response was vessel specific with a slower rate of adjustment in diabetic compared to control animals.
authors.affiliation: School of Kinesiology, Western University, London, ON, Canada.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Murias
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Campos
authors.forename: Katharine E
authors.initials: KE
authors.lastname: Hall
authors.forename: Matthew W
authors.initials: MW
authors.lastname: McDonald
authors.forename: C W James
authors.initials: CW
authors.lastname: Melling
authors.forename: Earl G
authors.initials: EG
authors.lastname: Noble
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000503:physiopathology; D001158:Arteries / Q000187:drug effects / Q000503:physiopathology*; D001205:Ascorbic Acid / Q000494:pharmacology; D016022:Case-Control Studies; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005263:Femoral Artery / Q000187:drug effects / Q000503:physiopathology; D007083:Iliac Artery / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology*; D009213:Myography; D017711:Nonlinear Dynamics; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D014815:Vitamins; D010656:Phenylephrine; D000109:Acetylcholine; D001205:Ascorbic Acid