Flow-induced dilatation in isolated resistance arteries from control and streptozotocin-diabetic rats.
Acetylcholine-induced vasodilatation is impaired in animal models of insulin-dependent diabetes mellitus (IDDM), and may result from altered nitric oxide synthesis or release. The response to intraluminal flow, a more physiologically relevant stimulus for nitric oxide release, is unknown. This study examined flow-induced responses in isolated resistance arteries from male Sprague-Dawley control and streptozotocin-diabetic (45 mg/kg i.v., 4 week duration) rats. Mesenteric arteries (4-5th order) were dissected and cannulated on a pressure myograph (mean internal diameter +/- SEM at 40 mmHg, control 223 +/- 8, n = 9 vs diabetic 239 +/- 12 microm, n = 8, NS). Arteries were preconstricted with noradrenaline (1 micromol/l) and intraluminal pressure raised and maintained at 80 mmHg. Luminal flow was raised in incremental steps (0-1.27 microl/s). Arteries from control animals dilated to flow while arteries from diabetic animals constricted (% change in internal diameter +/- SEM at 0.79 microl/s: control 13.46 +/- 6.52, n = 9 vs diabetic -7.44 +/- 3.38%, n = 8; p < 0.005). Incubation with N(omega)-nitro-L-arginine methyl ester (0.1 mmol/l) abolished flow responses in arteries from controls but not from diabetic rats. In conclusion, impaired flow-induced nitric oxide-mediated vasodilatation may contribute to vascular disease in IDDM.
Tribe
R M
RM
Department of Obstetrics and Gynaecology, UMDS, St. Thomas' Hospital, London, UK.
Thomas
C R
CR
Poston
L
L
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000098:blood supply*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D013314:Stress, Mechanical; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine