TY - JOUR
T1 - Flow induces dilatation in the femoral artery of uraemic rats but constriction in control rats
AU - Savage, T
AU - Tribe, R M
AU - Yaqoob, M M
PY - 2001
Y1 - 2001
N2 - Background. Pressure and flow are recognized as important modulators of vascular tone. In mildly uraemic rats, myogenic tone is increased in the femoral artery in the absence of hypertension compared with healthy control rats, but the effect of flow in the same experimental model remains unknown. Subjects and methods, Twelve male Wistar rats were rendered uraemic (U) by 5/6th nephrectomy or were concurrently sham operated as controls (C). After 8 weeks, isolated femoral arteries were mounted on a flow myograph, pressurized at 80 mmHg, and constricted by 40-50% of the lumen internal diameter (i.d.) by L-phenylephrine (1-10 mu mol/l). Flow was initiated (0-207 mul/min) in six steps every 5 min and changes in i.d. recorded. N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (0.1 mmol/l) and 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) (1 mu mol/l) were applied extraluminally and the how protocol repeated. Results, The baseline pre-constricted at 80 mmHg i.d. was significantly smaller in the U (U 255 +/- 21 mum Its C 365 +/- 36 mum, P <0.03). At all steps, flow elicited a dilatation in the U and a constriction in the C (U+ 24 +/- 8% vs C-17+/-5%. Pm vs U + L-NAME & ODQ 240 +/- 11 mum, P = n.s.). Furthermore, in the U there was no significant blunting to dilatation during flow (+9+4%). Conclusions, Flow elicited a constriction in controls, but a marked dilatation in uraemic roots which was not entirely nitric oxide dependent. These results suggest that other mediators such as prostacyclin or endothelium-dependent hyperpolarizing factor, or changes in the vascular smooth muscle may contribute to flow-induced dilatation in mild experimental uraemia.
AB - Background. Pressure and flow are recognized as important modulators of vascular tone. In mildly uraemic rats, myogenic tone is increased in the femoral artery in the absence of hypertension compared with healthy control rats, but the effect of flow in the same experimental model remains unknown. Subjects and methods, Twelve male Wistar rats were rendered uraemic (U) by 5/6th nephrectomy or were concurrently sham operated as controls (C). After 8 weeks, isolated femoral arteries were mounted on a flow myograph, pressurized at 80 mmHg, and constricted by 40-50% of the lumen internal diameter (i.d.) by L-phenylephrine (1-10 mu mol/l). Flow was initiated (0-207 mul/min) in six steps every 5 min and changes in i.d. recorded. N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (0.1 mmol/l) and 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) (1 mu mol/l) were applied extraluminally and the how protocol repeated. Results, The baseline pre-constricted at 80 mmHg i.d. was significantly smaller in the U (U 255 +/- 21 mum Its C 365 +/- 36 mum, P <0.03). At all steps, flow elicited a dilatation in the U and a constriction in the C (U+ 24 +/- 8% vs C-17+/-5%. Pm vs U + L-NAME & ODQ 240 +/- 11 mum, P = n.s.). Furthermore, in the U there was no significant blunting to dilatation during flow (+9+4%). Conclusions, Flow elicited a constriction in controls, but a marked dilatation in uraemic roots which was not entirely nitric oxide dependent. These results suggest that other mediators such as prostacyclin or endothelium-dependent hyperpolarizing factor, or changes in the vascular smooth muscle may contribute to flow-induced dilatation in mild experimental uraemia.
UR - http://www.scopus.com/inward/record.url?scp=0034975867&partnerID=8YFLogxK
U2 - 10.1093/ndt/16.6.1156
DO - 10.1093/ndt/16.6.1156
M3 - Article
SN - 1460-2385
VL - 16
SP - 1156
EP - 1162
JO - Nephrology, Dialysis, Transplantation
JF - Nephrology, Dialysis, Transplantation
IS - 6
ER -