High intravascular pressure attenuates vascular dilation responses of small mesenteric arteries in the rat.
BACKGROUND
Alterations in intravascular pressure can affect vascular function and the morphological properties of arteries. Although it has been shown that a transient elevation of blood pressure impairs endothelium-dependent dilation in small arteries, the vascular dilation responses during high intravascular pressure have not yet been investigated.


RESULTS
Using pressure myography, the endothelium-dependent and -independent dilation responses of small mesenteric arteries of rats were examined under 3 different intravascular pressure conditions (50, 80 and 120 mmHg). Endothelium-dependent dilation was evaluated by measuring vasodilator responses to increasing doses of acetylcholine (ACh, 10(-9) to 10(-4) mol/L) or increases in intraluminal flow (7-36 microl/min). Endothelium-independent vasodilator function was examined by using sodium nitroprusside (SNP, 10(-9) to 10(-4) mol/L). Flow-mediated dilation was significantly attenuated at 120 mmHg whereas ACh-induced dilation was progressively decreased with increases in intravascular pressure (at 80 and 120 mmHg). Significant attenuation in the vasodilator response to SNP was also observed at 80 and 120 mmHg.


CONCLUSIONS
Endothelium-dependent and-independent dilation responses are progressively attenuated with acute increases in intravascular pressure.
Gündüz
Filiz
F
Department of Physiology, Faculty of Medicine, Akdeniz University, Antalya, Turkey. fgunduz@akdeniz.edu.tr
Meiselman
Herbert J
HJ
Başkurt
Oğuz K
OK
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000503:physiopathology*; D009213:Myography; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine