Comparison of effects of diabetes mellitus on an EDHF-dependent and an EDHF-independent artery.
The hypothesis tested in this study is that diabetes has a different impact on an artery in which endothelium-dependent responses derive from both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) compared with responses in which NO predominates and EDHF is absent. The streptozotocin-treated rat model of diabetes was used, and the arteries were mounted on a wire myograph. In mesenteric arteries depolarized and constricted with phenylephrine, acetylcholine evoked hyperpolarization (31 +/- 2 mV) and complete relaxation; these responses were attributed to EDHF and NO. In femoral arteries, acetylcholine evoked a small, NO-mediated hyperpolarization (5 +/- 1 mV) and incomplete relaxation. Bradykinin evoked NO-dependent responses in mesenteric arteries. Whereas diabetes significantly impaired the EDHF-dependent hyperpolarization and relaxation in mesenteric arteries, NO-dependent responses in femoral and mesenteric arteries were preserved. 1-Ethyl-2-benzimidazolinone evoked hyperpolarization and relaxation in mesenteric arteries, and this was impaired in diabetes. In conclusion, NO-dependent responses are preserved in diabetes, whereas endothelial responses-dependent upon EDHF appear to be impaired. The putative channels responsible for mediating the EDHF response may be altered in diabetes.
Wigg
S J
SJ
Department of Physiology, Monash University, Victoria 3800, Australia.
Tare
M
M
Tonta
M A
MA
O'Brien
R C
RC
Meredith
I T
IT
Parkington
H C
HC
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001685:Biological Factors / Q000502:physiology*; D001920:Bradykinin / Q000494:pharmacology; D002317:Cardiovascular Agents / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004594:Electrophysiology; D004730:Endothelium, Vascular / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005263:Femoral Artery / Q000187:drug effects / Q000503:physiopathology*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000503:physiopathology*; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D014661:Vasoconstriction; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
D001685:Biological Factors; D002317:Cardiovascular Agents; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; C067410:endothelium-dependent hyperpolarization factor; D000109:Acetylcholine; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin