Interactions between essential fatty acid, prostanoid, polyol pathway and nitric oxide mechanisms in the neurovascular deficit of diabetic rats.
Impaired omega-6 essential fatty acid metabolism and exaggerated polyol pathway flux contribute to the neurovascular abnormalities in streptozotocin-diabetic rats. The potential interactions between these mechanisms were examined by comparing the effects of threshold doses of aldose reductase inhibitors and evening primrose oil, alone and in combination, on neurovascular deficits. In addition, high-dose aldose reductase inhibitor and evening primrose oil treatment effects were challenged by co-treatment with the cyclo-oxygenase inhibitor, flurbiprofen, or the nitric oxide synthase inhibitor, NG-nitro-L-arginine. Eight weeks of diabetes caused an 18.9% reduction in sciatic motor conduction velocity (p < 0.001). This was only modestly ameliorated by a 0.1% dietary supplement of evening primrose oil or the aldose reductase inhibitors ZD5522 (0.25 mg.kg-1.day-1 and WAY121 509 (0.2 mg.kg-1.day-1 for the final 2 weeks. However, joint treatment with primrose oil and ZD5522 or WAY121 509 caused marked 71.5 and 82.4% corrections, respectively, of the conduction deficit. Sciatic nutritive blood flow was 43.1% reduced by diabetes (p < 0.001) and this was corrected by 67.8% with joint ZD5522 and primrose oil treatment (p < 0.001). High-dose WAY121 509 (10 mg. kg-1.day-1 and primrose oil (10% dietary supplement) prevented sciatic conduction velocity and nutritive blood flow deficits in 1-month diabetic rats (p < 0.001). However, these effects were abolished by flurbiprofen (5 mg.kg(-1).day-1 and NG-nitro-L-arginine (10 mg.kg-1.day-1) co-treatment (p < 0.001). Thus, the data provide evidence for synergistic interactions between polyol pathway/nitric oxide and essential fatty acid/cyclo-oxygenase systems in the control of neurovascular function in diabetic rats, from which a potential therapeutic advantage could be derived.
Cameron
N E
NE
Department of Biomedical Sciences, University of Aberdeen, Scotland, UK.
Cotter
M A
MA
Hohman
T C
TC
D000083:Acetanilides / Q000494:pharmacology*; D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000378:metabolism / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000378:metabolism / Q000503:physiopathology*; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004921:Erythropoietin / Q000494:pharmacology; D005228:Fatty Acids, Essential / Q000494:pharmacology*; D005480:Flurbiprofen / Q000494:pharmacology; D005632:Fructose / Q000378:metabolism; D007294:Inositol / Q000378:metabolism; D008041:Linoleic Acids; D008297:Male; D009431:Neural Conduction / Q000187:drug effects; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine; D031665:Oenothera biennis; D010938:Plant Oils; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012044:Regression Analysis; D012584:Sciatic Nerve / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology*; D013012:Sorbitol / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology*; D017965:gamma-Linolenic Acid
D000083:Acetanilides; D001786:Blood Glucose; D004042:Dietary Fats, Unsaturated; D004791:Enzyme Inhibitors; D005228:Fatty Acids, Essential; D008041:Linoleic Acids; D010938:Plant Oils; D013450:Sulfones; C091470:WAY 121-509; C090184:ZENECA ZD 5522; D004921:Erythropoietin; D019335:Nitroarginine; D005632:Fructose; D009569:Nitric Oxide; C028498:evening primrose oil; D007294:Inositol; D013012:Sorbitol; D005480:Flurbiprofen; D017965:gamma-Linolenic Acid; D001120:Arginine; D000449:Aldehyde Reductase; D019001:Nitric Oxide Synthase