Altered arachidonic acid-mediated responses in the perfused kidney of the streptozotocin-induced diabetic rat.
Using perfused kidneys isolated from age-matched controls and streptozotocin (STZ)-induced diabetic rats, we investigated the effects of arachidonic acid (AA) on perfusion pressure in the presence of methoxamine. AA elicited a transient contraction followed by a sustained relaxation in each group. The amplitude of contraction was smaller in the diabetic group than in the control group, whereas the amplitude of the sustained relaxation was greater in the former than in the latter group. In the diabetic group, the AA-induced sustained relaxation was completely inhibited by indomethacin [cyclooxygenase (COX) inhibitor], SKF525A [cytochrome P450 (CYP450) inhibitor], or clotrimazole (epoxygenase inhibitor), but not by furegrelate [thromboxane A(2) (TXA(2))-synthase inhibitor], SQ29548 (TXA(2)-receptor antagonist), or baicalein [lipoxygenase (LOX) inhibitor]. In the diabetic kidney, more-or-less additive inhibitions of the AA-induced relaxation were seen when indomethacin was given with either SKF525A or clotrimazole. These results suggest that in the STZ-induced diabetic perfused kidney, vasorelaxant metabolites derived from AA (probably COX and/or CYP450 metabolites) are increased, and may serve to regulate vascular tone.
Kamata
Katsuo
K
Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan. kamata@hoshi.ac.jp
Hosokawa
Masao
M
Matsumoto
Takayuki
T
Kobayashi
Tsuneo
T
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism / Q000494:pharmacology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000209:etiology; D004195:Disease Models, Animal; D018450:Disease Progression; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007668:Kidney / Q000098:blood supply*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010477:Perfusion; D011335:Proadifen / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D013311:Streptozocin
D016861:Cyclooxygenase Inhibitors; D065607:Cytochrome P-450 Enzyme Inhibitors; D016718:Arachidonic Acid; D013311:Streptozocin; D011335:Proadifen; D007213:Indomethacin