Alloxan diabetes blocks noradrenergic tachyphylaxis in the isolated rabbit kidney--effects of insulin.
Normal and alloxan treated diabetic rabbit kidneys were perfused with Krebs-Henseleit solution in a non-recirculating system and the effects of norepinephrine (NOR) 10(-6)M were tested by infusion of this drug for three subsequent periods of 20 min each, with an interval of 10 min for drug wash-out. In the control kidneys the infusion of NOR promoted an intense vasoconstriction, which was less intense during the second and the third periods. This was known as tachyphylaxis. In contrast to the controls, kidneys from diabetic animals did not show tachyphylaxis to NOR, but when insulin was added to the perfusate, tachyphylaxis appeared. Normal kidneys perfused with hyperosmolar solutions show, as in controls, the same phenomenon. The data presented here demonstrate a defect of adrenergic vascular receptors in alloxan treated kidneys, which can be acutely reversed by insulin. These facts are of importance for the understanding of the vascular disease in diabetes.
Costa e Forti
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Unidade de Pesquisas Clínicas, Centro de Ciências da Saúde, Fortaleza Ceará, Brazil.
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005260:Female; D007328:Insulin / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects*; D008297:Male; D009638:Norepinephrine / Q000502:physiology*; D011817:Rabbits; D013618:Tachyphylaxis / Q000502:physiology*
D007328:Insulin; D009638:Norepinephrine