R Scivoletto

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The response to vasoactive agents of microvessels in situ and large arteries in vitro was compared in normal and alloxan-diabetic rats. Noradrenaline was equally effective in evoking a constrictor response of mesenteric microvessels in normal and diabetic animals. The constrictor response to a standard amount of noradrenaline in such vessels was fully(More)
1 Noradrenaline (NA) evoked a vasoconstrictor response in rat mesenteric microvessels in situ, the latency and nature of which was analogous in normal and alloxan-diabetic animals.2 Histamine and bradykinin (Bk) were capable of antagonizing the response to NA in normal but not in diabetic animals. In contrast, acetylcholine (ACh) was equally effective as an(More)
The response to vasoactive agents of microvessels of the rat was tested in vivo by direct microscopic observation of the exteriorized mesentery and assessment of cutaneous vascular permeability changes with Evans blue. The constrictor response to a standard amount of noradrenaline in mesenteric microvessels was fully antagonized by acetylcholine in normal,(More)
Although female sex hormones may attenuate endothelial dysfunction in spontaneously hypertensive rats (SHR) by increasing endothelium-derived relaxing factors (EDRFs), the influence of ovarian hormones on the generation of endothelium-derived contracting factors (EDCFs) remains unknown. The aim of this study was to evaluate the effect of estrogen and(More)
1. The constrictor response of microvessels to norepinephrine and tyramine, and the dilator response to acetylcholine and papaverine was equivalent in normal and alloxan-induced diabetic rats. 2. Acetylcholine and phentolamine were equally effective as antagonists of the vasoconstrictor action of norepinephrine in both groups of animals. 3. The minimum(More)
In order to choose the best procedure to inactive the endothelium from vascular beds perfused in vitro, we compared four methods: perfusion with sodium deoxycholate 0.3% for 30 sec; 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate 0.3% (CHAPS) for 2.5 min; collagenase 0.2% for 15 min, and distilled water for 10 min, using the mesenteric arterial(More)
To investigate the nature of the arachidonic acid metabolite involved in the altered reactivity of microvessels of two-kidney, one-clip hypertensive rats and the possible contribution of this product to the elevated blood pressure levels found in two-kidney, one-clip hypertension, mesenteric arterioles either perfused in vitro or studied in vivo were used(More)
1. To verify if tolrestat, an aldose reductase inhibitor, corrects the impaired responses of microvessels to histamine and bradykinin in alloxan-diabetic rats, the mesenteric microcirculation was studied in vivo in anaesthetised animals. 2. The impaired responses were corrected by tolrestat 5 mg/kg/day for 7 days p.o. Similar responses to acetylcholine and(More)
Decreased maximal responses to noradrenaline, adrenaline and phenylephrine were observed in aortas isolated from rats pretreated with triiodothyronine and thyroxine for 8 days. In addition, a potent relaxant effect occurred when supramaximal concentrations of noradrenaline and adrenaline, but not of phenylephrine, were used. The relaxant effect was not(More)