We have examined the effects of pre-hepatic portal hypertension on the responsiveness of aorta from Wistar and Sprague-Dawley rats. Rats were made portal hypertensive by creating a calibrated portal vein stenosis, or sham operated. In rat aorta, there was no significant difference between portal hypertensive and sham-operated animals in the contractile potency of KCl, noradrenaline or phenyleph...

Oxidative stress may increase production of superoxide and nitric oxide, leading to formation of prooxidant peroxynitrite to cause vascular dysfunction. Having found nitrotyrosine residues, a marker of peroxynitrite action, in placental vessels of preeclamptic and diabetic pregnancies, we determined whether vasoreactivity is altered in these placentas and treatment with peroxynitrite produces v...

The relations among hypertensive response, oxidative stress, and mitogen-activated protein kinase (MAPK) in cardiovascular tissues have not been fully established. We investigated the involvement of reactive oxygen species on changes in the hemodynamics and cardiovascular MAPKs activities induced by acutely administered angiotensin II (Ang II) in conscious normotensive rats with or without trea...

The peptide hormone relaxin has striking effects on the vascular system. Specifically, endogenous relaxin treatment reduces myogenic reactivity through nitric oxide (NO)-mediated vasorelaxation and increases arterial compliance in small resistance arteries. However, less is known about the vascular roles of endogenous relaxin, particularly in males. Therefore, we used male wild-type (Rln+/+) an...

OBJECTIVE The vasa vasorum form a network of microvessels in and around the walls of large blood vessels and are thought to be necessary to delivery oxygenated blood to the outer parts of the vessel wall that are inadequately nourished by diffusion from luminal blood. This study was undertaken to investigate directly the mechanisms which control tone in the vasa vasorum. METHODS Arterial vasa...

Ethanol has been reported to cause hypertension, the mechanism of which is unknown. Therefore, the effect of chronic ethanol consumption on vascular responsiveness and blood pressure was investigated. Systolic blood pressure was recorded weekly by tail-cuff method. Aortic rings from rats fed chow ad libitum or pair-fed liquid diets containing either ethanol (7.2% v/v) or isocaloric carbohydrate...

The potent vasoconstrictor endothelin leads to smooth muscle cell depolarization and increases in intracellular Ca2+. Although effects of endothelin on calcium channels have been described, it also has been speculated that endothelim may activate additional ion channels. The purpose of the present study was to identify an alternative ion current that could play a role in depolarizing cells in r...

Prolonged untreated diabetes mellitus leads to microangiopathy, tissue hypoxia and ischemic lesions; it increases the risk for stroke and exacerbates brain tissue damage following ischemia. Patients exhibit advanced atherosclerosis in coronary and cerebral arteries as well as enhanced vascular responsiveness to vasoconstrictors, an attenuated response to vasodilators and impaired autoregulation...

Prostanoids derived from arachidonic acid (AA) have been shown to play a permissive role in the regulation of vascular tone and wall tension. Conventionally, epoxyeicosatrienoic acids (EETs) and prostacyclin have been considered as dilatators, whereas thromboxane (TX) and hydroxyeicosatetraenoic acid (HETE) were considered as vasoconstrictors. However, the role of these prostanoids in the media...

INTRODUCTION The mechanism by which blood transfusion increases blood pressure in a substantial proportion of patients with congenital hemolytic anemia is unknown. Vascular endothelium dysfunction and increased endogenous vasoactive substances have been postulated in the pathogenesis of hypertension following multiple blood transfusions. The present study was undertaken to test the hypothesis w...