Ralph E Purdy

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The effects of carbamazepine, in vitro, on adrenergic neuronal and whole brain synaptosomal uptake and release of tritiated norepinephrine (3H-NE) were assessed. At 10(-4) M, carbamazepine inhibited 3H-NE uptake by 22% in rabbit thoracic aorta and in brain synaptosomes. At the same concentration, carbamazepine inhibited stimulation-induced release of 3H-NE(More)
The literature provides evidence for non-uniform regional changes in cerebral blood flow under a variety of circumstances. Possible causes of such changes were sought in the larger cerebral arteries of the rabbit prepared according to the glyoxylic acid fluorescence histochemical technique. The adrenergic innervation of the circle of Willis, the basilar(More)
The aim of the present work was to investigate the alterations in nitric oxide synthase (NOS) expression and nitrate and nitrite (NOx) content of different arteries from simulated microgravity rats. Male Wistar rats were randomly assigned to either a control group or simulated microgravity group. For simulating microgravity, animals were subjected to(More)
Simulated microgravity depresses the ability of arteries to constrict to norepinephrine (NE). In the present study the role of nitric oxide-dependent mechanisms on the vascular hyporesponsiveness to NE was investigated in peripheral arteries of the rat after 20 days of hindlimb unweighting (HU). Blood vessels from control rats and rats subjected to HU (HU(More)
The goal of this study was to determine the effects of microgravity on myofilament protein expression and both passive and active length-force relationships in carotid and femoral arteries. Microgravity was simulated by 20-day hindlimb unweighting (HU) in Wistar male rats, and carotid and femoral artery segments were isolated from both HU and control (CTL)(More)
Vessel dimensions and characteristic responses to norepinephrine were measured in various arteries and veins of the rabbit made hypertensive by partial constriction of the upper abdominal aorta. The ear, radial, and basilar arteries taken from the circulation proximal to the ligature (the hypertensive arteries) were thickened in proportion to the rise is(More)
Angiotensin II (Ang II) is known to enhance the vasoconstrictor response to norepinephrine (NE). In the present study, this interaction was investigated using isolated rabbit femoral artery rings mounted in tissue baths for the measurement of isometric contraction. Exposure to 3 x 10(-10) M Ang II caused a contraction that was less than 5% of the maximal(More)
Isolated rings of rabbit thoracic aorta were mounted in tissue baths for the measurement of isometric contraction, and the effects of combinations of two agonists were studied. Concentrations of methoxamine, clonidine, norepinephrine (NE), 5-hydroxytryptamine (5-HT) and potassium causing threshold contraction (0.1 g) were determined. Combinations of any two(More)
The possibility of changes in the adrenergic innervation of blood vessels in experimental hypertension was investigated by measuring arterial norepinephrine content, neuronal uptake of norepinephrine, and the neurogenic contractile response in rabbits made hypertensive by partial constriction of the abdominal aorta proximal to the kidneys. Two to 3 weeks(More)
BACKGROUND Chronic renal insufficiency (CRI) is associated with a high incidence of hypertension (HTN), endothelial dysfunction, atherosclerosis and cardiovascular disease. Sedentary life style increases, whereas regular exercise reduces the risk of cardiovascular disease. This study was designed to test the effect of regular exercise on vasodilatory and(More)