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Diabetes mellitus is known to produce alterations in vascular reactivity. In the present study we have examined the effects of short-term diabetes on histamine-induced relaxation of isolated mesenteric arteries, and the role of the endothelial cell layer in this response. Removal of the endothelium completely abolished the histamine relaxation effect in(More)
Nitric oxide (NO) released from endothelial cells or exogenous nitrates is a potent dilator of arterial smooth muscle; however, the molecular mechanisms mediating relaxation to NO in the microcirculation have not been characterized. The present study investigated the relaxant effect of nitrovasodilators on microvessels obtained from the rat mesentery and(More)
The ability of nifedipine to inhibit contractions induced by non-selective and selective alpha adrenoceptor agonists and by KCl depolarization was studied in the rat aorta. The presence of alpha-2 adrenoceptors which mediate vasoconstriction was demonstrated. Furthermore, this response was highly dependent on extracellular calcium. Alpha-1 adrenoceptors(More)
Hypertension, atherosclerosis, arteriosclerosis, and cardiomyopathy account for 80% of all diabetic deaths. A paucity of data exists concerning reactivity of the diabetic vasculature to vasopressor substances. The purpose of this investigation was to determine the influence of short-term (4-5 weeks) diabetes on the responsiveness of the cardiovascular(More)
cAMP-dependent vasodilators are used to treat a variety of cardiovascular disorders; however, the signal transduction pathways and effector mechanisms stimulated by these agents are not fully understood. In the present study we demonstrate that cAMP-stimulating agents enhance the activity of the large-conductance, calcium-activated potassium (BK(Ca))(More)
OBJECTIVE Postmenopausal estrogen replacement therapy lowers the incidence of cardiovascular disease, suggesting that estrogens support cardiovascular function. Estrogens dilate coronary arteries; however, little is known about the molecular basis of how estrogen affects the human coronary circulation. The cellular/molecular effects of estrogen action on(More)
Autonomic neuropathy is a major complication of chronic diabetes and is responsible for disturbances in the cardiovascular system and other organs. Early cardiac disturbances have been attributed to defective vagal control of the heart. The heart rates of rats with chemically-induced diabetes are depressed and an increase in blood pressure produces a(More)
The present investigation was undertaken to determine the action of dimethyl sulfoxide (Me2SO) on vascular smooth muscle. The rabbit isolated aortic strip preparation was used. In the present study, Me2SO-induced relaxation of isolated rabbit aorta was demonstrated. The degree of relaxation induced by Me2SO was concentration dependent. In the presence of(More)
It is well known that the vascular endothelial cell layer plays an essential role in the vasodilatory response of several agents. In this study we have investigated the possibility that the endothelium may also modulate alpha adrenergic agonist-induced vasoconstriction. The responses of rat aortae to selective alpha-1 and alpha-2 adrenergic agonists were(More)
Previous results from our laboratory (White and Carrier, Enhanced Vascular Alpha-Adrenergic Neuroeffector System in Diabetes: Importance of Calcium. Am. J. Physiol. 255: H1036-1042, 1988) demonstrated that mesenteric arteries from streptozotocin (STZ)-diabetic rats exhibit an enhanced responsiveness to alpha adrenergic agonists. The present study(More)