Exposure of isolated arteries to oxidatively modified low density lipoprotein (LDL) has been reported to suppress endothelium-dependent relaxation (EDR). To determine whether lipid degradation products in oxidized LDL contribute to impaired relaxation, we have tested the responsiveness of isolated rabbit aortas to endothelium-dependent relaxants (acetylcholine, ATP, and calcium ionophore A23187...

Beta-adrenergic receptor (βAR)-dependent blood vessel relaxation is impaired in older animals and G protein activation has been suggested as the causative mechanism. Here, we investigated the role of βAR subtypes (β1AR, β2AR, and β3AR) and cAMP in maturation-dependent vasorelaxation impairment. Aortic rings from 15 Sprague-Dawley male rats (3 or 9 weeks old) were harvested and left intact or de...

We investigated endothelium-dependent relaxation in rat aortae, using three models of experimental hypertension: deoxycorticosterone and salt; one-kidney, one clip renovascular hypertension; and coarctation. Isolated aortae were contracted with phenylephrine, and relaxation was subsequently induced with acetylcholine or calcium ionophore A23187. Blood vessels denuded of endothelium did not rela...

PURPOSE Carbon monoxide (CO) may mediate smooth muscle relaxation in the rat corpus cavernosum smooth muscle (CCSM). We hypothesized that CO plays a role in neurally derived, frequency-dependent relaxation of rat CCSM. MATERIALS AND METHODS To study the effect of CO on CCSM relaxation induced by electrical field stimulation (EFS), a CCSM bundle was mounted on a force transducer and perfused w...

Leukotriene D4 has been shown to possess the capacity to relax canine superior mesenteric and renal arterial rings in an endothelial-dependent manner. The present study was designed to determine if the remaining peptidoleukotrienes, leukotrienes C4 and E4, share this property. In addition, influences of atropine and of inhibitors of cyclooxygenase and lipoxygenase activities on relaxation produ...

It has been previously shown that vasoactive intestinal polypeptide (VIP) induces endothelium-dependent relaxation of the human uterine artery. However, the nature of the mediator of the VIP-induced endothelium-dependent relaxation of the human uterine artery has not yet been determined. Therefore these experiments were undertaken to examine the effects of VIP on human uterine arteries and to e...

Previously, we showed that development of myocardial necrotic lesions is associated with impaired endothelium-dependent coronary artery relaxation in young cardiomyopathic hamsters. Since active necrosis declines with aging, this study was designed to determine whether coronary artery endothelium-dependent relaxation to ACh is restored and to identify the mechanisms mediating this effect. Intra...

We studied the effects of acetylcholine and calcium ionophore A23187 on human basilar artery rings. Among 11 arteries, both agents produced significant relaxations in five, A23187 but not acetylcholine caused a response in six, and neither agent was effective in four. After rubbing off the endothelium, the relaxations induced by both agents were significantly attenuated. Indomethacin (a cycloox...

BACKGROUND Thiopental induces relaxation of vascular smooth muscle cells through its direct and/or indirect vasodilator effects. The perivascular adipose tissue (PVAT) and the endothelium are known to attenuate vascular contraction, and we have recently reported that PVAT potentiates the relaxation effect of propofol through endothelium-dependent and -independent mechanisms. Here, we studied th...