Local heating of the skin is commonly used to assess cutaneous microvasculature function. Controversy exists as to whether there are limb or sex differences in the nitric oxide (NO)-dependent contribution to this vasodilation, as well as the NO synthase (NOS) isoform mediating the responses. We tested the hypotheses that 1) NO-dependent vasodilation would be greater in the calf compared with th...

This study aimed to investigate the relationship between oxidative stress and endothelium-dependent vasodilation in patients with chronic renal failure (CRF). Thirty-seven patients with CRF underwent evaluation of endothelium-dependent vasodilation and endothelium-independent vasodilation by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arteri...

BACKGROUND Endothelium-dependent vasodilation in response to acetylcholine (ACh) and ischemic vasodilation during reactive hyperemia are attenuated in the forearm of patients with heart failure (HF). It has been shown that L-arginine augments endothelium-dependent vasodilation in healthy subjects. Thus, the aim of the present study was to determine if L-arginine improves endothelium-dependent a...

This study determined the role of nitric oxide (NO) in neurogenic vasodilation in mesenteric resistance arteries of the toad, Bufo marinus. Nitric oxide synthase (NOS) was anatomically demonstrated only in perivascular nerves but not the endothelium. Acetylcholine (ACh) and nicotine caused tetrodotoxin (TTX)-sensitive neurogenic vasodilation of mesenteric arteries. The ACh-induced vasodilation ...

Although very common, the precise mechanisms that explain symptomatology of neuroendocrine syncope (NES) remain poorly understood. This disease, which can be incapacitating, manifests itself as a drop in blood pressure secondary to vasodilation and/or extreme slowing heart rate. As studies continue, involvement adenosinergic system is becoming increasingly evident. Adenosine, an ATP derivative,...

Impairment of flow-induced vasodilation in coronary resistance arterioles may contribute to the decline in coronary vasodilatory reserve that occurs with advancing age. This study investigated the effects of age on flow-induced signaling and activation of nitric oxide (NO)-mediated vasodilation in coronary resistance arterioles. Coronary arterioles were isolated from young (approximately 6 mo) ...

Chronic cytomegalovirus (CMV) infections are implicated in vascular diseases. Recently, we showed that an active mouse CMV (mCMV) infection in nonpregnant mice increased endothelial-dependent vasodilation in isolated mesenteric and uterine arteries. In late pregnancy, while increased vasodilation was found in mesenteric arteries from infected mice, there was a dramatic decrease in uterine arter...

The purpose of this study was to determine whether activation of prostaglandin H(2)-thromboxane A(2) (PGH(2)-TxA(2)) receptors impedes vasodilation in the in situ peripheral microcirculation of spontaneously hypertensive hamsters, a new rodent model of high-renin genetic hypertension. Using intravital microscopy, we found that vasodilation elicited by suffusion of acetylcholine and vasoactive i...

The role of P1 receptors and P2Y1 receptors in coronary vasodilator responses to adenine nucleotides was examined in the isolated guinea pig heart. Bolus arterial injections of nucleotides were made in hearts perfused at constant pressure. Peak increase in flow was measured before and after addition of purinoceptor antagonists. Both the P1 receptor antagonist 8-(p-sulfophenyl)theophylline and a...

BACKGROUND Chronic coronary occlusion (CCO) impairs endothelial function of distal collateral-dependent microvasculature; however, long-term exercise training (EX) seems to improve endothelial dysfunction. We hypothesized that EX enhances vasodilation responses to vascular endothelial growth factor (VEGF165), mediated via nitric oxide (NO), in arterioles exposed to CCO. METHODS AND RESULTS Th...