This study examined why an artery becomes vulnerable to spasm when used as a bypass graft. We hypothesized that high flow demands would decrease pressure distally in the conduit (afterload), thus increasing the sensitivity to vasoconstrictors. Furthermore, perioperative endothelial dysfunction would additionally sensitize the artery to constrictors. Six gastroepiploic arteries (GEA, 1.0-1.5 mm ...

Triptans are agonists at 5-HT1B and 5-HT1D (where 5-HT is 5-hydroxytryptamine; serotonin) receptors and cause vasoconstriction of isolated blood vessels. The aim of the present study was to determine vasoconstrictor potency (EC50) of triptans in human coronary and cerebral arteries and to examine whether there was any relationship with the maximal plasma concentrations (Cmax; nM) of the drugs a...

Overproduction of nitric oxide and activation of soluble guanylate cyclase (sGC) are important in sepsis-induced hypotension and hyporesponsiveness to vasoconstrictors. A time course of the expression and activity of sGC in a sepsis model [cecal ligation and puncture (CLP)] was evaluated in rats. Soluble GC alpha-1 and beta-1 subunit mRNA levels increased in the lungs, but not in the aorta. How...

Introduction: Patients with heart diseaseoften do not get adequate surgical interventions because doctors fear the complications that may develop after the use of vasoconstrictors in local anesthetics. The purposeof the study is to determine the kind ofinfluence that Adrenalin has in the local anesthetic Unistesin in outpatient service of surgical patients that suffer from controlled forms of h...

OBJECTIVES In the present study, we tested whether a nitrate-free interval is able to prevent increases in vascular superoxide (O2*-) and the development of hypersensitivity to vasoconstrictors and whether this may result in restoration of vascular nitroglycerin (NTG) sensitivity. BACKGROUND Intermittent NTG-patch treatment (12 h patch on/patch-off) has been shown to increase ischemic periods...

Some otolaryngologists administer topical phenylephrine for bleeding control in adenoidectomy surgery. Absorption of this drug from surgical site can lead to increase in blood pressure due to vasoconstriction and then bradycardia related to baroreceptore reflex.  Our case was an intraoperative arrest of a 9-yrs-old girl related to administration of topical phenylephrine during adenoidectomy how...

The injection of vasoconstrictors together with a local anaesthetic will prolong the duration of spinal anaesthesia. We use phenylephrine ((-)-l-(mhydroxyphenyl>2-methyl-aminoethanol HQ), which has been reported to double the duration of anaesthesia (Moore and Bridenbaugh, 1966). These authors found no systemic response to the added phenylephrine in a retrospective study of 1911 spinal anaesthe...

Spectral analysis of cardiovascular signals has been extensively used to investigate circulatory homeostatic mechanisms. However, the nature of very low-frequency (VLF) fluctuations remains unclear. Because we previously observed enhanced VLF fluctuations in blood pressure (BP) in the sympathectomized rat (a model characterized by markedly increased plasma epinephrine levels), the aims of our s...

Recently, hypertrophy and increased myogenic tone of brain vessels have been observed in rats after simulated microgravity. It is expected that simulated microgravity may also induce hyperreactivity of brain vessels. To test this hypothesis, Sprague-Dawley rats were subjected to a 4-wk tail-suspended hindlimb unloading (TS) to simulate the cardiovascular deconditioning effect of microgravity. A...