Search results for "Ephrin"
showing 10 items of 345 documents
0110 : Experimental cerebral ischemia in rats increases myocardial vulnerability to ischemia-reperfusion injury ex vivo
2016
For years, the relationship between cardiac and neurological ischemic events has been mainly attributed to overlapping pathophysiological mechanisms and common risk factors. However, acute stroke may induce dramatic alterations of cardiovascular function. The aim of this work was to evaluate how prior cerebrovascular lesions affect myocardial function in vivo and ex vivo , as well as myocardial vulnerability to ischemic injury. Cerebral embolization was performed in adult Wistar male rats by the injection of microspheres into the left internal carotid artery. Left ventricular function, investigated in vivo using echocardiography (1 hour, 24 hours and 7 days after the embolization), was not …
Modulation by docosahexaenoic acid of the epinephrine-stimulated adenylate cyclase activity of the bovine retina.
1988
This work shows that unsaturated fatty acids enhance the epinephrine-stimulated adenylate cyclase activity in bovine retina. The modulating effect on the epinephrine-stimulated formation of cyclic AMP seems to be linked to the degree of unsaturation of the fatty acid. Treatment of the intact retina with docosahexaenoic acid in the concentration range 0.5 X 10(-6)-1 X 10(-3) M does not affect the enzyme activity measured in the absence of the hormone but markedly increases the cyclase activity when the tissue is incubated in the presence of 0.1 mM epinephrine. Docosahexaenoic acid enhances the maximal response to epinephrine without affecting the apparent ED50 value for this effector. Docosa…
Stimulation of calcium uptake by norepinephrine or high external potassium in human calyces and renal pelvis.
1989
The effects of stimulation with either 10 mumol/l norepinephrine or 85 mmol/l extracellular potassium concentration on calcium uptake were studied in muscle strips from human renal calyces and from the renal pelvis. The apparent uptake of calcium under control conditions was essentially complete after 30 min. Stimulation of the muscle strips with norepinephrine or high external potassium significantly (P less than 0.05) increased the calcium uptake over the control values at 30 and 100 min, whereas 45Ca efflux was virtually not affected. It is concluded that the mechanical responses of the muscle strips to norepinephrine or high external potassium correspond with an increased uptake of calc…
Stress hormones promote growth of B16-F10 melanoma metastases: an interleukin 6- and glutathione-dependent mechanism
2013
[EN] Background: Interleukin (IL)-6 (mainly of tumor origin) activates glutathione (GSH) release from hepatocytes and its interorgan transport to B16-F10 melanoma metastatic foci. We studied if this capacity to overproduce IL-6 is regulated by cancer cell-independent mechanisms. Methods: Murine B16-F10 melanoma cells were cultured, transfected with red fluorescent protein, injected i.v. into syngenic C57BL/6J mice to generate lung and liver metastases, and isolated from metastatic foci using high-performance cell sorting. Stress hormones and IL-6 levels were measured by ELISA, and CRH expression in the brain by in situ hybridization. DNA binding activity of NF-kappa B, CREB, AP-1, and NF-IL…
Vasoactive intestinal peptide stimulation of cyclic guanosine monophosphate formation: further evidence for a role of nitric oxide synthase and cytos…
1993
In the rat pineal gland vasoactive intestinal peptide (VIP) and beta-adrenergic agonists stimulate cyclic guanosine monophosphate (cGMP) formation and their action is amplified by alpha 1-adrenergic agonists. Since beta-adrenergic stimulation of cGMP is suggested to involve activation of nitric oxide (NO) synthase and NO-mediated activation of cytosolic guanylate cyclase (GC), we investigated the effects of the NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA) and of the cytosolic GC inhibitor methylene blue (MB) on VIP receptor-stimulated cGMP formation. Both L-NMMA and MB depressed VIP-induced cGMP formation as well as alpha 1-adrenergic potentiation of VIP-stimulated cGMP formation …
Vascular effects of progesterone: Role of cellular calcium regulation
2001
Abstract —Vascular actions of progesterone have been reported, independently of estrogen, affecting both blood pressure and other aspects of the cardiovascular system. To study possible mechanisms underlying these effects, we examined the effects of P in vivo in intact rats and in vitro in isolated artery and vascular smooth muscle cell preparations. In anesthetized Sprague-Dawley rats , bolus intravenous injections of P (100 μg/kg) significantly decreased pressor responses to norepinephrine (0.3 μg/kg). In vitro, progesterone (10 −8 to 10 −5 mmol/L) produced a significant, dose-dependent relaxation of isolated helical strips, both of rat tail artery precontracted with KCl (60 mmol/L) or a…
Platelet Activity in Relation to Smoke and Exercise in Patients with Chronic Obstructive Lung Disease: Effects of Platelet Antiaggregating Drugs
1984
Lung tissue is involved in the synthesis and/or metabolism of many vasoactive substances such as histamine, serotonin, dopamine, norepinephrine, bradikinin, angiotensin II and prostaglandins (1).
Resistance exercise-induced hormonal response under the influence of delayed onset muscle soreness in men and boys
2010
It was hypothesized that exercise-induced muscle damage (EIMD)-related alterations in hormonal responses could be observed if a second exercise bout is performed soon after an identical unaccustomed bout leading to delayed onset muscle soreness (DOMS). Eight men (31 ± 7 years) and eight boys (14 ± 0 years) performed two exercise bouts (E1 and E2, with 48 h rest in between) consisting of three sets of bilateral knee extensions until exhaustion with 40% load. No differences between the groups or bouts were observed in the number of repetitions performed and maximal isometric force decline, or between groups in serum creatine kinase activity and DOMS. Decreased peak epinephrine (EPI) (-38%), g…
Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine
1998
Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine. Myogenic, pressure-induced vasoconstriction may amplify the effects of circulating vasoconstrictors. Through intravital microscopy in cremaster arterioles (31 to 115 μm diameter), the relative contribution of myogenic responses (MR) to norepinephrine (NE)-induced constriction and the inhibitor potency of nitric oxide (NO) or a Ca2+ entry blocker (CEB), felodipine (F), were examined. In 24 anesthetized hamsters, a vessel occluder was placed around the aorta to control cremaster vessel inflow pressure (IP). NE infusion increased blood pressure (by 50 ± 2mm Hg) and induced significant constriction …
Effect of Phenylephrine on the Accommodative System
2016
Accommodation is controlled by the action of the ciliary muscle and mediated primarily by parasympathetic input through postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia. During accommodation the pupil constricts to increase the depth of focus of the eye and improve retinal image quality. Researchers have traditionally faced the challenge of measuring the accommodative properties of the eye through a small pupil and thus have relied on pharmacological agents to dilate the pupil. Achieving pupil dilation (mydriasis) without affecting the accommodative ability of the eye (cycloplegia) could be useful in many clinical and research contexts. Phenylephr…