Search results for "Vasoconstriction"
showing 10 items of 134 documents
Administration of transforming growth factor-α reduces infarct volume after transient focal cerebral ischemia in the rat
2001
Growth factors promote cell growth and survival and protect the brain from developing injury after ischemia. In this article, the authors examined whether transforming growth factor-α (TGF-α was protective in transient focal ischemia and whether alteration of cerebral circulation was involved. Rats received intraventricular TGF-α (50 ng, either split into 2 doses given 30 minutes before and 30 minutes after middle cerebral artery occlusion (MCAO), or 1 dose given 30 minutes after MCAO) or vehicle. Rats were subjected to 1-hour intraluminal MCAO and cerebral blood flow was recorded continuously by laser-Doppler flowmetry. Infarct volume was measured 1 and 4 days later. The effects of TGF-α o…
Endothelin-1-induced potentiation of adrenergic responses in the rabbit pulmonary artery: role of thromboxane A(2).
2001
Abstract To examine whether low concentrations of endothelin-1 potentiate the vasocontrictor response to adrenergic stimulation, we recorded the isometric response of rings of rabbit pulmonary artery to electrical stimulation and noradrenaline. Endothelin-1 (10 −10 M) potentiated the contractions induced by electrical stimulation and noradrenaline. The endothelin ET B receptor antagonist (2,6-dimethylpiperidinecarbonyl-γ-methyl-Leu- N in -[Methoxycarbonyl]- d -Trp- d -Nle) (BQ-788, 10 −6 M), but not the endothelin ET A receptor antagonist cyclo( d -Asp-Pro- d -Val-Leu- d -TRP) (BQ-123, 10 −6 M), inhibited the potentiating effects of endothelin-1. Pretreatment with the cyclooxygenase inhibit…
Experimental diabetes induces hyperreactivity of rabbit renal artery to 5-hydroxytryptamine.
2002
Abstract The influence of diabetes on the response of isolated rabbit renal arteries to 5-hydroxytryptamine (5-HT) was examined. 5-HT induced a concentration-related contraction that was higher in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal did not significantly modify 5-HT contractions in arteries from control rabbits but enhanced the response to 5-HT in arteries from diabetic rabbits. Incubation with N G -nitro- l -arginine ( l -NA) enhanced contractions to 5-HT in arteries from control and diabetic rabbits. In arteries with endothelium, this l -NA enhancement was lower in diabetic rabbits than in control rabbits. In arteries without endotheli…
Effects of a nitrate-free interval on tolerance, vasoconstrictor sensitivity and vascular superoxide production
2000
Abstract 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 in patients with stable coronary arteries, suggesting a rebound-like situation during the patch-off period. Recently, we demonstrated that long-term treatment with NTG induces tolerance, which was in part related to increases in vascular O2•− and increased vasoconstrictor sensitivity. METHODS …
Pharmacological profile of phytoestrogens in cerebral vessels: in vitro study with rabbit basilar artery.
2003
As a previous step to consider their use in the pharmacology for stroke, we investigated the effects of four phytoestrogens (i.e. genistein, daidzein, zearalanone and biochanin A) on cerebral vessels. Cerebral vascular responses were analyzed by conventional recording of isometric tension in rabbit basilar artery segments kept in organ bath under standard conditions. The four phytoestrogens elicited concentration-dependent relaxant responses of different potency in basilar artery segments previously contracted with either 5x10(-2) M KCl or 10(-4) M UTP. Neither endothelium removal, 10(-4) M N(omega)-nitro-L-arginine methyl ester (L-NAME, nitric oxide (NO) synthase inhibitor), 10(-5) M1 H-[1…
Increased responsiveness of human pulmonary arteries in patients with positive bronchodilator response.
1996
Abstract 1. The effects of noradrenaline, endothelin-1, acetylcholine and sodium nitroprusside were studied in isolated pulmonary arteries obtained from 14 patients undergoing lobectomy for lung carcinoma. Seven patients had shown increased response to a bronchodilator test prior to operation. In the remaining patients (control) the bronchodilator test was negative. 2. Artery rings from patients with a positive bronchodilator response showed greater contraction to noradrenaline (pD2 = 6.44 +/- 0.1; Emax = 93 +/- 9% of response to 100 mM KCl) and endothelin-1 (pD2 = 8.92 +/- 0.1; Emax = 130 +/- 16%) than the rings from control patients (pD2 = 6.04 +/- 0.08; Emax = 56 +/- 8% for noradrenaline…
Antihypertensive effects of lactoferrin hydrolyzates: Inhibition of angiotensin- and endothelin-converting enzymes
2013
The potential of bovine lactoferrin (LF) as a source of antihypertensive peptides acting on the renin-angiotensin system (RAS) and the endothelin (ET) system as dual vasopeptidase inhibitors has been examined. For this purpose enzymatic LF hydrolyzates (LFHs) were generated by trypsin and proteinase K digestions. Permeate fractions with molecular masses lower than 3 kDa (LFH <3 kDa) were orally administered to spontaneously hypertensive rats (SHRs). Although both LFHs <3 kDa showed in vitro angiotensin I-converting enzyme (ACE)-inhibitory activity, only proteinase K LFH <3 kDa exerted an in vivo antihypertensive effect. The proteinase K LFH <3 kDa and a previously characterized pepsin LFH <…
Effects of Ca2+ entry blockers on CaCl2-, KCl- and noradrenaline-induced contractions of goat cerebral arteries
1990
Abstract The effects of three Ca 2+ entry blockers, nicardipine, nimodipine and verapamil, on CaCl 2 -, KCl- and noradrenaline-induced contractions were examined in isolated goat middle cerebral artery. The relationship between the effects of Ca 2+ entry blockers and the extracellular Ca 2+ dependence of the contractions was also examined. In ‘nominally’ Ca 2+ -free medium, addition of CaCl 2 induced concentration-dependent contractions of previously depolarized arteries. Withdrawal of Ca 2+ from the extracellular medium caused strong inhibition of the KCl- and noradrenaline-induced arterial contractions. Addition of EGTA to the Ca 2+ -free medium almost abolished the noradrenaline-response…
Aging-related endothelial dysfunction in the aorta from female senescence-accelerated mice is associated with decreased nitric oxide synthase express…
2013
The present study investigated the time-course for aging-associated effects on contractile and relaxing vascular responses and nitric oxide (NO) production in the aorta from female senescence-accelerated resistant (SAMR1) and prone (SAMP8) mice. Both SAMR1 and SAMP8 were studied at three different ages: 3 (young), 6 (middle age) and 10 (old) months. Concentration-response curves to phenylephrine (10(-8) to 10(-5) M) or acetylcholine (10(-9) to 10(-5) M) were performed in the aortic rings in the absence or in the presence of NO synthase (NOS) inhibitor L-NAME (10(-4) M). Protein and gene expression for endothelial NOS (eNOS) was determined by immunofluorescence, Western blot and real-time PC…
Isolated Lung Perfusion as an Adjuvant Treatment of Colorectal Cancer Lung Metastases: A Preclinical Study in a Pig Model
2012
BackgroundThe lung is a frequent site of colorectal cancer (CRC) metastases. After surgical resection, lung metastases recurrences have been related to the presence of micrometastases, potentially accessible to a high dose chemotherapy administered via adjuvant isolated lung perfusion (ILP). We sought to determine in vitro the most efficient drug when administered to CRC cell lines during a short exposure and in vivo its immediate and delayed tolerance when administered via ILP.MethodsFirst, efficacy of various cytotoxic molecules against a panel of human CRC cell lines was tested in vitro using cytotoxic assay after a 30-minute exposure. Then, early (operative) and delayed (1 month) tolera…