Search Results
Results 201 - 250 of 1010
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Kaplan Steven A - - 2006
The prevalence of benign prostatic hypertrophy (BPH) and erectile dysfunction (ED) both increase with age, and increasing evidence suggests a common cause rather than independent age-related changes. Arterial hypertension often accompanies these urological disorders, suggesting the possibility that increased alpha-adrenoceptor activity may be causal in all three conditions. As evidence ...
Sy Guata Yoro - - 2006
This work aimed to study the respective effects of central alpha2-adrenergic receptors (alpha2-ARS) and I1 imidazoline receptors (I1Rs) in the facilitatory effects of imidazoline-like drugs on the reflex bradycardia (RB). Experiments were performed in anaesthetized rabbits. The reflex bradycardic response was induced by phenylephrine injected i.v. LNP 509, rilmenidine and ...
Le Mével Jean-Claude - - 2006
In this review, we summarize the most significant data concerning the cardiovascular effects of centrally and peripherally administered synthetic trout corticotropin-releasing factor (CRF) and urotensin-I (U-I) in our animal model, the unanesthetized trout Oncorhynchus mykiss. Although there is more than 60% sequence identity between these two stress-related neurohormonal peptides, CRF ...
Shibao Cyndya - - 2006
Patients with autonomic failure are disabled by orthostatic hypotension, which can be worsened by the nighttime pressure natriuresis induced by associated supine hypertension. Several pharmacological agents are available that effectively reduce nighttime hypertension, but none of them prevent pressure natriuresis. Because hypertension of autonomic failure can be driven by residual ...
Kaczyñska Katarzyna - - 2006
The respiratory effects of stimulation of alpha2-adrenergic receptors were studied in spontaneously breathing anaesthetized rats that were neurally intact, or bilaterally vagotomized, or subjected to bilateral combined midcervical vagotomy and section of the carotid sinus nerves. An intravenous clonidine bolus (15 microg kg(-1)) evoked a prolonged slowing of the respiratory ...
Vagts D A - - 2005
BACKGROUND AND OBJECTIVE: Clonidine, which is used for induction of sympatholysis and prevention or treatment of alcohol withdrawal in anaesthesia and intensive care medicine, may have deleterious effects on intestinal mucosal perfusion. This study was designed to investigate the effects of clonidine on intestinal perfusion and oxygenation. METHODS: Following ethical ...
Shiratsuch Hiroe - - 2005
BACKGROUND: Cytokine production by macrophages is essential for the inflammatory response. Normal human interstitial tissue pressure is 20 to 30 mm Hg, but generally decreases in acute inflammation. METHODS: We compared the effect of 20 mm Hg increased pressure (approximating normal interstitial tissue pressure) with that of ambient pressure (resembling ...
Hou R H - - 2005
RATIONALE: Modafinil is a wakefulness-promoting drug which is likely to activate some wakefulness-promoting and/or inhibit sleep-promoting neurones in the brain. The locus coeruleus (LC) is a wakefulness-promoting noradrenergic nucleus whose activity can be "switched off" by the alpha2-adrenoceptor agonist clonidine, leading to sedative and sympatholytic effects. OBJECTIVE: The aim of ...
Li Guichu - - 2005
We tested the hypothesis that the I1 receptor mediates the reduction in rostral ventrolateral medulla (RVLM) neuronal norepinephrine (NE; index of sympathetic activity) that leads to hypotension independent of other brainstem areas or the alpha2-adrenergic receptor. To this end, we developed a model that permitted measurement of real-time changes in ...
Jacob Giris - - 2005
We reported previously that intravenous administration of tyramine induced a paradoxical forearm vasodilation and an increase in plasma dopamine, raising the possibility that dopamine is released by or converted from tyramine in vivo. Alternatively, tyramine can be nonenzymatically oxidized into dopamine in vitro, and this contamination may be responsible for ...
Brkovic B - - 2005
The admixture of clonidine or epinephrine to lidocaine for inferior alveolar nerve block was studied with regard to onset, duration, intensity of anaesthesia, postoperative analgesia, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), ST segment depression > or =1 mm and cardiac arrhythmias. ...
Adnan T - - 2005
BACKGROUND: Clonidine is often used as an adjuvant for local anaesthetics in regional anaesthesia; however, its effects on axillary block in chronic renal failure patients have not been investigated. These effects were the focus of this study. METHODS: Twenty-eight adult chronic renal failure patients (ASA physical status III) scheduled for ...
Kaye Alan D - - 2005
Availability of opiate substances through physicians and on the street has led to a rise in dependence and in addiction resulting in countless numbers of people hooked on these drugs. Long-term use of these agents results in reduction of endogenous supply of opiate replaced by these exogenous compounds. A technique ...
Mizobe T - - 2005
Perioperative hypothermia is common and results from anaesthesia-induced inhibition of thermoregulatory control. Hypothermia is blunted by baroreceptor unloading caused by positive end-expiratory pressure (PEEP), and is mediated by an increase in the vasoconstriction threshold. Premedication with clonidine impairs normal thermoregulatory control. We therefore determined the effect of clonidine on PEEP-induced ...
Cabrales Pedro - - 2005
A surface-modified polyethylene glycol-conjugated human hemoglobin (MP4) and alpha alpha-cross-linked human hemoglobin (alpha alpha Hb) were used to restore oxygen carrying capacity in conditions of extreme hemodilution (hematocrit 11%) in the hamster window model preparation. Changes in microvascular function were analyzed in terms of effects on capillary pressure and functional ...
Mitchell Anna - - 2005
PURPOSE: Clonidine is a classical sympatholytic drug that is widely used for the treatment of hypertension. Experimental and clinical studies suggest that Clonidine may activate baroreflex. The aim of this study was to determine the hemodynamic response to Clonidine under physiological conditions and to test the hypothesis that Clonidine would ...
Jacob A M - - 2005
The goal of this study is to assess the local mechanical environment of the pulmonary epithelium in a computational model of airway reopening. To this end, the boundary element method (BEM) in conjunction with lubrication theory is implemented to assess the stationary-state behavior of a semi-infinite bubble traveling through a ...
Estato V - - 2004
We investigated the acute effects of centrally acting antihypertensive drugs on the microcirculation of pentobarbital-anesthetized spontaneously hypertensive rats (SHR). The effects of the sympatho-inhibitory agents clonidine and rilmenidine, known to activate both alpha2-adrenoceptors and nonadrenergic I1-imidazoline binding sites (I1BS) in the central nervous system, were compared to those of dicyclopropylmethyl-(4,5-dimethyl-4,5-dihydro-3H-pyrrol-2-yl)-amine ...
Ohtake Akiyoshi - - 2004
The aim of the present study was to investigate the effects of tamsulosin, an alpha(1)-adrenoceptor antagonist, on hypogastric nerve stimulation-induced intraurethral pressure elevation in anesthetized male and female dogs and to evaluate sex differences in these effects. Additionally, the effects of tamsulosin were also compared with those of other alpha(1)-adrenoceptor ...
de Padua Adriana Inacio - - 2004
Several drugs have been employed for sedation during flexible fiberoptic bronchoscopy (FOB). Clonidine attenuates stress-induced sympathoadrenal responses and has sedative properties. We investigate the effects of clonidine premedication on hemodynamic and comfort parameters of patients submitted to FOB under airway topical anesthesia only. Patients received placebo (n = 22; men ...
Missant Carlo - - 2004
PURPOSE: Intrathecal clonidine prolongs total duration of spinal bupivacaine analgesia. However, there are contradictory reports about its effect on maternal blood pressure and only limited data are available on fetal and neonatal outcome. In this study, we evaluated the efficacy of spinal clonidine combined with ropivacaine and sufentanil and its ...
El-Mas Mahmoud M - - 2004
The present study investigated the influence of 12-week ovariectomy (OVX) and estrogen supplementation (OVXE2) on the acute effects of the centrally acting antihypertensive agent clonidine on blood pressure, hemodynamic variability, and locomotor activity in Sprague-Dawley rats. The effects of estrogen depletion and repletion on the peripherally mediated hypotensive response to ...
Gulec S - - 2004
BACKGROUND AND OBJECTIVE: Clonidine has cardiac and systemic effects that can modify the potentially lethal cardiovascular effects of local anaesthetics. We evaluated the effects of clonidine pre-treatment on cardiotoxicity induced by an infusion of bupivacaine or ropivacaine and the success rate of resuscitation in anaesthetized rats. METHODS: Thirty-two Sprague-Dawley rats ...
El-Mas Mahmoud M - - 2004
Our previous studies have demonstrated that acute ethanol administration counteracts imidazoline I(1) receptor but not alpha(2)-adrenoceptor-mediated hypotension in spontaneously hypertensive rats (SHR). In the present study, we investigated the effect of chronic ethanol administration on hypotensive responses elicited by acute administration of selective imidazoline I(1) receptor (rilmenidine) or alpha(2)-adrenoceptor (alpha-methyldopa) ...
Tauzin-Fin P - - 2004
BACKGROUND: Laparoscopic surgery for phaeochromocytoma can cause excessive catechol amine release with severe hypertension and sinus tachycardia. i.v. calcium antagonists may be used to prevent increases in blood pressure during phaeochromocytoma resection. We investigated the effects of perioperative alpha(1) adrenergic block with urapidil on intraoperative haemodynamic events. The aim was ...
Maruyama Koichi - - 2004
Clonidine premedication prevents tourniquet pain and reduces sympathetic nerve activity. We evaluated hemodynamic changes and catecholamine release following tourniquet deflation during spinal anesthesia in patients who received oral clonidine premedication. The final analysis included 24 otherwise healthy patients undergoing lower-limb surgery randomly assigned to two groups: those receiving approximately 5 ...
Morin Astrid M - - 2004
BACKGROUND: In many studies investigating measures to attenuate the hemodynamic and humoral stress response during induction of anaesthesia, primary attention was paid to the period of endotracheal intubation since it has been shown that even short-lasting sympathetic cardiovascular stimulation may have detrimental effects on patients with coronary artery disease. The ...
Bousquet P - - 2003
Clonidine-like drugs (hybrid drugs) reduce blood pressure by acting centrally at both alpha(2)-adrenergic receptors (alpha(2)AR) and I(1) receptors (I(1)R). Some attempts at cloning I(1)R have failed, probably because of the lack of selectivity of the ligands. Recently, compounds acting exclusively at I(1)R were synthesized: LNP 911, LNP509, and S23515. For ...
Sinclair Melissa D - - 2003
Medetomidine is a relatively new sedative analgesic drug that is approved for use in dogs in Canada. It is the most potent alpha2-adrenoreceptor available for clinical use in veterinary medicine and stimulates receptors centrally to produce dose-dependent sedation and analgesia. Significant dose sparing properties occur when medetomidine is combined with ...
Marthol H - - 2003
BACKGROUND: Patients with familial dysautonomia (FD) frequently experience hypertensive crises after gastrostomy feeding. The central alpha2-agonist clonidine attenuates feeding-induced crises. The aim of this study was to assess the effect of clonidine on cardiovascular autonomic modulation and particularly baroreflex sensitivity in familial dysautonomia after gastrostomy feeding. MATERIAL AND METHODS: In ...
Gerra Gilberto - - 2003
The present study investigated clinical, cardiovascular and neuroendocrine consequences of rapid opioid detoxification (ROD) in heroin-dependent individuals, affected, or not, by comorbid antisocial personality disorder (ASPD). Thirty-two patients underwent ROD and subsequent treatment with daily naltrexone: 3 days detoxification procedures were performed utilizing clonidine, baclofen, oxazepam and ketoprofene, without anaesthesia. ...
Ikeda Yoshikazu - - 2003
Epidural administration of clonidine induces hypotension and bradycardia secondary to decreased sympathetic nerve activity. In this study, we sought to elucidate the change in baroreflex response caused by epidural clonidine. Thirty-six cats were allocated to six groups (n = 6 each) and were given either thoracic epidural clonidine 4 micro ...
Burstal R - - 2003
A pilot study was conducted using a simulated epidural test dose to ascertain the effects adrenaline, adrenaline/clonidine mixture, and clonidine alone on the accepted criteria for determining the occurrence of an epidural intravascular injection. Seventy-five ASA 1 or 2 children aged from six months to twelve years were sequentially allocated ...
Talke Pekka - - 2003
BACKGROUND: alpha(2)-Adrenoceptors mediate both sympatholytic and vasoconstrictive hemodynamic effects. The goal of this study was to profile the peripheral vasoconstrictive effects of a selective alpha(2)-adrenoceptor agonist in isolation from the sympatholytic effects it also induces. METHODS: The authors administered increasing plasma target concentrations of dexmedetomidine (0.075, 0.15, 0.3, and 0.6 ...
Halliwill John R - - 2003
In sedentary individuals, postexercise hypotension following a single bout of aerobic exercise is due to an unexplained peripheral vasodilatation. We tested the hypothesis that alpha-adrenergic responsiveness in the forearm and leg vasculatures is blunted during postexercise hypotension. We studied 12 men and two women before and 30 min after a ...
Hashimoto Junichiro - - 2003
OBJECTIVE: To clarify the effects of bedtime administration of the centrally acting alpha(2)-agonists, guanabenz and clonidine, on morning hypertension. METHODS: Patients with morning hypertension were assigned to receive once-daily evening administration of guanabenz (2 mg/day, n = 81; 4 mg/day, n = 2) or clonidine (75 microg/day, n = 40; ...
Volkow Nora D - - 2003
RATIONALE: The cardiovascular effects of psychostimulant drugs (methylphenidate, amphetamine, cocaine) have been mostly associated with their noradrenergic effects. However, there is some evidence that dopaminergic effects are involved in the cardiovascular actions of these drugs. Here, we evaluated this association in humans. METHODS: Positron emission tomography (PET) and [(11)C]raclopride, a ...
Ishiyama Tadahiko - - 2003
We studied the pressor and tachycardiac responses to ephedrine in elderly and young patients given either clonidine or midazolam during propofol anesthesia. In the first experiment, elderly (>60 yr) and young (20-45 yr) patients were randomly allocated to one of four groups according to age and premedicated regimens (n = ...
Herbert Michael K - - 2002
BACKGROUND: Inhibition of intestinal peristalsis is a major side effect of drugs used for anesthesia or for analgesia and sedation of patients in the intensive care unit. This in vitro study examined the effect of clonidine and dexmedetomidine on intestinal peristalsis and analyzed some of their mechanisms of action. METHODS: ...
Birkenfeld Andreas L - - 2002
BACKGROUND: Sibutramine, a serotonin and norepinephrine transporter blocker, is widely used as an adjunctive obesity treatment. Norepinephrine reuptake inhibition with sibutramine conceivably could exacerbate arterial hypertension and promote cardiovascular disease. METHODS AND RESULTS: In 11 healthy subjects (7 men, age 27+/-2 years, body mass index 23.1+/-0.7 kg/m2), we compared the ...
Takashima Yutaka - - 2002
To investigate the association of smoking habits with blood pressure (BP) and intraocular pressure (IOP), and to examine whether the smoking-BP association is related to the IOP level. This study was conducted on the basis of a cross-sectional design using annual health check-up data during one-year between August, 1999 and ...
Backo Angel L - - 2002
To report a case of possible clonidine-induced hypertension (by Naranjo score) in a patient with a C4 spinal lesion. Clonidine is a medication long used to treat hypertension, and it is still used in the treatment of refractory hypertension. Although effective, clonidine use is hindered by adverse effects and its ...
Stensløkken K-O - - 2002
Little is known of the cardiovascular functions of prostaglandins in non-mammalian vertebrates. There are indications that prostaglandins may have a function in haemostasis by constricting blood vessels in filament arteries in the fish gill after injury. Our aim was to examine the cardiovascular effect of the prostaglandins F(2 alpha) (PGF(2 ...
Stine Susan M - - 2002
BACKGROUND: Alteration in noradrenergic regulation as well as alteration in the hypothalamic-pituitary-adrenal (HPA) axis have been associated with opioid dependence and acute abstinence symptoms. METHODS: This double-blind, placebo-controlled study evaluated subjective, physiologic, and biochemical responses to yohimbine (.4 mg/kg, IV) in eight patients receiving methadone and compared results to those ...
Victor Ronald G - - 2002
PURPOSE: Clonidine, an alpha(2)-adrenergic agonist, raises blood pressure in patients with autonomic failure, in whom failure of reflex neurogenic venoconstriction leads to severe orthostatic hypotension. Because animal studies suggest that postjunctional alpha(2)-adrenoreceptors are located mainly on venous capacitance rather than arterial resistance vessels, we tested the hypothesis that venoconstriction is ...
Prisant L Michael - - 2002
The clonidine transdermal therapeutic system is being used as a therapy for blood pressure treatment. Systemic side effects seem to be fewer than with oral clonidine. However, localized skin reactions occur frequently and the incidence increases with the dose and duration of use. Common signs include erythema, scaling, vesiculation, excoriation, ...
Zalunardo Marco P - - 2002
Although the mechanism of tourniquet-induced hypertension is still unclear, plasma norepinephrine concentrations continuously increase in parallel to arterial blood pressure during tourniquet inflation. Clonidine attenuates hyperadrenergic and hyperdynamic responses. We investigated the effects of clonidine on prolonged tourniquet inflation. Twenty-nine patients scheduled for elective orthopedic surgery were randomly assigned to ...
Brune Michael E - - 2002
Fiduxosin is an alpha(1)-adrenoceptor antagonist with higher affinity for alpha(1A)-adrenoceptors and for alpha(1D)-adrenoceptors than for alpha(1B)-adrenoceptors. Our hypothesis is that such a compound with higher affinity for subtypes implicated in the control of lower urinary tract function and lower affinity for a subtype implicated in the control of arterial pressure ...
Schindler C W - - 2002
Conscious squirrel monkeys were treated i.v. with cocaine and various dopamine agonist drugs. Cocaine produced a dose-dependent increase in blood pressure, heart rate, and the rate-pressure product (RPP). The dopamine D1 receptor agonist (+/-)-6-chloro-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF 82958) produced effects comparable to cocaine. The D1 agonist (+/-)-6-chloro-7, 8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF 81297) ...
Michaluk Jerzy - - 2002
It is well recognized that 1,2,3,4-tetrahydroisoquinoline (TIQ) is a substance capable of inducing in animals a syndrome, regarded as an animal model of Parkinson's disease. This study was designed to evaluate the effect of the endogenous neurotoxin TIQ on the brain noradrenaline (NA) metabolism in mice and on an arterial ...
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