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Results 251 - 300 of 980
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Poisson D - - 2000
Numerous studies have addressed the antihypertensive properties of I(1)-imidazoline receptor agonists such as moxonidine, but very few authors examined their cardiac antiarrhythmic potency. Due to the important role of the sympathetic nervous system in the genesis of neurogenic cardiac arrhythmias, we investigated the antiarrhythmic effects of moxonidine and compared them ...
Dodick D W - - 2000
The clinical syndrome of hypertension, headache, palpitation, diaphoresis, flushing, and emotional lability is classically associated with pheochromocytoma. Two patients are presented with this constellation of symptoms in whom investigations for pheochromocytoma were unrevealing. Headache was the presenting and most prominent complaint, with daily episodes of short-lasting, intermittent, and paroxysmal attacks. ...
Phillips M A - - 2000
RATIONALE: Spontaneous fluctuations in the size of the pupil in darkness are a recognized index of sleepiness, and these fluctuations can be quantitatively measured using the pupillographic sleepiness test (PST). The central noradrenergic system is believed to play a role in the maintenance of alertness, and there is evidence that ...
Matot I - - 2000
The usual haemodynamic response to fibreoptic bronchoscopy is an increase in heart rate and blood pressure. We therefore compared, in a prospective, randomised, double-blind study, the effect of two doses of oral clonidine premedication (150 microg or 300 microg) with placebo (control group) on the haemodynamic alterations in 62 patients ...
Wang H - - 2000
Injection of the pineal indoles melatonin, 5-methoxytryptophol and 5-methoxytryptamine via the external jugular vein elicited a dose-dependent depression in mean arterial pressure. Melatonin and 5-methoxytryptophol were approximately equipotent and a dose of 150 micromol/kg brought about a reduction of about 40 mmHg in mean arterial pressure. Methoxytryptamine exerted a much ...
Geyer O - - 2000
PURPOSE: The aim of this study was to determine allergic responses to clonidine hydrochloride 0.25% in glaucoma patients with proven allergic reaction to apraclonidine 0.5%. METHODS: Fifteen consecutive glaucoma patients with allergic reaction to apraclonidine were prospectively challenged with clonidine hydrochloride 0.25% and evaluated for recurrence of allergic reactions and ...
Marinangeli F - - 2000
The study evaluated the effects of premedication with intravenous clonidine on thiopental or propofol requirements for induction and haemodynamic changes associated with both induction and endotracheal intubation. Clonidine administered intravenously before induction of anaesthesia reduced propofol or thiopental requirements. The association of clonidine and propofol caused, after injection of the ...
Roche W J - - 2000
Hypertension in the patient with SCI is relatively rare and generally restricted to patients with high-level injuries where autonomic dysreflexia can occur. Resting blood pressure in individuals with SCI has been described as lower than that in the normal population. This report describes five previously normotensive teenagers with subsequent paraplegia ...
Eisenach J C - - 1999
BACKGROUND: alpha2-Adrenergic agonists produce analgesia primarily by a spinal action and hypotension and bradycardia by actions at several sites. Clonidine is approved for epidural use in the treatment of neuropathic pain, but its wider application is limited by hemodynamic side effects. This study determined the antinociceptive and hemodynamic effects of ...
Petersson M - - 1999
Oxytocin treatment decreases blood pressure and changes the pattern of spontaneous motor activity. The aim of this study was to explore if alpha 2-adrenoreceptors that are involved in the regulation of blood pressure and spontaneous motor activity are influenced by oxytocin treatment. For this purpose, male rats were pretreated with ...
Goenka S - - 1999
We report a case of a neonate who developed hypotension immediately after birth, and needed dopamine infusion to sustain his blood pressure and tissue perfusion. He developed cyanosis of his extremity immediately after dopamine was started via peripheral line and improved spontaneously after dopamine was stopped. This happened repeatedly at ...
Iriuchijima J - - 1999
The aim of this study was to find vascular areas where clonidine decreases the regional vascular resistance when this drug lowers arterial pressure in conscious spontaneously hypertensive rats and normotensive control rats. Arterial pressure was observed with an indwelling catheter at a carotid. Blood flow was measured with an electromagnetic ...
Prichard B N - - 1999
Moxonidine is a centrally acting antihypertensive. Its action is mediated by imidazoline I1 receptors located in the rostral ventro-lateral medulla (RVLM). Animal experiments show that much smaller amounts are required to reduce blood pressure (BP) when it is given intracisternally, or injected directly into the RVLM, compared to intravenous dose. ...
Mo W - - 1999
Cocaine causes hypertension at least in part by stimulating the sympathetic nervous system, but it is not clear if this effect is centrally or peripherally mediated. To address this issue we studied the vasoconstrictive effect of cocaine in vivo and in isolated artery segments. In vivo cocaine increased mean arterial ...
Ohyama N - - 1999
We investigated the dose-response effects of phenylephrine and antagonistic effects of prazosin on axial movement of the rat incisor and arterial blood pressure. Phenylephrine caused a temporal extrusive tooth movement and an increase in blood pressure at all doses. With increasing phenylephrine doses, the maximum extrusive tooth movement and maximum ...
Hayakawa-Fujii Y - - 1999
We studied the hemodynamic effects of ephedrine in patients with or without clonidine premedication during either isoflurane or propofol anesthesia. Forty adult patients were randomly assigned to one of two groups: 20 patients received famotidine 20 mg orally (control group) and 20 received clonidine 3 microg/kg and famotidine 20 mg ...
Parlow J L - - 1999
Clonidine reduces postoperative circulatory instability in patients with essential hypertension. It also increases the sensitivity to vasopressors before and during anesthesia. We investigated blood pressure responses to phenylephrine and nitroprusside pre- vs postoperatively and the effect of clonidine on these responses in patients with essential hypertension. Twenty patients received clonidine ...
Lee J - - 1999
In a double-blind, randomized, placebo-controlled study, 41 patients received clonidine 3 micrograms kg-1 or placebo at induction of isoflurane and nitrous oxide in oxygen anaesthesia. Metoprolol was also given to achieve a systolic arterial pressure of 80 mm Hg. Requirements for metoprolol were significantly less in the clonidine group (P ...
Srilatha B - - 1999
The present investigation elucidates the deleterious effects of three prototypical antihypertensive drugs namely, propranolol, clonidine and captopril on the erectile physiology. In order to delineate the direct drug effects from vascular insufficiency inherent in hypertensive states, the study was conducted on a normotensive animal model. The adverse effects of these ...
Kariya N - - 1999
Clonidine, an alpha2 agonist, was administered through a nasogastric tube for the treatment of hypertension in a head-injury patient with elevated plasma catecholamines. Haemodynamic parameters were stabilized with a reduction in sympathetic nervous activity. The plasma clonidine concentration, measured by radioimmunoassay, rapidly increased following the administration. After cessation of oral ...
Parlow J L - - 1999
BACKGROUND: Patients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines ...
Mantz J - - 1999
Pharmacological manipulation of the sympathetic tone has led to the synthesis of novel compounds to control stress-induced hemodynamic disorders. The use of alpha(2)-adrenoceptor agonists is particularly interesting in this regard, since these agents decrease sympathetic activity by reducing norepinephrine release from nerve terminals. Dexmedetomidine is a potent, highly selective alpha(2)-adrenoceptor ...
Azevedo E R - - 1999
OBJECTIVES: We studied the effects of clonidine on cardiac sympathetic activity and left ventricular function in patients with congestive heart failure (CHF). BACKGROUND: Sympathetic activation has major prognostic implications in patients with heart failure. Clonidine, an imidazoline and alpha2-receptor agonist, has been shown to cause a reduction in generalized sympathetic ...
Dias V C - - 1999
The objective of this study was to assess the efficacy and tolerability of transdermal clonidine in inner-city African-American and Hispanic-American patients with essential hypertension. A multiclinic open-label, prospective trial for 12 weeks was used. Dose titration was based on office blood pressure (BP) measurements of > 140/90 mm Hg. Clinical ...
D'Amico M - - 1999
Endothelin-1 (ET-1) (10 pmol) microinjected into the superficial layer of superior colliculus induces decreases in blood pressure (control, 108 +/- 5 mmHg, n=6; ET-1, 71 +/- 4 mmHg, n=5). The effects on blood pressure induced by endothelin-1 were significantly (p<0.05) reduced by pre-administration into the superior colliculus of the alpha1-adrenoceptor ...
Savino E A - - 1999
The aim of the investigation was to examine the effects of cooling on the tail artery regarding the scarceness of such studies in spite of the essential thermoregulatory role played by this vessel. Segments of the proximal portion were suspended isometrically in medium containing 1.25 mM Ca. Lowering the temperature ...
Nurminen M L - - 1998
The effects of moxonidine on blood pressure, heart rate and sympathetic tone were studied in conscious spontaneously hypertensive rats. Intravenous moxonidine (80 nmol) transiently increased blood pressure without affecting heart rate or splanchnic nerve activity. Moxonidine (20-80 nmol) given into the fourth cerebral ventricle dose-dependently lowered mean arterial pressure, heart ...
Watanabe Y - - 1998
PURPOSE: To evaluate the effects of clonidine on responses to adrenoceptor agonists and baroreflex sensitivity, we examined arterial blood pressure (AP) responses to phenylephrine and heart rate (HR) responses to isoproterenol and baroreflex sensitivity (HR response to AP changes due to phenylephrine or nitroglycerin). METHODS: We studied 60 anaesthetized patients ...
Medvedev O S - - 1998
Earlier findings have shown that hypotensive effects of centrally acting drugs, such as clonidine, are enhanced in animals after denervation of arterial baroreceptors. The purpose of this study was to investigate the dynamic of changes in arterial pressure, heart rate and hypotensive effects of clonidine, rilmenidine and moxonidine in Wistar ...
Medvedev O S - - 1998
In the present study we investigated the chronopharmacological dependence of dose-dependent hypotensive and cardiochronotropic effects of the imidazoline-like drugs (clonidine, rilmenidine and moxonidine) in stroke-prone spontaneously hypertensive rats (SHR-SP), using radio-telemetric system (Data Sciences, USA). The 24-h blood pressure, heart rate and locomotor activity profiles showed peak values during the ...
Godwin S J - - 1998
In 10 conscious rabbits, the baroreceptor-heart rate (HR) reflex effects of centrally acting antihypertensive agents with high affinity for imidazoline receptors (IRs), moxonidine and rilmenidine, were compared with clonidine which acts predominantly via central alpha2-adrenoceptors. Dose regimens were chosen to give similar hypotension (-17+/-1 mm Hg) and bradycardia (-27+/-2 b/min) ...
Haastrup A T - - 1998
The dyslipidemia in obese hypertensive persons may contribute to their increased vascular alpha-adrenergic receptor reactivity and tone. To further examine this notion, we conducted 2 studies of pressor sensitivity to phenylephrine, an alpha1-adrenergic receptor agonist, in lean normotensive subjects. In the first study (n=6), pressor responses to phenylephrine were obtained ...
Mao L - - 1998
Previous studies from our laboratory demonstrated an antagonistic hemodynamic interaction between ethanol and clonidine in conscious and in urethane-anesthetized rats. The present study tested the hypothesis that ethanol produces its effect by counteracting clonidine-evoked inhibition of norepinephrine (NE) release at its major site of action, the rostral ventrolateral medulla (RVLM). ...
Bryant C E - - 1998
Medetomidine was administered to sheep and horses at a dose rate of 5 microg kg(-1) (i.v.). Heart rate and blood pressure were recorded. Medetomidine induced bradycardia and a biphasic blood pressure response consisting of a transient hypertension followed by hypotension. Administration of prazosin (an alpha1 adrenoceptor antagonist; 100 microg kg(-1), ...
Schuerch L V - - 1998
Human neuropeptide Y (hNPY) potentiates the postjunctional vasoconstrictor effects of alpha1-adrenoceptor agonists in animals and in human hand veins in vivo. We therefore hypothesized that such an interaction might also occur in the human arterial bed. With the present single-blind cross-over study in 12 healthy volunteers, the effect of subpressor ...
Benhamou D - - 1998
Seventy-eight pregnant women at term, scheduled for elective cesarean section, were enrolled in this multicenter trial to compare the analgesic efficacy and side effect profile of a spinal block with hyperbaric bupivacaine alone (Group B) or combined with 75 microg of clonidine (Group BC) or with clonidine 75 microg and ...
Winslow R M - - 1998
We have compared polyethylene glycol-modified bovine hemoglobin (PEG-Hb; high O2 affinity, high viscosity, high oncotic pressure) and human hemoglobin cross-linked between the alpha-chains (alpha alpha-Hb; low O2 affinity, low viscosity, low oncotic pressure) with a non-O2-carrying plasma expander (pentastarch, high viscosity and oncotic pressure) after a 50% (by volume) exchange ...
Jost W H - - 1998
Orthostatic hypotension is common in Parkinsonian patients. It is probably caused by reduced noradrenaline (NA) release. This effect is further enhanced by therapeutic use of ergot alkaloid dopamine agonists. In this trial we studied the impact of the non-ergot dopamine agonist ropinirole on blood pressure and noradrenaline release in 12 ...
Tanaka J - - 1998
To verify whether noradrenergic inputs to the subfornical organ (SFO) are involved in the control system of arterial pressure, we investigated the effects of blood pressure changes on noradrealine (NA) release in the SFO and its surrounding sites using microdialysis techniques in rats. Hemorrhage (5 or 10 ml/kg) significantly increased ...
Tagariello V - - 1998
BACKGROUND AND OBJECTIVES: Spinal mepivacaine has been reported as a reliable anesthetic for ambulatory anesthesia. Its pharmacologic properties are midway between those of bupivacaine and lidocaine, and it can be used in intermediate duration ambulatory surgical procedures. METHODS: A patient taking clonidine transdermal patches (TTS) to control high blood pressure ...
Taittonen M T - - 1998
The use of ketamine as a sole anesthetic induces marked central sympathetic stimulation, causing increased heart rate, blood pressure (BP), and oxygen consumption (VO2). Both alpha 2-agonists and benzodiazepines have been used to attenuate these potentially harmful ketamine-induced responses. This double-blind, randomized, placebo-controlled study was designed to compare the perioperative ...
Kimura T - - 1998
BACKGROUND: Clonidine reduces heart rate (HR) responses to atropine, whereas neostigmine causes bradycardia. This study was designed to determine whether clonidine premedication would reduce tachycardia after neostigmine-atropine administration. METHODS: Fifty adult patients without cardiovascular disorders who were scheduled for elective surgeries were randomly assigned to receive approximately 5 microg/kg (oral ...
Furuhata K - - 1998
T-3762, a newly developed fluoroquinolone antimicrobial agent, ciprofloxacin (CPFX) and ofloxacin (OFLX) were administered intravenously to anesthetized dogs by intravenous infusion, and blood pressure, heart rate and plasma histamine concentrations were monitored. T-3762 decreased blood pressure by 12.0%, without alterations in heart rate and plasma histamine concentration, only when infused ...
Costello T G - - 1998
The aim of this study was to compare hemodynamic responses to intubation and pin head-holder application in two groups of neurosurgical patients given oral clonidine (3 microg/kg) or oral temazepam (10-20 mg) 90 min before the induction of anesthesia. Fifty patients undergoing elective craniotomy were randomized to either group. Anesthesia ...
Mestivier D - - 1998
In spontaneously hypertensive rats (SHR), chronic infusion of clonidine failed to decrease blood pressure and blood pressure variability. We used nonlinear methods to get a deeper insight on the effects of clonidine on blood pressure dynamics. For 24 h and 4 wk, clonidine (0.1 mg . kg-1 . day-1 sc) ...
Conkin J - - 1998
The intensity of a pain-only decompression sickness (DCS) symptom with respect to time at altitude increases, peaks, and then declines in some cases. A similar pattern is also seen in a graph of the probability density function [f(t)] for DCS. The f(t) is the proportion of DCS per unit time ...
Beninger F G - - 1998
Blood pressure control is an important part of any surgical procedure and is especially important during rhytidectomy to reduce the risk of bleeding, improve visualization, and reduce the risk of postoperative fluid accumulations. For patients given general anesthetic, b blood pressure control is regulated by intravenous fluids, inhalational gas concentrations, ...
De Kock M - - 1998
In this prospective, nonblind study, we report the use of clonidine during orthotopic liver transplantation (OLT). Twenty adult patients in a stable medical condition were studied. General anesthesia consisted of isoflurane in air/oxygen and sufentanil. Patients in the clonidine group received a slow i.v. infusion (15 min) of 4 microg/kg ...
Chan T Y TY Division of Clinical Pharmacology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong - - 1998
The ranges of sodium and potassium intake and their relationship to blood pressure were studied in 126 healthy Chinese subjects (42 men, 84 women) aged between 20 and 65 years living in Hong Kong. An average of three blood pressure measurements and one to three 24-hour urinary sodium and potassium ...
Czapla M A - - 1998
The endogenous opioid peptides, endomorphin 1 and 2, are newly isolated, potent, and selective mu-opioid receptor agonists. In the present study, responses to endomorphin 1 and 2 were investigated in the systemic vascular bed of the rat. Endomorphin 1 and 2 induced dose-related decreases in systemic arterial pressure when injected ...
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