Search Results
Results 451 - 500 of 1007
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Irwin R P - - 1992
Blood pressure effects of i.v. levodopa were examined in parkinsonian patients with stable and fluctuating responses to levodopa. The magnitude of the hypotensive effect of levodopa was concentration dependent and was fit to an Emax model in fluctuating responders. Stable responders demonstrated a small hypotensive response. Baseline blood pressures were ...
Eisenach J C - - 1992
Intraspinally administered alpha 2-adrenergic agonists are being examined for postoperative analgesia, yet their effects on the hemodynamic response to acute hemorrhage have not been examined. In this study chronically prepared conscious sheep received thoracic intrathecal saline or clonidine 300 micrograms followed in 15 min by rapid removal of 1,000 ml ...
Griesbacher T - - 1992
In order to extend the in vivo pharmacological profile of CP-96,345 ((2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)- methyl)-1-azabicyclo[2.2.2]octan-3-amine dihydrochloride), a non-peptide antagonist of substance P, the compound was tested against substance P-induced effects on blood pressure in rabbits and on respiration pressure in guinea-pigs. In addition, CP-96,345, and its inactive (2R,3R)-enantiomer, CP-96,344, were also tested ...
Yüksel N - - 1992
We performed a prospective, randomized double blind study comparing the cardiovascular and intraocular pressure (IOP) effects of unilateral therapy with clonidine 0.125% and apraclonidine hydrochloride 1.0% in 15 normal and 15 ocular hypertensive volunteers. Baseline values were obtained prior to instillation. One drop of test medication (clonidine, apraclonidine or placebo) ...
Banerjee M - - 1992
We determined the effects of 8-epiprostaglandin (PG) F2 alpha, a noncyclooxygenase free radical-catalyzed product of arachidonic acid, on pulmonary vascular tone, its potency, and its mechanism of action. 8-Epi-PGF2 alpha (0.5-20 micrograms) was injected into the pulmonary artery (PA) catheter of 10 rabbits whose lungs were perfused in situ with ...
Kramer B A - - 1992
Twelve patients receiving ECT consented to random assignment to either intravenous or intramuscular administration of atropine for a total of 48 ECTs. There were no statistically significant differences between routes of administration in heart rate, blood pressures, or sialorrhea, but intravenous administration eliminated one injection per treatment and the development ...
Filos K S - - 1992
In a small number of studies and isolated case reports, intrathecally administered clonidine has been reported to relieve intractable cancer pain and to prolong spinal anesthesia induced by various local anesthetics. A double-blind placebo-controlled clinical trial was carried out in order to evaluate the effect of intrathecal clonidine on pain ...
Evans R G - - 1992
In conscious rabbits an inferior vena caval cuff was progressively inflated so cardiac output fell at a constant approximately 8% of its baseline value. There was a biphasic haemodynamic response, consisting of an initial compensatory phase during which there was progressive systemic vasoconstriction and tachycardia, followed by a decompensatory phase ...
Rubio G - - 1992
The effect of relapse to opiate use on blood pressure and heart rate has been studied in heroin-withdrawn addicts treated with clonidine in an outpatient detoxification procedure. The daily dose of clonidine was established according to body weight and amount of heroin usually consumed at the onset of treatment. Patients ...
Jarvis D A - - 1992
Clonidine, an alpha 2-adrenergic agonist, can potentiate opioid-induced analgesia. In a double-blind placebo-controlled study in human volunteers, we sought to determine whether clonidine also potentiates opioid-induced respiratory depression. Hypercapnic ventilatory responses (minute ventilation, mean inspiratory flow rate, and mouth occlusion pressure) were measured in five healthy male volunteers on two ...
Evans R G - - 1992
We tested whether a brainstem serotonergic mechanism influences the hemodynamic response to acute central hypovolemia. An inferior vena caval cuff was gradually inflated so that mean cardiac index (MCI) fell at a constant rate (approximately 8%/min). Under control conditions, mean systemic vascular conductance index (MSVCI) fell progressively until MCI had ...
Grohs J G - - 1992
1. Antihypertensive effects resulting from alpha 1-adrenoceptor blockade and stimulation of central nervous 5-HT1A receptors were compared with the effects arising from stimulation of 5-HT1A receptors alone during arterial hypertension. 2. Urapidil and 5-methyl-urapidil were less effective in decreasing arterial blood pressure than the lowest dose of the selective 5-HT1A ...
Weidler D - - 1992
This four-center, 20-week, open-label study evaluated transdermal clonidine as an adjunct to enalapril 10 mg daily and demonstrated patterns of compliance. Seventy-four mildly to moderately hypertensive patients (mean seated blood pressure, 150/101 mm Hg) received enalapril 10 mg once daily as initial monotherapy. In 66 patients, the seated diastolic blood ...
Foltin R W - - 1992
Intravenous cocaine (COC) and morphine (MOR) combinations ("speedballs") were administered to nine research volunteers during 12 daily experimental sessions. During each session, a single dose of MOR sulfate (0, 5 and 10 mg/70 kg) was administered i.v. in combination with a single dose of COC hydrochloride (0, 8, 16 and ...
Smith B D - - 1992
Epidural clonidine produces analgesia in humans with acute and chronic pain. Its use is limited because of short-lasting analgesia, hemodynamic depression, sedation, and respiratory depression. Intrathecal guanfacine has a longer duration of action than intrathecal clonidine. The present study compares these two drugs administered epidurally. Pulmonary artery, carotid artery, and ...
de La Coussaye J E - - 1992
The ability of clonidine and dobutamine to correct bupivacaine-induced cardiac electrophysiologic and hemodynamic impairment was evaluated in an experimental electrophysiologic model on closed-chest dogs. Five groups (n = 6) of pentobarbital-anesthetized dogs were given atropine (0.2 mg/kg IV). Group 1 was given a saline solution; all other dogs were given ...
van Essen E J - - 1992
The pharmacokinetics of epidural clonidine 150 micrograms was studied in 13 patients who had undergone abdominal hysterectomy. Plasma clonidine concentrations were measured up to 19 h in eight patients. In another five patients frequent blood sampling was performed only during the first 20 min to define early vascular uptake better. ...
Roulot D - - 1992
The aim of the present study was to examine the short- and long-term effects of the alpha 2-agonist clonidine on sympathetic overactivity, systemic, splanchnic, and renal circulation changes, and abnormal renal sodium excretion in cirrhotic patients with ascites. Of 17 patients, 8 received clonidine and 9 a placebo. Measurements were ...
Hieble J P - - 1992
1. SK&F 104856 (2-vinyl-7-chloro-3,4,5,6-tetrahydro-4- methylthieno[4,3,2ef][3]benzazepine) is a novel postjunctional alpha 1- and alpha 2-adrenoceptor antagonist. 2. SK&F 104856 as well as prazosin and SK&F 86466 reduced blood pressure in the anaesthetized normotensive dog. 3. SK&F 86466 and rauwolscine but not SK&F 104856 or prazosin, produced a marked increase in myocardial ...
Esler M - - 1992
OBJECTIVE: To study disturbances in sympathetic nervous system function in patients with alcoholic cirrhosis and the effect of clonidine on such disturbances. DESIGN: Cross-sectional physiologic and neurochemical evaluation of patients with cirrhosis and of healthy controls; an uncontrolled trial of intravenous clonidine in the cirrhotic patients. PATIENTS: Forty-four hospitalized patients ...
Ricci D - - 1992
The aim of the present work was to analyse the cardiovascular responses induced by i.c.v. administration of the alpha 1- and alpha 2-adrenoceptor agonists, phenylephrine and clonidine, respectively, in conscious normal and sinoaortic-denervated rats. Sinoaortic denervation involves changes in central and peripheral catecholaminergic pathways. Clonidine (1-10 micrograms) produced a dose-dependent ...
Saeki S - - 1992
In halothane (0.9%)-anesthetized rats, the immersion of the tail in 52.5 degrees C or 60 degrees C water for 15 sec resulted in a short-latencied tail jerk and a subsequent tachycardia and elevation in blood pressure. The i.t. administration of the alpha-2 agonists, dexmedetomidine (DMET), clonidine (CLON) and ST-91, resulted ...
Abdel-Rahman A A - - 1992
This study tested the hypothesis that aortic baroreceptors exert a central restraining influence on centrally mediated depressor responses and that this mechanism is tonically active and is independent of their modulation of basal arterial pressure. The effects of short-term (48-72 h) aortic baroreceptor deafferentation (ABD) on the acute hemodynamic (peripherally ...
Coplan J D - - 1992
To assess the role of noradrenergic stimulation during lactate-induced panic, ten patients with panic disorder who panicked during a standard sodium-lactate infusion underwent a repeat infusion following intravenous clonidine pretreatment. Although clonidine significantly lowered prelactate systolic blood pressure, the drug did not significantly lower prelactate anxiety levels, as reflected by ...
Atkin S H - - 1992
This study was designed to compare the clinical efficacy and safety of oral clonidine and oral labetalol in the treatment of severe hypertension in an emergency department setting. Thirty-six patients with severely elevated blood pressure (mean baseline blood pressure 199/132 mm Hg) without acute end-organ dysfunction were treated with either ...
Porchet H C - - 1992
Although clonidine analgesia appears to be mediated by the same central alpha 2-adrenoceptors that mediate its hypotensive effect, it is short-lasting when compared to the fall in blood pressure. This has been investigated by combined pharmacokinetic-pharmacodynamic analysis in 10 healthy volunteers who received (double-blind and crossover) clonidine 200 micrograms orally ...
Hamilton C A - - 1992
Rabbits were treated with guanabenz, clonidine and rilmenidine for 6 days via osmotic minipumps. Blood pressure, heart rate and responses to intracisternal clonidine were measured after 1 and 6 days treatment. Radioligand binding to forebrain and hindbrain membranes after 6 days treatment was examined using [3H]yohimbine to measure the number ...
Borbe H O - - 1991
Naftopidil, a novel antihypertensive compound, possesses 5-HT1A agonistic properties in addition to being an alpha 1-adrenoceptor antagonist. The IC50 values for alpha 1-adrenoceptors (235 nmol/l) and for 5-HT1A receptors (108 nmol/l) lie in the same concentration range. The reduction in blood pressure of anesthetized cats by 8-OH-DPAT and urapidil was ...
Schafers R F - - 1991
1. Abanoquil (UK 52,046) is a novel, quinoline-derivative, alpha 1-adrenoceptor antagonist which, on the basis of animal studies, possesses antiarrhythmic activity at doses which have little or no effect on blood pressure. 2. In two placebo-controlled, double-blind, crossover studies the alpha 1-adrenoceptor antagonist activity (phenylephrine pressor responses) and the effects ...
Schafers R F - - 1991
1. This study further examines the quinoline-derivative abanoquil with particular respect to the duration of its alpha 1-adrenoceptor antagonist activity and its concentration-effect relationship following a single intravenous bolus dose of 0.5 micrograms kg-1 in young, normotensive males. 2. alpha 1-adrenoceptor antagonism (as assessed by phenylephrine pressor responses) was detectable ...
Yorikane R - - 1991
Antiarrhythmic and cardiovascular profiles of a fused indole compound, (3aR,12R,12aR,12bS)-12-amino-2,3,3a,4,11,12,12a,12b -octahydro- 10-hydroxyisoquino [2,1,8-lma]carbazol-5(1H)-one hydrochloride 1.5 hydrate (RS-2135, CAS 133775-36-7), were investigated in anesthetized dogs. Class I antiarrhythmic agents such as disopyramide, lidocaine, mexiletine and flecainide were used as reference compounds. RS-2135 exerted more potent antiarrhythmic activity than reference compounds against ...
Dabiré H - - 1991
The systemic and regional hemodynamic effects of the selective 5-HT1A receptor agonist flesinoxan (3-300 micrograms/kg, i.v., in cumulative doses) were investigated in normotensive anesthetized and pithed rats using a pulsed Doppler system and were compared to those of the alpha 2-adrenoceptor agonist clonidine. In anesthetized rats, flesinoxan and clonidine induced ...
Sporton S C - - 1991
1. The effects of microinjections (100 nl) into the dorsal motor vagal nucleus of the 5-HT1A receptor agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and flesinoxan, the 5-HT2 receptor agonist (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), the 5-HT3 receptor agonist phenylbiguanide (PBG), the alpha 2-adrenoceptor agonist clonidine and the excitatory amino acid glutamate on heart rate, blood ...
Kooner J S - - 1991
The contribution of neurogenic mechanisms in maintaining hypertension was investigated in 13 patients with unilateral renal artery stenosis (twelve with normal, one with grossly elevated plasma renin levels) by determining the haemodynamic and hormonal responses to the centrally acting sympatholytic agent, clonidine. The same patients were studied after captopril to ...
Knoll-Köhler E - - 1991
Since knowledge of the bioavailability of adrenaline from the intraoral submucosal depot is a prerequisite for its safe use in dentistry, the time-dependent effects of adrenaline on the plasma adrenaline level and cardiohaemodynamic parameters were studied with invasive methods in adrenalectomized, anaesthetized rats after injection of adrenaline (4.0 micrograms/kg body ...
Ooi R - - 1991
The effects of clonidine, an alpha 2 adrenergic agonist, on ventilation were studied in a group of adult volunteers. The ventilatory variables measured were minute ventilation, respiratory rate, end-tidal carbon dioxide tension and the response to carbon dioxide challenge. We found no differences in minute ventilation, respiratory rate and end-tidal ...
Kooner J S - - 1991
BACKGROUND: Clonidine, a partial presynaptic and postsynaptic alpha-adrenoceptor agonist, has been shown to lower blood pressure in normal subjects but not in tetraplegics; however, the mechanisms of this action have not been elucidated. METHODS AND RESULTS: The hemodynamic and hormonal basis of the hypotensive action of clonidine was investigated in ...
Lueg M C - - 1991
An open-label study was conducted to evaluate the clinical safety and efficacy of transdermal clonidine as an adjunct to sustained-release (SR) diltiazem (90 mg twice daily) in mild-to-moderate hypertension. Ninety patients with a mean baseline sitting blood pressure of 154/102 mmHg were given 90 mg of diltiazem SR twice daily ...
Overton J M - - 1991
Corticotropin-releasing factor (CRF) modifies cardiovascular function and hemodynamic status after administration into the central nervous system and into the peripheral circulation. The mechanisms by which CRF alters arterial pressure and heart rate have been examined in detail whereas little information exists regarding the processes mediating CRF-induced changes in regional blood ...
Du Z Y - - 1991
1. The effect of tolerance to glyceryl trinitrate (GTN) on vasodilator and vasoconstrictor responses was examined in conscious rabbits and isolated rabbit aortic rings. 2. In conscious rabbits, depressor responses to 5 min infusions of GTN (10-40 micrograms/kg per min intravenously (i.v.)), sodium nitroprusside (SNP, 5-20 micrograms/kg per min i.v.) ...
Penon C - - 1991
The authors studied the effects of epidural clonidine (300 micrograms) on circulation and ventilatory control in seven healthy unpremedicated subjects. After clonidine injection, arterial blood pressure decreased significantly in all subjects (range, 13%-25% for systolic blood pressure and 13%-32% for diastolic blood pressure). Heart rate decreased significantly by 10%-16% between ...
Mandal A K - - 1991
Our study had three purposes: 1) to determine whether 5-methyl-urapidil, topically applied to the ventrolateral medulla, produces hypotension by activating serotonin-1A (5-HT1A) receptors, 2) to determine whether 5-methyl-urapidil given i.v. produces hypotension in part by activating 5-HT1A receptors in the ventrolateral medulla, and 3) to determine the specific site within ...
Laurito C E - - 1991
STUDY OBJECTIVE: To determine the effects of oral clonidine premedication on sedative, anxiolytic, and hemodynamic responses during the immediate preoperative period, laryngoscopy/intubation, and postanesthetic recovery. DESIGN: Randomized double-blind assignment to one of four treatment groups (clonidine 0.1 mg, clonidine 0.2 mg, triazolam 0.25 mg, or placebo); n = 10 per ...
Martí-Cabrera M - - 1991
The intravenous infusion of mannitol (1.37 mosm kg-1 min-1 during 4 min) to anesthetized, open-chest, intact dogs produced a hemodynamic response characterized by a positive inotropic effect and a decrease in total peripheral resistance. This response is attributable to a direct effect of hypertonicity (plasma osmolality raised from 309 +/- ...
Eisenach J C - - 1991
Intrathecally administered alpha 2-adrenergic agonists produce analgesia in humans but may also produce hypotension and bradycardia. To further characterize hemodynamic depression produced by intrathecally administered alpha 2-adrenergic agonists, clonidine (100-1,500 micrograms) was injected into the cervical, thoracic, or lumbar intrathecal space of conscious sheep. Only thoracic intrathecal clonidine injection (100 ...
Barnes J C - - 1991
The in vivo central effects of a range of full and partial muscarinic receptor agonists have been investigated on hippocampal theta rhythm and blood pressure. In the isoflurane-anaesthetised rat, pretreated with N-methylscopolamine, i.v. administration of arecoline, oxotremorine, arecaidine propargyl ester, aceclidine and pilocarpine produced dose-dependent increases in the frequency of ...
Wilson T W - - 1991
Between 1975 and 1988, demographic data, weight and height measurements, and blood pressure readings were obtained for 77 890 residents of Saskatchewan (about 7.6% of the population). High readings were present in 7.8% of those surveyed, but prevalence fell over the lifetime of the survey. Subjects whose drug therapy was ...
Tomlinson B - - 1991
Intravenous urapidil, 40 mg bolus followed by an infusion of 18 mg.h-1 for 2 h was administered to 6 female non-patient volunteers. Randomised cumulative dose response curves to angiotensin, phenylephrine and isoprenaline were performed before and commencing 30 min after the start of the infusion of urapidil. Urapidil significantly reduced ...
Bernard J M - - 1991
The effects of clonidine, a central alpha 2-adrenoreceptor agonist, on haemodynamic and catecholamine changes were assessed during emergence from anaesthesia, a period which is associated with increased sympathetic nervous discharge, hypertension and tachycardia. According to a double-blind randomized design, 32 patients received either clonidine, preoperatively given by oral route (3.5 ...
Glue P - - 1991
The effects of alpha 2-adrenoceptor agonists and antagonists on saccadic eye movements were studied in normal volunteers using the agonist clonidine and the antagonist idazoxan. Changes in blood pressure, heart rate, and several psychological self-ratings were also recorded. Clonidine produced marked slowing of peak saccade velocity, acceleration and deceleration, with ...
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