Search Results
Results 401 - 450 of 1007
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Mercadante S - - 1994
In obstetric patients treated with epidural analgesia during labor and delivery, shivering is quite frequent due to stress, vasodilatation, infusion of fluids, low ambient temperature, and the direct effect of solution injected into the epidural space. Sixty obstetric patients who developed shivering after receiving epidural analgesia for delivery were randomly ...
Lepage J Y - - 1994
We have studied the effects of urapidil 0.4 mg kg-1 i.v. and clonidine 2.5 micrograms kg-1 i.v. on left ventricular volume and function in 20 patients with chronic coronary artery disease and essential hypertension. Patients were studied using 99mtechnetium radionuclide angiography with first-pass and ECG-gated equilibrium blood-pool techniques and non-invasive ...
Goźlińska B - - 1994
The effect of 2-oxoglutarate aminotransferase inhibitor, aminooxyacetic acid (AOAA) on hypotension induced by clonidine in spontaneously hypertensive rats (SHR) was examined. AOAA given 15 min before clonidine significantly intensified clonidine--induced reduction of blood pressure. This effect reached its maximum within 120 min after AOAA administration, when AOAA itself had no ...
Zoukos Y - - 1994
We have studied beta-adrenoceptor number and affinity on peripheral blood mononuclear cells (PBMCs) in normotensives (NT) and hypertensives (HT), before and after intravenous administration of clonidine, an alpha 2-adrenoceptor agonist which lowers blood pressure predominantly by reducing central nervous system sympathetic outflow. After clonidine, there was a decrease in blood ...
Oloyede A - - 1994
We show that in the early stages of loading of the cartilage matrix extensive water exudation and related physicochemical and structural changes give rise to a distinctly consolidatable system. By enzymatically modifying the pre-existing osmotic condition of the normal matrix and measuring its hydrostatic excess pore pressure, we have studied ...
Prichard B N - - 1994
Moxonidine is an imidazoline receptor modulator, specific for the I1-imidazoline receptor. The stimulation of imidazoline receptors represents a new mode of antihypertensive action to inhibit peripheral alpha-adrenergic tone by a central mechanism. Acute hemodynamic studies reveal moxonidine produces an acute fall of blood pressure and systemic vascular resistance. Heart rate, ...
Blanc J - - 1994
1. Power spectral analysis of the frequency of wave-forms of blood pressure and heart rate was used to characterize short-term fluctuations of these parameters in three strains of conscious Lyon rat, normotensive (LL and LN) and hypertensive LH. 2. A mild stress produced by means of a jet of air ...
Del Rio G - - 1994
OBJECTIVE: Several studies indicate an inverse relationship between the sympathetic nervous system activity and thyroid function. Altered adrenoceptor sensitivity, particularly alpha 1 and beta, have been described in hypothyroid and hyperthyroid patients. No information in patients with thyroid disease is available on the main mechanism regulating sympathetic nervous system outflow, ...
Dehkordi O - - 1994
The current study was undertaken to evaluate the effects of cholinomimetic drugs on cocaine-induced central cardiorespiratory depression. Cats anesthetized by urethane (2.0 g/kg) were subjected to topical application at the caudal ventrolateral medullary surface (cVMS) of cocaine and two cholinomimetic pretreatment drugs. The following drug regimens were tested: 37 mM ...
Moore N - - 1994
Urapidil is an antihypertensive agent known to have central 5HT1A agonistic properties in addition to alpha-1 blocking effects. To assess the importance of these effects, we compared the hemodynamic effects of a single oral dose of urapidil (U, 60 mg) with those of prazosin (Pr, 2 mg), clonidine (Cl, 0.15 ...
Galbraith W M - - 1994
Rapid intravenous infusion of GEM 91, a 25-mer phosphorothioate oligonucleotide complementary to the gag site of HIV, in the monkey produces transient decreases in peripheral total WBC and neutrophil counts, hemoconcentration, and a brief increase followed by a prolonged decrease in arterial blood pressure. These changes are preceded by and ...
Feldman J - - 1994
In anaesthetized animals, systemic injection of ET1 at doses from 3 to 100 ng.kg-1 provoked only a transient hypotensive effect. At 300 ng.kg-1 we observed the classical biphasic effect, consisting of a transient lowering of the arterial pressure followed by a long-lasting hypertensive effect. Direct injection of the peptide into ...
Versteeg D H - - 1993
After the i.c.v. administration of 300 pmol ACTH-(1-24) or [Nle4,D-Phe7]alpha-MSH, a long-lasting increase in blood pressure was observed synchronously with the incidence of excessive grooming. Two structurally related peptides with no grooming behavior-inducing potency, ACTH-(7-16)-NH2 and gamma 2-MSH, in doses of 300 and 500 pmol, respectively, caused a slight and ...
Rauck R L - - 1993
BACKGROUND: Intraspinally administered alpha 2-adrenergic agonists may relieve pain in sympathetically maintained pain (SMP) syndromes, such as reflex sympathetically dystrophy (RSD), by spinal, peripheral, and central nervous system actions. This study examined analgesic efficacy and side effects of epidurally administered clonidine in patients with severe, refractory RSD. METHODS: Twenty-six patients ...
Burris J F - - 1993
Cardiovascular diseases are the leading causes of death in the United States, with hypertension being amongst the most prevalent of the cardiovascular risk factors. Improvement of hypertension management has, in consequence, received much attention. Extensive pre- and post-marketing experience with the transdermal formulation of clonidine marketed in the USA in ...
- - 1993
The clonidine patch offers for the first time the unique possibility of a once-a-week transdermal therapy of hypertension due to direct absorption of clonidine through the skin. The present study investigates the efficacy and safety of the transdermal administration on a sample of the Italian population. 101 patients entered the ...
Robertson D - - 1993
BACKGROUND: Baroreflexes originate in the great vessels of the neck and thorax and prevent arterial pressure from rising or falling excessively. METHODS: This study was undertaken to clarify the cause, clinical spectrum, and therapy of this disorder. We studied 11 patients with baroreflex failure presenting as severe, labile hypertension and ...
Watts S W - - 1993
Recent studies indicate that norepinephrine-induced contractile oscillations in the tail artery from stroke-prone spontaneously hypertensive rats (SHRSP) may be a vascular phenomenon independent of blood pressure level. The objectives of this study were: (1) to characterize pharmacologically the alpha-adrenoceptor mediating norepinephrine-induced oscillations in tail artery; and (2) to investigate the ...
Lee F W - - 1993
Intravenous infusions of nitroglycerin (GTN), 1,2-glyceryl dinitrate (1,2-GDN), and 1,3-glyceryl dinitrate (1,3-GDN) were given to four conscious dogs at 10 micrograms/min, 30 micrograms/min, 50 micrograms/min, and 70 micrograms/min of GTN and 20 micrograms/min and 100 micrograms/min of GDNs. The steady state plasma concentrations (Css) of GTN were reached after about ...
Kurihara J - - 1993
The influence of 5-min global cerebral ischemia on the facilitatory modulation of the vagal baroreflex through central alpha 2-adrenoceptors or by the electrical stimulation of the septum was investigated in anesthetized dogs. Reflex bradycardia was produced by a bolus injection of phenylephrine at a dose which produces about a 25-mmHg ...
Houston M C - - 1993
Calcium channel blockers and central alpha-agonists are among the classes of antihypertensive drugs that yield the most favorable overall effects on risk factors for hypertension-related end-organ damage. An open-label prospective trial in 42 patients with a mean baseline blood pressure of 144/102 mm Hg sought to assess the usefulness of ...
Bauer J A - - 1993
Hemodynamic rebound after abrupt withdrawal may be an important consideration associated with nitroglycerin (NTG) monotherapy. This phenomenon may arise from unopposed neurohormonal vasoconstriction because of rapid elimination of NTG. The role of NTG pharmacokinetics in the development of hemodynamic rebound was examined using a rat model of congestive heart failure. ...
Keipert P E - - 1993
This report describes acute changes in systemic blood pressure and urine output observed after a 50-percent isovolemic exchange transfusion (ET) with diaspirin-crosslinked hemoglobin (alpha alpha Hb). Stroma-free Hb was crosslinked between the alpha chains by using a 14C-labeled diaspirin, bis(3,5-dibromosalicyl)fumarate. Forty conscious, chronically cannulated rats underwent ET with 14C-labeled alpha ...
Lefèvre-Borg F - - 1993
1. Phenylephrine-induced contractions of rabbit isolated trigone and urethra were antagonized in a competitive manner by alfuzosin (pA2 7.44 and 7.30, respectively) and prazosin. 2. The characteristics of [3H]-prazosin binding to human prostatic adenoma tissue were evaluated. [3H]-prazosin was potently displaced by alpha 1-adrenoceptor specific agents including alfuzosin, its (+)- ...
Ono H - - 1993
Experiments were performed on intact and spinalized rats anesthetized with urethane and alpha-chloralose. In intact rats, administration of tizanidine (0.1 mg/kg, i.v.) decreased the mono- (MSR) and polysynaptic reflex potentials (PSR). Blood pressure was initially elevated and then lowered by tizanidine. Although pretreatments with hexamethonium and phentolamine prevented the tizanidine-induced ...
Rupniak N M - - 1993
We examined the ability of intravenous (i.v.) challenge with pentagastrin to induce behavioural and cardiovascular effects consistent with panic attack in conscious rhesus monkeys. For behavioural evaluation, 4 naive male rhesus monkeys familiar with minimal manual restraint necessary for drug administration received a rapid i.v. bolus of pentagastrin (4, 8 ...
Grossman E - - 1993
Yohimbine is an alpha 2-adrenoceptor antagonist that is FDA approved for treatment of impotence. The drug is an indolalkylamine alkaloid chemically similar to reserpine and is believed to act through sympatholysis. We examined effects of oral yohimbine on blood pressure (BP) and plasma levels of catechols in patients with essential ...
Doak G J - - 1993
Induction of anaesthesia is often associated with undesirable variations in blood pressure and heart rate. Clonidine has been demonstrated to attenuate many of these undesirable effects when used as a premedicant. Other alpha 2 adrenergic agonists have been used to ameliorate the cardiostimulatory effects of ketamine in animals but there ...
Jastrzebski Z - - 1993
The effect of the GABA agonist muscimol on the hypotensive action of clonidine in SHR was investigated. Muscimol administered before clonidine significantly (p < 0.01) intensified clonidine-induced reduction of blood pressure. This effect was achieved at muscimol doses which themselves had no influence on blood pressure. Muscimol injected after clonidine ...
Harris J - - 1993
In the decerebrated rabbit, intrathecal administration of the alpha 2-adrenoceptor antagonists idazoxan and yohimbine increases reflex responses of gastrocnemius motoneurones to electrical stimulation of the sural nerve. The maximum effect of idazoxan is about twice that of yohimbine, suggesting that part of the effect of idazoxan may be due to ...
Izumi Y - - 1993
The effects of clonidine, a potent alpha 2 adrenergic agonist and an imidazole/imidazoline receptor agonist, were examined in the cat cerebrovascular system, measuring cerebral oxygen and carbon dioxide tension (BrPo2, BrPco2) and arterial blood pressure. Intracarotid injection of clonidine (2 micrograms/kg) produced a gradual decrease in systemic blood pressure without ...
Pollock S H - - 1993
We have reported previously that phenyl-2-aminoethyl sulfide and its derivatives are excellent substrates for dopamine-beta-monooxygenase and produce an antihypertensive effect in spontaneously hypertensive rats after i.p. administration. In the studies reported herein, we demonstrate that alpha-methyl-phenyl-2-aminoethyl sulfide and 4-hydroxy-alpha-methyl-phenyl-2-aminoethyl sulfide, the methylated and hydroxymethylated derivatives of phenyl-2-aminoethyl sulfide, respectively, decrease ...
Yang C H CH Department of Anesthesiology, Chang Gung Memorial - - 1993
The effects of intravenous clonidine, a central adrenergic alpha-2 agonist, on the incidence of shivering and hemodynamic changes after epidural anesthesia were assessed in patients undergoing extracorporeal shock wave lithotripsy (ESWL). Forty ASA class I or II patients were randomly assigned in a double-blind manner to one of two groups. ...
Given M B - - 1993
In the conscious dog, intravenous administration of methionine-enkephalin produces simultaneous increases in both heart rate (HR) and mean arterial blood pressure (MAP). This report describes both depressor and cardioaccelerator responses to methionine-enkephalin (10 micrograms/kg IV) in conscious dogs following acute hypotension induced by either bolus injection of isoproterenol (0.1-5.0 micrograms/kg ...
Polarz H - - 1993
The objective of the study was to assess the effects of premedication with clonidine on intraocular pressure (IOP) after the administration of succinylcholine. Fifty elderly patients undergoing ophthalmic surgery were randomly allocated to two study groups. Group 1 patients (n = 25) received clonidine, 300 micrograms p.o. In group 2 ...
Lin J C - - 1993
In the present study, we evaluated the relationship between hypertension and the antinociceptive effect of clonidine in genetically hypertensive rats. Intraperitoneal (i.p.) administration of clonidine (0.69 mg/kg) produced hypoalgesia without lowering blood pressure in conscious spontaneously hypertensive (SH), spontaneously hypertensive-stroke prone (SH-SP) and Wistar-Kyoto (WKY) rats. The antinociceptive effect of ...
Madeddu P - - 1993
Cadmium, a trace element from natural and industrial sources, may contribute to the pathogenesis of arterial hypertension. We evaluated the effect induced by acute intracerebroventricular (icv) administration of cadmium on mean blood pressure of normotensive conscious rats. Intracerebroventricular cadmium (1 to 10 micrograms) produced a dose-dependent, sustained increase in mean ...
Courtice G P - - 1993
In this study, we investigated the cardiovascular effects of four tachykinins in the anaesthetized toad, Bufo marinus. The potencies were compared of the amphibian peptides ranakinin and physalaemin and the mammalian peptide substance P, all of which interact preferentially with tachykinin NK-1 receptors. Neurokinin B, which is found in both ...
Williams J S - - 1993
BACKGROUND: Intraspinal clonidine injection produces analgesia free of respiratory depression, but also decreases blood pressure and causes sedation. Spinal neostigmine injection alone increases blood pressure in animals and enhances clonidine-induced analgesia. METHODS: To test whether neostigmine would alter clonidine-induced hypotension, nine chronically prepared sheep received intrathecal injections of saline or ...
Eisenach J - - 1993
BACKGROUND: alpha 2-Adrenergic agonists such as clonidine produce behavioral analgesia and cardiovascular depression in animals, but clonidine's site of action in clinical analgesia and cerebrospinal fluid (CSF) pharmacokinetics have not been defined. METHODS: Clonidine was administered in the lumbar epidural space to nine volunteers while monitoring blood pressure, heart rate, ...
Abi-Jaoude F - - 1993
The purpose of this study was to assess the efficacy of clonidine in achieving perioperative hemodynamic stability in patients undergoing coronary artery bypass grafting performed under high-dose alfentanil anesthesia. Twenty-four patients with left ventricular ejection fraction greater than 0.5 were prospectively studied in a double-blind manner; those requiring emergency procedures ...
Lowenthal D T - - 1993
The efficacy of transdermally administered clonidine was evaluated in twenty-four patients with mild-to-moderate hypertension (seated diastolic blood pressure 95-115 mmHg) and renal impairment. Patients were initially treated with oral clonidine; the dose was titrated until the seated diastolic pressure fell below 90 mmHg or a minimum 10% reduction in baseline ...
Rosansky S J - - 1993
Large fluctuations of blood pressure are commonly experienced by hypertensive, chronic hemodialysis patients. Many patients hold anti-hypertensive medication immediately prior to dialysis to prevent intradialytic hypotension. Weekly dosing of continuously released antihypertensive agents may result in better blood pressure control than conventional daily dosing. To evaluate the effect of weekly ...
Kirby K C - - 1993
We examined the effect of morphine pretreatment spacing on intensity of subsequent precipitated withdrawal response to test the hypothesis that withdrawal intensity would be inversely related to pretreatment spacing. Subjects were ten nondependent male volunteers who reported using opioids an average of 2.5 times per week. Three IM morphine injections ...
Bremner P - - 1993
We have investigated the cardiovascular and metabolic effects of multiple inhaled doses of salbutamol and hexoprenaline in 12 healthy volunteers. They inhaled 200 micrograms of salbutamol or hexoprenaline at 15 min intervals for 60 min from a metered dose inhaler (total dose 1000 micrograms). We measured heart rate, blood pressure, ...
Martin G - - 1993
Eleven patients with moderate to severe hypertension were pre-treated with oral labetalol 800-1200 mg/day for one week, prior to receiving two i.v. infusions of dopamine 1-3 micrograms/kg/min each of 30 min each, before and after the i.v. bolus injection of metoclopramide 30 mg. There were washout periods before and after ...
Pettersson A - - 1993
Three gilts were each equipped with 2 ultra-miniature pressure sensors, placed at 2 different points along the same isthmus of the oviduct. Following base recordings of isthmic intraluminal pressure, the gilts were treated with 2.2 mg flunixin meglumine (FM) per kg body weight. After FM treatment, the peripheral plasma levels ...
Muzi M - - 1992
Clonidine, an alpha 2-adrenergic agonist, has been shown to modify the hemodynamic responses to surgery. To examine further the mechanism underlying this action, we evaluated the neurocirculatory effects of oral clonidine and the ability of clonidine to alter the hemodynamic and sympathetic responses to a noxious stimulus (cold pressor test) ...
Hong M - - 1992
The stereoselective central effects of a novel, highly potent and selective alpha 2-agonist medetomidine on adrenergic neuronal activity, reflected by changes in catechol oxidation current, in the rostral ventrolateral medulla of the halothane-anesthetized rat were examined using in vivo differential normal pulse voltammetry. Dexmedetomidine, the active isomer, significantly decreased catechol ...
Nielsen H - - 1992
Human subcutaneous resistance arteries (122-298 microns), isolated from 139 patients undergoing surgery, were mounted in an isometric myograph. With the use of multiple regression analysis, five different modes of activation were examined for possible associations with age and mean arterial blood pressure of the patients: the contractile responses to 10 ...
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