Search Results
Results 301 - 350 of 980
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Khayyal M T - - 1998
Hypercholesterolemia is known to affect the responsiveness of various blood vessels to endogenous and to exogenous vasoactive agents. Of particular interest is the increased responsiveness to vasoconstrictors, e.g., 5-hydroxy tryptamine and noradrenaline, and the decreased reactivity towards vasodilators, e.g., acetylcholine. This, together with the development of arteriosclerosis, could play an ...
Lim D Y - - 1998
This study was designed to investigate the effect of endothelin-1 (ET-1) on clonidine-induced cardiovascular effects in urethane-anesthetized rabbits and to clarify the mechanism of its action. Clonidine (5, 10, and 20 micrograms/kg) given into a femoral vein (i.v.) produced a marked dose-dependent fall in arterial blood pressure and heart rate, ...
Champion H C - - 1998
The endogenous peptides endomorphin 1 and 2 are newly isolated, potent, selective mu-opioid receptor agonists. In the present study, responses to the endomorphin peptides were investigated in the systemic vascular bed of the cat. Endomorphin 1 and 2 induced dose-related biphasic changes in systemic arterial pressure when injected in doses ...
Yamaguchi S - - 1997
Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 micrograms/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and ...
Bharucha A E - - 1997
Our aims were to assess the role of adrenergic modulation in the hyperventilation-induced increase in colonic tone. Of 40 healthy volunteers, 12 received placebo (saline) and the remaining 28 received either clonidine, yohimbine, phenylephrine, or ritodrine. Time-frequency mapping of heart rate based on Wigner distribution assessed variations in parasympathetic and ...
Del Bo A - - 1997
BACKGROUND: Changes in plasma osmolality and arterial pressure can affect the secretion of vasopressin (AVP). OBJECTIVE: To investigate the effect of a drug-induced lowering of the arterial pressure on the plasma concentration of AVP and on its osmoregulation in moderately severe uncomplicated hypertensives. DESIGN AND METHODS: A group of 33 ...
Iriuchijima J - - 1997
The original aim of this study was to observe whether the depressor drug clonidine inhibited the abnormal hindquarter tone in spontaneously hypertensive rats (SHR). In conscious SHR and normotensive control rats (NCR), hindquarter (terminal aortic) blood flow was observed with an implanted electromagnetic flow probe and mean arterial pressure with ...
Gregorakos L - - 1997
OBJECTIVE: To evaluate the effectiveness of clonidine in the management of unstable blood pressure in severe tetanus. DESIGN: Patients with severe tetanus and blood pressure instability were treated with clonidine and the results were compared with those of other patients with severe tetanus who were not treated with clonidine. SETTING: ...
El-Mas M M - - 1997
Our previous studies have shown that ethanol selectively counteracts centrally mediated hypotensive responses. This study investigated the role of cardiac output and peripheral resistance in the antagonistic interaction between ethanol and antihypertensive drugs. Changes in blood pressure, heart rate, cardiac index, stroke volume, and peripheral resistance elicited by clonidine and ...
You-hua Z - - 1997
In this double-blind, placebo-controlled crossover study, we examined the effect of transdermal clonidine (given for 5 days) on autonomic control in 14 patients with mild to moderate congestive heart failure by heart rate variability analysis. Compared with placebo, clonidine increased the 24-h mean R-R interval from 718+/-110 to 811+/-117 ms ...
Taittonen M T - - 1997
Premedication has been shown to affect both oxygen consumption and metabolic rate. We have compared the perioperative metabolic and haemodynamic effects of two alpha 2-agonists, clonidine and the more selective dexmedetomidine, in 30 ASA I patients undergoing plastic surgical procedures under general anaesthesia. Patients were premedicated with clonidine 4 micrograms ...
Schmidt M E - - 1997
Seven male and five female volunteers underwent double-blind infusions of the alpha 2-adrenoceptor antagonist idazoxan (100 and 200 micrograms/mg) and placebo in random order. Blood pressure, plasma norepinephrine, growth hormone and subjective responses were measured. The higher dose of idazoxan produced increases in blood pressure, norepinephrine and growth hormone and ...
Bealer S L - - 1997
The roles of alpha-adrenoceptors in the anteroventral third ventricle (AV3V) and diagonal band of Broca (DBB) in cardiovascular responses to peripheral hypertonicity were investigated in conscious rats. Normal artificial cerebrospinal fluid (aCSF) or aCSF containing phentolamine (alpha1- and alpha2-antagonist), yohimbine (alpha2-antagonist), or prazosin (alpha1-antagonist) was perfused through microdialysis probes in ...
De Negri P - - 1997
BACKGROUND: Clonidine, an alpha 2 agonist, is known to prolong the action of local anesthetics, and to provide a satisfactory analgesia; hypotension and bradycardia have been observed after its intrathecal administration. The aim of our study was to determine whether intrathecal administration of clonidine can reduce the dose of local ...
Rubio G - - 1997
Blood pressure and heart rate were monitored in heroin addicts detoxified with guanfacine in an outpatient program. Retrospective analysis of the cardiovascular parameters from the addicts who failed this detoxification during the first 5 days of treatment (they consumed heroin within this period) showed that these patients experienced less hypotension ...
Jonsson M - - 1997
We have studied the role of neutrophils and the effects of the chemotactic factor FMLP, using normal, neutropenic (after cyclophosphamide treatment) and C5a desArg-treated unanesthetized rabbits. The intravenous administration of FMLP in normal animals induces transient and dose-dependent hypotension, neutropenia and thrombocytopenia, with a maximal response in 3 minutes. When ...
Taittonen M - - 1997
In this double-blind placebo controlled study the preoperative cardiovascular and metabolic effects of intramuscular (i.m.) clonidine and midazolam are assessed. Forty-five ASA Grade I patients (n = 15 per group) undergoing plastic surgical procedures were randomly allocated to receive either placebo, clonidine 4 micrograms kg-1 or midazolam 70 micrograms kg-1. ...
Bergendahl H T - - 1997
The beneficial perioperative effects of the alpha-2 agonist clonidine have recently been verified in paediatric patients, and the pharmacokinetics have been found to be similar to what has been reported in adults. In a previous study we found that 2.5 micrograms/kg of clonidine causes a significant reduction in blood pressure. ...
ter Minassian A - - 1997
alpha 2-Adrenergic agonists induce cerebral vasoconstriction, reduce intracranial pressure (ICP) in experimental animals and may be useful in the hemodynamic management of head-injured patients. We studied the effects of the alpha 2 agonist clonidine on the cerebral circulation in 12 head-injured patients (Glasgow Coma Scale score < 8). Middle cerebral ...
Prichard B N - - 1997
Imidazoline I1-receptor agonism represents a new mode of antihypertensive action to inhibit peripheral alpha-adrenergic tone by a central mechanism. Adrenaline, noradrenaline and renin levels are reduced, a finding consistent with central inhibition of sympathetic tone. Acute haemodynamic studies indicate that moxonidine results in an acute decrease in blood pressure due ...
Taniguchi N - - 1996
The effects of NS-49 ((R)-(-)-3'-(2-amino-1-hydroxyethyl)-4'-fluoromethane sulfonanilide hydrochloride), an alpha 1A-adrenoceptor-selective agonist, on intraurethral pressure and blood pressure were investigated in anesthetized dogs. In addition, the contractile effects of NS-49 on the isolated dog urethra and carotid artery were compared with those of non-selective alpha 1-adrenoceptor agonists. Intravenously (i.v.) administered NS-49 ...
Brune M E - - 1996
In this study, we used a novel conscious dog model to evaluate the uroselectivity of selected alpha 1-antagonists either approved for human use or in clinical development for the treatment of symptomatic benign prostatic hyperplasia (BPH) and compared those results to their in vitro binding and functional affinities at alpha ...
Mjahed K - - 1996
BACKGROUND AND OBJECTIVES: Clonidine, an alpha-2-adrenoreceptor agonist, has been shown to decrease intraocular pressure (IOP) and to have some analgesic and sedative effects when it is used in premedication for ophthalmic surgery. This study was designed to investigate the efficacy of lidocaine-clonidine retrobulbar block for cataract surgery with respect to ...
Nagasaka H - - 1996
BACKGROUND: Three types of opioid receptors, mu, delta, and kappa, are present in the periphery and in the central nervous system. In contrast to the effects in the central nervous system, the antinociceptive action of opioids in the periphery is not as well characterized. The effects of intraarticular, spinal, and ...
Russ H - - 1996
1,1'-Diethyl-2,2'-cyanine (decynium22) and 1,1'-diisopropyl-2,4'-cyanine (disprocynium24) are highly potent inhibitors of the extraneuronal monamine transporter. When given as i.v. bolus injections (4 mumol kg-1) to anaesthetized rabbits, both drugs elicited a transient fall in blood pressure without altering heart rate. The observed maximum fall in diastolic blood pressure was 59% after ...
Sudoh K - - 1996
1. The effect of tamsulosin (YM617, (R) (-)-S-[2-[[2-(o-ethoxyphenoxy)ethyl]amino] propyl]-2-methoxybenzenesulfonamide HCl), a potent and selective alpha 1-adrenoceptor antagonist, was examined on urethral pressure profile (UPP) and mean arterial blood pressure (MBP) in pentobarbital anaesthetized male dogs. 2. Selective alpha 1-adrenoceptor antagonists tamsulosin (1-100 micrograms kg-1 i.v.), prazosin (1-100 micrograms kg-1 i.v.) ...
Rupp H - - 1996
To examine the antihypertensive action of the centrally acting antiadrenergic drugs moxonidine and clonidine, systolic and diastolic blood pressure as well as heart rate were monitored by radio telemetry in spontaneously hypertensive rats (SHR) with established high blood pressure. Increasing doses were administered with regular rat chow for 6-8 day ...
Bremner J D - - 1996
Studies in animals have shown a relationship between alterations in noradrenergic brain system function and behaviors of anxiety and fear. These findings have generated the hypothesis that the symptoms seen in patients with anxiety disorders may be related to alterations in noradrenergic function. A number of clinical studies have tested ...
Kroin J S - - 1996
Intrathecal delivery of alpha(2)-adrenergic agonists produces an analgesic effect. However, hemodynamic side effects limit their clinical usage. To more fully characterize the effects on heart rate and arterial blood pressure of alpha(2)-adrenergic agonists, clonidine and tizanidine were injected intrathecally in conscious dogs. Both compounds produced a potent inhibition of thermal ...
Nomura S - - 1996
Effects of clonidine on the elevated arterial diastolic blood pressure induced by infusion of alpha 1-adrenoceptor agonists were studied in pithed rats. Intravenous injection of clonidine resulted in a dose-dependent pressor response at a resting state and a further increase in the moderately elevated diastolic blood pressure induced by infusion ...
Montastruc J L - - 1996
1. The present study was designed to investigate tolerance to several pharmacological effects of apomorphine. 2. Changes in blood pressure, heart rate, plasma noradrenaline levels, rectal temperature, respiratory rate and retching plus vomiting were compared after administration of apomorphine (200 micrograms kg-1, i.v. as a bolus) or saline at different ...
Nishikawa T - - 1996
BACKGROUND: Hypoxia or hypercapnia elicits cardiovascular responses associated with increased plasma catecholamine concentrations, whereas clonidine, an alpha(2)- adrenergic agonist, decreases plasma catecholamine concentrations. The authors examined whether systemic clonidine administration would alter the hemodynamic and catecholamine responses to hypoxia or hypercapnia in anesthetized dogs. METHODS: Pentobarbital-anesthetized dogs whose lungs were ...
Tanaka M - - 1996
We studied pressor responses and changes in plasma catecholamine concentrations following two consecutive doses of ephedrine 0.1 mg.kg-1 with (n = 20) and without (n = 20) clonidine 5 micrograms.kg-1 premedication in patients presenting for a variety of major surgical procedures under general anaesthesia. Arterial blood pressure and heart rate ...
Boucher M - - 1996
1. The cardiac chronotropic effects of rilmenidine (10-100 micrograms kg-1) and clonidine (1-10 micrograms kg-1) were studied in conscious dogs with chronic atrioventricular block. 2. Rilmenidine and clonidine initially (< 3 min) decreased atrial rate, although the effect was not related to dose. More lastingly, ventricular rate was decreased in ...
Alibhai H I - - 1996
Medetomidine and xylazine are alpha 2 adrenoceptor agonists which are used as sedatives and premedicants in small animals. However, bradycardia is a side effect and the use of atropine sulphate has been recommended to counteract it. This study investigated the effects of combining medetomidine (40 micrograms/kg) and atropine (30 micrograms/kg) ...
Kreutz R - - 1996
The purpose of this study was to evaluate the effects of short-term sympathetic inhibition with clonidine on blood pressure and renal responses to central hypervolaemia induced by thermoneutral head-out water immersion. Eleven healthy subjects were randomly studied on two occasions, during a 1 h pre-immersion period, 2 h of water ...
Muruve N - - 1996
PURPOSE: The effectiveness and complications of intracorporeal phenylephrine without aspiration or irrigation as a treatment for priapism were assessed. MATERIALS AND METHODS: Nine consecutive patients who presented with priapism were treated with 0.5 mg. phenylephrine diluted in 2 cc normal saline injected directly into the corpus cavernosum. Blood pressure and ...
Wiśniewska R - - 1996
The influence of pentagastrin (PG) and its analogues: 3-leupentagastrin (3-leu-PG), 4-AspOBzl-pentagastrin (4-AspOBzl-PG), and of the cholecystokinin -terminal tetrapeptide (CCK-4) and its analogue CCK-4(Phet) on rat arterial blood pressure and isolated heart were studied. 4-AspOBzl-PG and CCK-4 (Phet) had no effect on the arterial blood pressure or the isolated heart. PG ...
Prichard B N - - 1996
Stimulation of the imidazoline I1-receptor represents a new mode of antihypertensive action, inhibiting peripheral alpha-adrenergic tone by a central mechanism. Moxonidine is an imidazoline I1-receptor modulator. Acute hemodynamic studies indicate that moxonidine results in an acute fall of both blood pressure and systemic vascular resistance, whereas heart rate, cardiac output, ...
van Damme R - - 1996
We compared the behavior of two subspecies ofPodarcis hispanica lizards in cages that had been chemically marked by a saurophagous snake, the viperVipera latastei. One of the subspecies (P.h. atrata) has experienced a relaxation from predation pressure by this viper, as snakes were eradicated from the island it inhabits over ...
Darkwa F K - - 1995
Indometacin pretreatment potentiates the natriuretic action of the mixed alpha 2-adrenoceptor/imidazoline receptor agonist clonidine. In the present study we determined the effects of indometacin pretreatment on natriuretic actions of the selective I1 imidazoline receptor agonist. In anaesthetized rats, an intrarenal infusion of moxonidine (0, 0.3, 1, and 3 nmol/kg/min) increased ...
Jacobs M C - - 1995
OBJECTIVE: Doxazosin, a selective alpha1-adrenoceptor antagonist, lowers blood pressure by reducing peripheral vascular resistance without causing reflex tachycardia. To discover whether antihypertensive treatment with an alpha1-adrenoceptor blocker is accompanied by an increase in sympathoadrenomedullary activity, we studied plasma catecholamine kinetics before and during treatment with doxazosin. PATIENTS AND METHODS: Eleven ...
Rosen M I - - 1995
To determine the reliability of serial naloxone challenges, five heroin addicts stabilized on methadone were given 0.2 mg naloxone intravenously on three consecutive days. Two-factor ANOVA revealed that the between-subjects effect accounted for at least 63% of the variance in each of the dependent measures, and the effect of challenge ...
Manolis A J - - 1995
Neurohormonal activation with increased plasma renin activity and norepinephrine and vasopressin levels is characteristic of congestive heart failure and contributes to further decompensation and poor prognosis. We treated 20 such patients with the centrally acting sympathoinhibitory drug clonidine 0.15 mg BID and obtained hemodynamic measurements by cardiac catheterization and plasma ...
Tanaka M - - 1995
It has been suggested that postjunctional alpha 1-adrenoceptor mediated vasoconstriction is enhanced by clonidine. We have examined in humans if the pressor responses to noradrenaline and phenylephrine are enhanced by clonidine premedication. Seventy-seven patients were allocated randomly to either clonidine (n = 38) or control (n = 39) groups. Patients ...
De Kock M - - 1995
STUDY OBJECTIVE: Determine the hemodynamic consequences of intraoperative clonidine during major abdominal surgery. DESIGN: Prospective open trial. SETTING: Teaching hospital. PATIENTS: 402 consecutive patients scheduled for major abdominal surgery. INTERVENTIONS: 350 consecutive patients received intravenous (IV) clonidine (loading dose of 4 micrograms/kg in 20 minutes at anesthesia induction, followed by ...
Reid J L - - 1995
Centrally acting antihypertensive drugs are recognized to be safe and effective treatment for high blood pressure. Centrally mediated side effects, such as sedation, are commonly dose- and treatment-limiting events. Imidazoline-preferring receptors, while functionally similar to alpha 2 adrenoceptors, are distinguishable not only on the basis of in vitro radioligand binding ...
Meehan W P - - 1995
Male Long-Evans rats were implanted with blood pressure transmitters and introduced as intruders for 60 min into the home cage of a reproductively active resident male rat. Physical interaction ended after 3-5 min when the intruder displayed clear submissive behaviors. A protective wire cage was placed over the intruder until ...
Bealer S L - - 1995
The role of adrenoreceptor stimulation and the peripheral mechanism mediating the increase in mean arterial blood pressure (MAP) and heart rate (HR) during administration of histamine (HA) in the paraventricular nucleus/anterior hypothalamus (PVN/AH) was evaluated in conscious rats. HA administered through microdialysis probes in the PVN/AH region increased MAP (18 ...
Bodmer C W - - 1995
BACKGROUND: Quinagolide (CV 205 502) is a dopamine D2-receptor agonist which has proved effective in the treatment of prolactinomas, reducing both serum PRL and tumour size. Some of its D2-receptor effects are mediated via alpha-adrenoceptors, which have a major influence on the control of vascular tone. The aim of this ...
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