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Results 351 - 400 of 1009
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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 ...
Wiƛniewska 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 ...
Rockemann M G - - 1995
This study characterizes analgesia an hemodynamics after epidural clonidine 8 micrograms/kg (Group C) or clonidine 4 micrograms/kg+morphine 2 mg (Group CM) in comparison to epidural morphine 50 micrograms/kg (Group M). Forty-five patients scheduled for pancreatectomy in combined general/epidural anesthesia were studied. The study drugs were administered 75 min postoperatively and ...
Lin H C - - 1995
The haemodynamic effects of a combination of propranolol and clonidine were evaluated in 20 patients with post-hepatitic cirrhosis. Haemodynamic measurements were taken before and 30 min after an intravenous injection of 0.1 mg/kg of propranolol. Thereafter, each patient was given an oral dose of 150 micrograms of clonidine and re-measured ...
Devcic A - - 1995
This study explored the effectiveness of oral clonidine premedication in attenuating sympathetic activation, tachycardia, and hypertension triggered by desflurane. After institutional review board approval, informed consent was obtained from 15 young, healthy male volunteers. Heart rate (HR, electrocardiogram), mean arterial pressure (MAP, radial artery catheter), and central venous pressure (CVP, ...
Asgeirsson B - - 1995
Therapy of post-traumatic brain oedema often includes preservation of high arterial blood pressure to avoid secondary ischaemic injuries to the brain. This practice can be questioned since high arterial blood pressure may aggravate brain oedema through raised hydrostatic capillary pressure, causing fluid filtration across the damaged blood-brain barrier. This latter ...
Szabo B - - 1995
Agmatine has been identified as a "clonidine-displacing substance" in extracts from bovine brain. We studied its effect on cardiovascular regulation and the role played in this effect by alpha 2-adrenoceptors. In conscious rabbits, agmatine 10 micrograms kg-1 injected intracisternally (i.c.) caused no change, whereas agmatine 30, 100 and 300 micrograms ...
Lines C - - 1995
1. Two studies were undertaken to develop a model of experimentally induced anxiety in normal volunteers based on cholecystokinin (CCK) receptor agonism/antagonism. 2. In Study 1 rapid intravenous injections of the CCK receptor subtype B (CCKB) agonist pentagastrin (0.15, 0.3 and 0.6 micrograms kg-1) were found to produce dose-related increases ...
Howell R E - - 1995
1. In order to determine an involvement of muscarinic M2 receptors in the regulation of systemic arterial blood pressure, we investigated the cardiovascular effects of the M2-selective antagonist methoctramine and other agents in anaesthetized guinea-pigs. 2. Intravenous injection of methoctramine, atropine, pirenzepine (an M1-selective muscarinic antagonist) or 4-DAMP (an M3-selective ...
Inomata S - - 1995
Clonidine, an alpha 2-adrenergic agonist, augments the pressor response to intravenous ephedrine. If this effect is partly due to clonidine-induced potentiation of alpha 1-adrenoceptor-mediated vasoconstriction, it is also assumed that clonidine would enhance the pressor effect of phenylephrine as an alpha 1-adrenergic agonist. The authors studied haemodynamic responses to intravenous ...
Kölbel F - - 1995
The existence of endogenous ligands of opioid receptors prompted research of a potential endogenous digitalis-like factor (DLF) and of endogenous clonidine-displacing substance (CDS). Within eleven years of research, endogenous ouabaine was identified as DLF. It originates in the adrenal cortex. Its physiological role is not yet clear. Most probably, endogenous ...
Vargas H M - - 1995
Alpha 1 (alpha 1)-adrenoceptors can be found at numerous end organs in the autonomic nervous system, especially vascular smooth muscle. The tonic sympathetic activation of vascular alpha 1-adrenoceptors maintains vascular resistance and is vital to the regulation of arterial pressure. Recent evidence clearly demonstrates that alpha 1-adrenoceptors are a heterogenous ...
Sun M K - - 1995
We investigated the cardiovascular responses in anesthetized ventilated rats to agmatine (decarboxylated arginine), an amine which is an endogenous clonidine-displacing substance (CDS) synthesized in brain. Intracisternal agmatine dose-dependently increased sympathetic nerve activity and arterial pressure (at 400 nmol by 8.7 +/- 2.1 microV and 28.6 +/- 2.7 mmHg, respectively) and ...
Wyse D G - - 1995
This cross-sectional study examined responses of the isolated cystic artery to 3 alpha-adrenoceptor agonists and the effects of 2 antagonists in relation to subjects' blood pressures. Potency of the 3 amines studied was: alpha-methylnorepinephrine > norepinephrine > phenylephrine. Responses to clonidine were trivial (< 5% of maximum) and remained < ...
Richter R M - - 1995
Three assays have been used to show that the neuropeptides human corticotropin-releasing factor (hCRF) and the ovine analogue oCRF produced substantial dose-dependent cardiovascular responses. The assays included intracerebroventricular (ICV) and intravenous (IV) administration in conscious rats, and also in vitro experiments with resistance arteries. Central administration of the peptides (0.1-10 ...
Fantaskey A - - 1995
Venlafaxine hydrochloride is a novel bicyclic antidepressant which inhibits the reuptake of serotonin, norepinephrine and, to a lesser extent, dopamine. A 41-year-old female ingested 4.5 g venlafaxine, 500 mg diphenhydramine, 50 mg thiothixene and subsequently experienced severe central nervous system depression requiring intubation. She also developed elevated systolic and diastolic ...
Sun X - - 1994
The modulatory effects of alpha-trinositol (D-myo-inositol-1.2.6- trisphosphate; PP 56) on the systemic arterial blood pressor responses induced by neuropeptide Y, preganglionic nerve stimulation, phenylephrine and vasopressin were studied in pithed rats. Intravenous administration (within 2 min.) of alpha-trinositol reduced the neuropeptide Y-induced increase in mean arterial pressure within a defined ...
Bernard J M - - 1994
Agonist interactions in antinociceptive effects between clonidine and opioids can be used to reduce opioid requirements in surgical patients. However, clonidine can cause marked sedation and associated respiratory dysfunction. Thus, the benefit of using clonidine to reduce opioid use on respiration is questionable. This double-blind randomized study compared the analgesic ...
Abdel-Rahman A A - - 1994
This study tested the hypothesis that concurrent ethanol administration attenuates the hypotensive effect of clonidine. Four groups of spontaneously hypertensive rats matched for baseline systolic pressure and body weight were randomly assigned the following treatments: (1) water (control), (2) ethanol, (3) clonidine, and (4) ethanol plus clonidine for 13 weeks. ...
Cheskin L J - - 1994
We compared the short-term efficacy of a high-dose, 3 day regimen of buprenorphine to a standard 5-day course of clonidine in attenuating the signs and symptoms of the acute opioid abstinence syndrome during rapid detoxification from heroin in 25 men and women admitted to a closed inpatient research ward for ...
Wocial B - - 1994
Neuropeptide Y (NPY) is a vasoconstrictor sympathetic cotransmitter and a modulator of adrenergic function whose role in hypertension is yet unknown. We studied the co-release of NPY and noradrenaline (NA) in patients with essential hypertension (13 females, 11 males, age 42 +/- 13 years) by measuring plasma levels of NPY-immunoreactivity ...
Fischetti F - - 1994
Clonidine, an imidazoline derivative, is a widely used antihypertensive agent which acts by stimulating the alpha 2-adrenergic receptors at the central nervous system. Clonidine also seems to exert beneficial effects on baroreceptor reflex sensitivity which is usually altered by arterial systemic hypertension and arteriosclerosis. Aim of the study was to ...
Di Francesco G F - - 1994
The cardiovascular effects of the 5-HT1A receptor agonists MDL 73,975 (8-[2-(2,3-dihydro-8-methoxy-1,4-benzodoxin-2-yl)methylaminol++ +]-ethyl]-8- azaspiro[4,5]decane-7,9-dione hydrochloride) and flesinoxan (10-300 micrograms/kg subcutaneously, s.c.), the 5-HT1A receptor antagonist NAN 190 (2-[4-[4-(2-methoxyphenyl)-1-piperazinyl]butyl]-1H-isoindole-1,3(2H)- dione,1,2-ethanedioate), and the alpha 1-adrenoceptor antagonist prazosin have been investigated in conscious normotensive and renal hypertensive dogs. In normotensive dogs the increases in ...
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