Prolonged Reduction (prolonged + reduction)

Distribution by Scientific Domains


Selected Abstracts


Tissue distribution of antihypertensive dipeptide, Val-Tyr, after its single oral administration to spontaneously hypertensive rats

JOURNAL OF PEPTIDE SCIENCE, Issue 9 2004
Toshiro Matsui
Abstract The distribution of an antihypertensive dipeptide, Val-Tyr (VY), in the tissues of spontaneously hypertensive rats (SHR) was investigated in this study. A single oral administration of VY (10 mg/kg) to 18-week-old SHR resulted in a prolonged reduction of systolic blood pressure (SBP) up to 9 h (SBP0h198.0 3.6 mmHg; SBP9h 154.6 3.5 mmHg). As a result of VY determination, a roughly 10-fold higher increment of plasma VY level was observed at 1 h than that at 0 h, whereas thereafter the level declined rapidly. In tissues, VY was widely accumulated in the kidney, lung, heart, mesenteric artery and abdominal aorta with the area under the curve over 9 h of more than 40 pmol h/g tissue; of these a higher VY level was observed in the kidney and lung. In addition, a mean resident time (MRT) for each tissue (>5 h except for liver) revealed that VY preferably accumulated in the tissues rather than in the plasma (MRT 3.8 h). Significant reductions of tissue angiotensin I-converting enzyme activity and angiotensin II level were found in the abdominal aorta as well as in the kidney, suggesting that these organs could be a target site associated with the antihypertensive action of VY. Copyright 2004 European Peptide Society and John Wiley & Sons, Ltd. [source]


Effect of adrenergic stimulation on cutaneous microcirculation immediately after surgical adventitiectomy in a rat skin flap model

MICROSURGERY, Issue 6 2008
Jean-Pierre H. Lecoq M.D.
Chronic sympathetic denervation leads to the development of supersentivity to adrenergic agents. Free flap surgery results in the disruption of the autonomic nerve fibers running along the anastomosed vessels. We therefore investigated the early effect of surgical sympathectomy on the reactivity of cutaneous microcirculation challenged to adrenergic agents. Two epigastric flaps were elevated and exposed in 15 rats. On the right flap (Side A), a circular adventitiectomy of the feeder vessels was realized to provide surgical sympathectomy. On the left flap (Side N), vessels were kept intact. The following drugs were then given intravenously successively: phenylephrine (10 and 15 ,g kg,1), norepinephrine (10 ,g kg,1), prazocin (1 mg kg,1) followed by norepinephrine (10 ,g kg,1). Cutaneous microcirculation was assessed using Laser-Doppler Flowmeters simultaneously on the two flaps after each drug administration. Mean arterial pressure was also measured. On side N, phenylephrine and norepinephrine resulted in a transient increase in cutaneous microcirculation followed by a more prolonged reduction. On side A, only the initial increase was observed, which was greater and longer as compared with side N, and paralleled the increase in mean arterial pressure. After prazocin pre-treatment, norepinephrine produced a transient increase in cutaneous microcirculation similar on both sides, and parallel to the changes in arterial pressure. No decrease in cutaneous microcirculation was observed. Immediately after surgical adventitiectomy, the vasoconstriction produced by ,-adrenergic agents is prevented. No denervation-induced hypersentivity is observed. Surgical sympathectomy might protect cutaneous flaps from vasoconstriction induced by endogenous catecholamines release. 2008 Wiley-Liss, Inc. Microsurgery, 2008. [source]


Effect of ketamine anesthesia on daily food intake in Macaca mulatta and Cercopithecus aethiops,

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2007
Danielle A. Springer
Abstract Ketamine hydrochloride is frequently administered to non-human primates as a means of chemical restraint. This procedure can be a frequent source of stress to monkeys at research facilities, impacting animal health, well-being and research quality. This study was designed to measure ketamine's effect on daily food intake, a parameter that reflects and influences animal well-being and directly impacts research studies. On five occasions, baseline daily food intake was compared to daily food intake occurring 24, 48, 72, 96, and 120,h after an intramuscular injection of 10,mg/kg ketamine in male African green monkeys (AGMs) (Cercopithecus aethiops) and male and female rhesus macaques (Macaca mulatta). AGMs and female rhesus macaques had significantly reduced daily food intake during the first 4 days after receiving ketamine. The AGMs continued to display significantly reduced daily food intake on the fifth day after ketamine. The male rhesus macagues showed a trend toward reduced daily food intake, greatest during the first 2 days and remaining less than baseline intake through the fifth day following ketamine. The degree of observed food intake reduction was most severe at the 24,h (mean percent intake reduction: AGMs: 57%; rhesus males: 48%; rhesus females: 40%) and 48,h time points (AGMs: 24%; rhesus males: 14%; rhesus females: 13%). A subset of the AGMs that did not receive ketamine, but observed other animals in the room receive ketamine, showed reduced food intake at 24 and 48,h after ketamine, though not to the degree associated with ketamine administration. These results indicate that ketamine anesthesia is associated with a prolonged reduction in daily food intake in AGMs and rhesus macaques. Frequent use of ketamine in non-human primates may have a significant impact on animal health and well-being, and alternatives to its use warrant consideration. Am. J. Primatol. 69:1080,1092, 2007. Published 2007 Wiley-Liss, Inc. [source]


Comparison of the cardio-respiratory effects of methadone and morphine in conscious dogs,

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2009
A. A. MAIANTE
The effects of methadone and morphine were compared in conscious dogs. Six animals received morphine sulfate (1 mg/kg) or methadone hydrochloride (0.5 mg/kg [MET0.5] or 1.0 mg/kg [MET1.0]) intravenously (i.v.) in a randomized complete block design. Cardiopulmonary variables were recorded before (baseline), and for 120 min after drug administration. One outlier was not included in the statistical analysis for hemodynamic data. Morphine decreased heart rate (HR) compared to baseline from 30 to 120 min (,15% to ,26%), while cardiac index (CI) was reduced only at 120 min (,19%). Greater and more prolonged reductions in HR (,32% to ,46%) and in CI (,24% to ,52%) were observed after MET1.0, while intermediate reductions were recorded after MET0.5 (,19 to ,28% for HR and ,17% to ,27% for CI). The systemic vascular resistance index (SVRI) was increased after methadone; MET1.0 produced higher SVRI values than MET0.5 (maximum increases: 57% and 165% for MET0.5 and MET1.0, respectively). Compared to morphine, oxygen partial pressure (PaO2) was lower (,12% to ,13%) at 5 min of methadone (0.5 and 1.0 mg/kg), while carbon dioxide partial pressure (PaCO2) did not change significantly. It was concluded that methadone induces cardiovascular changes that are dose-related and is a more potent cardiovascular depressant agent than morphine in conscious dogs. [source]