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The influence of aminergic pathways on basal and stimulated vasopressin (AVP) release was studied in conscious rats, the stimulus for hormone release being an intracerebroventricular (ICV) injection of 5 µl 0.85M sodium chloride. The animals were treated with either phenoxybenzamine, propranolol or haloperidol prior to administration of the central hypertonic stimulus. Phenoxybenzamine elevated basal...
Substance P (SP) infused into the third cerebral ventricle blocks spontaneous ovulation in female rats, probably through catecholaminergic neurons. The studies presented in this paper were undertaken to investigate whether SP exerts its suppressing effect on ovulation in 6-hydroxydopamine (6-OHDA) pretreated female rats. After 8-12 days following 6-OHDA pretreatment female rats were infused, on the...
The ability of various peptides cleaved by plasmin from human fibrinogen and fibronectin or fibrinogen- and fibronectin- related synthetic peptides to induce histamine release from mast cells and collagenase and elastase from PMN- leukocytes was examined. Low molecular weight fibrinogen degradation products showed dose dependent secretion of collagenase. These peptides (mol. wt. 1.4 kD) at the concentration...
It is clear that all mucosal defensive mechanisms acting against aggressive ulcerogenic factors depend on adequate blood flow. When defence is active, ulcers tend to heal and do so faster when luminal aggression is prevented by reduction of acidity or eradication of H. pylori. Such successful treatment is so profitable that pharmaceutical companies invest vast fortunes on research into every aspect...
Mucus glycoproteins (mucins), the principal determinants of mucus protective qualities and mucosal defense, are studied extensively to define pathological aberrations in the relation to gastrointestinal disease and to develop the mucous barrier strengthening agents. Recent work from our laboratory provided evidence as to the initial stages of the gastrointestinal mucin synthesis, molecular size of...
In this work we compared in rats the influence of heptapeptide 1-7-angiotensin II, hexapeptide 2-7-angiotensin II, pentapeptide 3-7-angiotensin II and angiotensin II on motility, stereotypy, learning of conditioned avoidance responses and recall of passive avoidance behaviour allowing to avoid aversive stimulation. The 4 peptides administered 15 min before the experiment, tended to increase the number...
Adenosine deaminase (ADA) activity was estimated in mucosal specimens obtained endoscopically from the duodenal bulb. Three groups of subjects were studied: 1. 9 patients with achlorhydria, 2. 12 subjects with normal gastric acid secretion, 3. 5 patients with hypersecretion. Enzyme activity was measured by determination of ammonia liberated from the substrate according to the Chaney and Marbach method...
The effect of CCK-8 (50 ng, i. c. v.) on the neurohypophysial vasopressin and oxytocin storage was estimated in haemorrhaged (1 ml per 100 g b. w.) male Wistar rats. In another experimental series rats dehydrated for three days were given CCK-8 in a daily i. c. v. dose of 50 ng. The neurohypophysial vasopressin and oxytocin content was bioassayed by pressor effect following Dekański or milk- ejection...
This study was designed to assess the gastric secretory effects of ebrotidine, a novel H₂ receptor antagonist, in humans. Three groups (A, В and C) of male subjects with normal gastric mucosa were used. Group A (6 subjects) was used to determine the dose-dependency of gastric inhibitory effect of ebrotidine on basal and pentagastrin- induced maximal acid output. Group В (8 subjects) was employed to...
The purpose of the present study was to examine the effect of cycloheximide (Cx) - inhibitor of protein synthesis, on the development of pyrogenic tolerance to LPS. It has been observed that Cx at a dose of 1 mg/kg given intravenously 1 h prior to LPS did not prevent fever response, however it modified the induction of pyrogenic tolerance. It was manifested in existence of the second phase of fever...
The experiment was performed on Sprague-Dawley male rats weighing 203, 103 and 53 g, and female 99 g. Animals were fed for 2 weeks a diet containing 0,1 and 2,0 ppm of Se (Na₂ SeO₃ added). It was observed that the daily Se intake per kg of BW is lowered with an increase in animals body weight. Se-supplementation caused a significant increase of Se content in plasma and red blood cells. The highest...
The mediation of phospholipid secretion in rat sublingual salivary gland cells maintained in the presence of [³H]choline was investigated. The secretion of [³ H]choline-containing phospholipids was enhanced by β-adrenergic agonist, isoproterenol, to a greater extent than the cholinergic agoinst carbachol. A 2.9-fold increase in phospholipid secretion occurred with isoproterenol, while carbachol evoked...
The endothelial cells which line the blood vessels as a monolayer exert a remarkable control over the vascular system. Indeed, the endothelium can be regarded as a highly active metabolic and endocrine organ in its own right. On the hand, vasoactive substances such as serotonin and bradykinin are inactivated and on the other the cells can enzymatically produce the vasoconstrictor, angiotensin II and...
Pancreatic secretion in rats is regulated by feedback inhibition of cholecystokinin (CCK) release by proteases in the gut lumen, but little is known about the role of gastric acid in this regulation. This study, carried out on conscious rats with large gastric fistulas (GF) and pancreatic fistulas, shows that diversion of pancreatic juice results in the progressive stimulation of pancreatic secretion...
Adenosine deaminase activity was shown to decrease in each skeletal muscle type (the slow-twitch oxydative, fast-twitch oxydative - glycolytic and fast-twitch glycolytic) at the beginning of exercise of moderate intensity and to return to the control when exercise was continued till exhaustion. 5 min occlusion of the femoral artery had no effect on the enzyme activity in either muscle. The reduction...
Several studies have reported an extensive regional heterogeneity in myocardial blood flow. The reported coefficients of variation for regional myocardial perfusion range from about 0.2 to 0.4 in normotensive animals. The spatial distribution of myocardial perfusion during haemorrhagic hypotension seems not to have been assessed. The goal of the present study was to determine the regional heterogeneity...
Substance P (SP) is present in large quantities in the brainstem and hypophysiotropic areas of the brain, but its roles in gonadotropin and prolactin secretion are controversial. The aim of this study was to measure luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) release from the pituitary after either intracerebroventricular (ICV) injection or infusion of SP or its...
Behavioural effects of intracerebroventricularly-injected (icv) LHRH were studied in female rats. Locomotor and exploratory activities as well as irritability were determined. A pronounced inhibitory effect of 10µg doses of LHRH was found. At 100/µg doses of LHRH, barrel behaviour was observed. We conclude that LHRH can modify the activity of central serotonergic receptors in rats.
The effect of γ-aminobutyric acid-receptor agonists, GABA and muscimol on the pituitary-adrenocortical activity, measured indirectly through corticosterone secretion, and the receptors involved were investigated in conscious rats. GABA given ip induced a dual effect, in lower dose (10mg/kg) it significantly decreased the resting serum corticosterone levels while in higher doses (100-500mg/kg) it considerably...
In uretane-chloralose anaesthesia the pituitary gland was exposed by transpharyngeal approach in rats. The anterior lobe was removed and the posterior lobe was incubated in situ, that is in conditions of anatomical integrity of the hypothalamus with the posterior pituitary lobe. The 15-min samples of the medium incubating the posterior pituitary lobe in situ were collected. Vasopressin (AVP) content...
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