Search results for "rats"
showing 10 items of 3537 documents
Relaxant effect of dopamine on the isolated rat uterus.
1988
The effect of dopamine was studied on the isolated uterus of diethylstilboestrol-treated rats. Dopamine, at concentrations (10(7)-10(-4) M) produced a concentration-dependent relaxation in the K+-depolarized rat uterus. On a molar basis, dopamine was about 500 times less potent than adrenaline in relaxing the uterus, the maximum degree of relaxation obtained with both drugs was the same. Pretreatment of the rats with reserpine (5 mg/kg) did not produce any modification of the dose-response curve to dopamine. Similarly, cocaine (3 x 10(-6) M) failed to modify the relaxant effect of dopamine. The dopamine induced relaxation was inhibited by propranolol (10(-9)-10(-7) M) in a dose-dependent ma…
Effect of histamine on the longitudinal and circular muscle of the oestrogen dominated rat uterus.
1993
The response of the longitudinal and circular myometrial strips to histamine was studied in oestrogen-treated rats. Histamine produced a dose-related inhibitory response in KCl-contracted longitudinal and circular uterine strips. Histamine was equipotent in producing the relaxant response but the maximal effect achieved in the longitudinal muscle was higher than the circular one. Ranitidine antagonized the histamine-induced relaxation with a similar dose ratio in both longitudinal and circular strips. Clemizole and reserpine treatment did not produce any modification of the dose-response curve to histamine. In the longitudinal and circular strips which were not preconstricted by KCl, neithe…
Retinoids induce MMP-9 expression through RARalpha during mammary gland remodeling.
2007
Retinoic acid (RA) is a signaling molecule in the morphogenesis of the mammary gland, modulating the expression of matrix metalloproteinases (MMPs). The aim of this paper was to study the role of RA during weaning, which consists of three events: apoptosis of the secretory cells, degradation of the extracellular matrix, and adipogenesis. CRABP II and CRBP-1 carrier proteins increased significantly during weaning compared with lactating glands but reverted to control values after the litter resuckled. The effects of RA are mediated by the nuclear receptors RARalpha, RARbeta, RARgamma, and RXRalpha, which underwent an increase in protein levels during weaning. In an attempt to elucidate the R…
Innovative barriers for peritoneal adhesion prevention: liquid or solid? A rat uterine horn model.
2005
Objective To compare the effects of solid barriers (PDLA membrane and foil, Interceed), innovative barrier solutions (Adept and Hyalobarrier Gel, phospholipid emulsion), and Ringer’s lactate solution in preventing postsurgical peritoneal adhesions in the rat. Design Prospective, randomized experimental study. Setting Rat model in an academic research environment. Animal(s) Female, nonpregnant Wistar rats. Intervention(s) Standardized surgical injuries were applied to the parietal and visceral peritoneum and the uterine horns. The barrier agents were applied and the wound was closed. A second-look laparoscopy was performed 31 days after surgery to assess adhesion formation. Main Outcome Meas…
Thyroid hormones induce sumoylation of the cold shock domain-containing protein PIPPin in developing rat brain and in cultured neurons.
2006
We previously identified a cold shock domain (CSD)-containing protein (PIPPin), expressed at high level in brain cells. PIPPin has the potential to undergo different post-translational modifications and might be a good candidate to regulate the synthesis of specific proteins in response to extracellular stimuli. Here we report the effects of thyroid hormone (T3) on PIPPin expression in developing rat brain. We found that a significant difference among euthyroid- and hypothyroid- newborn rats concerns sumoylation of nuclear PIPPin, that is abolished by hypothyroidism. Moreover, T3-dependence of PIPPin sumoylation has been confirmed in cortical neurons purified from brain cortices and culture…
Modulation of hippocampal acetylcholine release after fimbria-fornix lesions and septal transplantation in rats
1997
Abstract Female Long–Evans rats sustained electrolytic lesions of the fimbria and the dorsal fornix causing a partial lesion of the septohippocampal pathway. Two weeks later, the rats received intra-hippocampal grafts of fetal septal cell suspensions. Nine to twelve months later, the release of acetylcholine (ACh) in the hippocampus of sham-operated, lesion-only and grafted rats was measured by microdialysis. The extent of cholinergic (re)innervation was determined by acetylcholinesterase (AChE) staining and densitometry. In both lesion-only and grafted rats, the ratio of ACh release to AChE staining intensity was increased as compared to sham-operated rats, indicating a loss of endogenous …
Muscarine receptors on the rat phrenic nerve, evidence for positive and negative muscarinic feedback mechanisms.
1987
Neuronal transmitter stores of the rat phrenic nerve were labelled by incubation with [3H]choline. Release of [3H]acetylcholine was elicited by electrical nerve stimulation (100 or 1500 pulses, 5 or 25 Hz) or by high potassium (27 mmol/l) and the effects of the muscarine receptor agonist oxotremorine and the antagonist scopolamine were investigated. Neither oxotremorine nor scopolamine affected the basal tritium efflux. A low concentration of oxotremorine (10 nmol/l) enhanced and a high concentration of oxotremorine (1 μol/l) reduced the electrically evoked [3H]acetylcholine release. Likewise, the high potassium-evoked [3H]acetylcholine release was reduced by a high concentration of oxotrem…
Characterization of endogenous noradrenaline release from intact and epithelium-denuded rat isolated trachea.
1991
1. Overflow of endogenous noradrenaline (NA) from the in vitro incubated rat trachea evoked by two periods of electrical field stimulation (S1, S2 at 3 or 15 Hz) or by high potassium (60 mM) was determined by high performance liquid chromatography (h.p.l.c.) with electrochemical detection. 2. In the presence of the neuronal uptake inhibitor desipramine, the alpha 2-adrenoceptor antagonist, yohimbine, enhanced the overflow of NA evoked by stimulation at 3 Hz by about 100% suggesting the presence of presynaptic inhibitory autoreceptors on the sympathetic nerves innervating the trachea. 3. When desipramine and yohimbine were present throughout the experiments, the overflow of NA evoked by the …
Response to dopamine agonists of the rat isolated uterus.
1993
1. Quinpirole did not produce any effect in isolated uterus from oestrogenized rats even when it is contracted by KCl (37 mM). 2. Fenoldopam produced a relaxant effect on rat isolated uterus contracted by KCl which was not significantly modified by SCH 23390. 3. Reserpine decreased the effect of the lowest doses of fenoldopam. In reserpinized rats, propranolol (10(-9), 10(-8), 10(-7) M) antagonized the effect of the lowest doses of fenoldopam and neither SCH 23390, sulpiride nor ranitidine modified the effect of fenoldopam. 4. The results confirm our previous finding that DA1-receptors are not functional in our preparation. The effect of fenoldopam was partially due to a catecholamine-relea…
Secretory effect of azodisalicylate (azodisal sodium) on the short circuited mucosa of the rat ileum in vitro.
1988
Azodisalicylate (ADS) is one of the newly developed substitutes of sulphasalazine consisting of two molecules of 5-amino-salicylic acid. Azodisalicylate caused diarrhoea in some patients, apparently caused by an antiabsorptive secretagogue action of this compound. The mechanism of this was studied in the short circuited isolated mucosa of the rat ileum. Mucosal addition of ADS increased the potential difference (PD) and short circuit current (Isc) at a concentration of 1.3.10(-4) mol/l (4 mg/dl) with maximal effects at 1.3.10(-3) mol/l (40 mg/dl). Epithelial resistance was only slightly decreased at the higher concentrations of 40 and 100 mg/dl. Serosal ADS had no effect on electrical param…