Isoflurane but not halothane minimum alveolar concentration-sparing response of dexmedetomidine is enhanced in rats chronically treated with selective α2-adrenoceptor agonist

2012 ◽  
Vol 46 (3) ◽  
pp. 215-219
Author(s):  
M Santos ◽  
J A Ibancovichi ◽  
I Millán ◽  
F J Tendillo
Keyword(s):  
Wistar Rats ◽  
Low Dose ◽  
Saline Solution ◽  
Minimum Alveolar Concentration ◽  
Chronic Administration ◽  
Naive Group ◽  
Adrenoceptor Agonist ◽  
Female Wistar Rats ◽  
Intraperitoneal Dose ◽  
Sparing Effect

Halothane minimum alveolar concentration (MAC)-sparing response is preserved in rats rendered tolerant to the action of dexmedetomidine. It has been shown that halothane and isoflurane act at different sites to produce immobility. The authors studied whether there was any difference between halothane and isoflurane MAC-sparing effects of dexmedetomidine in rats after chronic administration of a low dose of this drug. Twenty-four female Wistar rats were randomly allocated into four groups of six animals: two groups received 10 μg/kg intraperitoneal dexmedetomidine for five days (treated groups) and the other two groups received intraperitoneal saline solution for five days (naive groups) prior to halothane or isoflurane MAC determination (one treated and one naive group of halothane and one treated and one naive group of isoflurane). Halothane or isoflurane MAC determination was performed before (basal) and 30 min after an intraperitoneal dose of 30 μg/kg of dexmedetomidine (post-dex) from alveolar gas samples at the time of tail clamp. Administration of an acute dose of dexmedetomidine to animals that had chronically received dexmedetomidine resulted in a MAC-sparing effect that was similar to that seen in naive animals for halothane; however, the same treatment increased the MAC-sparing response of dexmedetomidine for isoflurane. Isoflurane but not halothane MAC-sparing response of acutely administered dexmedetomidine is enhanced in rats chronically treated with this drug.

scholarly journals UTILIZAÇÃO DE PRÓPOLIS OU MEL NO TRATAMENTO DE FERIDAS LIMPAS INDUZIDAS EM RATOS

2003 ◽  
Vol 8 (1) ◽  
Author(s):  
S.C. RAHAL ◽  
A.P.F.R.L. BRACARENSE ◽  
C.Y. TANAKA ◽  
T.P. GRILLO ◽  
C.A.L. LEITE
Keyword(s):  
Inflammatory Response ◽  
Histological Examination ◽  
Wistar Rats ◽  
Saline Solution ◽  
Skin Wound ◽  
Histopathologic Examination ◽  
Thoracic Region ◽  
Initial Weight ◽  
Female Wistar Rats

O trabalho objetivou verificar a influência do mel e do propólis na cicatrização de feridas limpas por segunda intenção, induzidos cirurgicamente. Foram utilizados 60 ratos, Wistar, fêmeas, com peso inicial entre 200 e 250 gramas, divididos em três grupos de vinte animais. Produziu-se uma ferida cutânea limpa na região torácica lateral esquerda e os animais foram submetidos aos seguintes tratamentos: grupo I – própolis, grupo II – mel e grupo III – solução fisiológica 0,9% (controle). Com três, sete, 14 e 21 dias pós-operatórios, as feridas foram mensuradas e cinco ratos de cada grupo submetidos à eutanásia, para proceder exame histológico. A análise estatística das áreas das feridas não revelou diferenças significativas entre efeito de cada tratamento e número de dias após o tratamento. Histologicamente, os tratamentos com mel e própolis induziram melhor cicatrização pela redução da resposta inflamatória, havendo reepitelização mais rápida com o própolis. Use of propolis or honey in the treatment of clean wounds induced in rats Abstract Sixty female Wistar rats, initial weight from 200 to 250 g, were divided in three groups of twenty animals each. A clean skin wound was produced at the left lateral thoracic region. The wounds were treated with propolis (G1), honey (G2) and 0.9% saline solution (G3 – control). Wounds were measured and five rats were euthanatized at 3, 7, 14 and 21 days postoperative to perform the histopathologic examination. There were no statistical differences among the effect of each treatment and number of days after the treatment. The histological examination showed that honey and propolis treatments induced better healing compared to saline solution due to the reduction of the inflammatory response, but the reepitelization was faster using propolis.

The apoptotic effect of midazolam on the salivary gland of rats and the reversal effect by pilocarpine

2018 ◽  
Vol 96 (9) ◽  
pp. 898-901 ◽  
Author(s):  
Mariana Rinaldi ◽  
Aline Cristina Batista Rodrigues Johann ◽  
Patrícia Vida Cassi Bettega ◽  
Fábio Rocha ◽  
Sérgio Aparecido Ignácio ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Wistar Rats ◽  
Saline Solution ◽  
Chronic Administration ◽  
Apoptotic Index ◽  
The Other ◽  
Parotid Glands ◽  
Control Groups ◽  
Reversal Effect ◽  
Apoptotic Effect

To evaluate the apoptosis in parotid glands of rats treated with midazolam associated or not with pilocarpine, 60 Wistar rats were assigned to 6 groups: control groups received saline solution for 30 days (S30) and 60 days (S60) and the other groups received pilocarpine for 60 days (P60), midazolam for 30 days (M30), midazolam for 30 days and 30 days of saline (M30 + S30), and finally midazolam for 30 days and 30 days of midazolam and pilocarpine (M30 + MP30). Histological sections were subjected to the TdT-mediated dUTP-biotin nick and labeling technique. The number of positive and negative cells was quantified, calculating the apoptotic index. ANOVA at 2 criteria and Tukey’s test were used. A greater apoptotic index was observed in the M30 (52.79 ± 9.01) and M30 + S30 (62.43 ± 8.52) groups when compared with the S30 (37.94 ± 5.94) and S60 (31.85 ± 9.18) groups, respectively (p < 0.05). There was no difference between M30 + MP30 (30.98 ± 6.19) and S60 (31.85 ± 9.18) groups regarding apoptotic index. Chronic administration of midazolam has been shown to increase the number of apoptotic cells in the parotid glands of rats. However, pilocarpine inhibited this effect, thus inhibiting the apoptosis.

scholarly journals The effects of acute and chronic administration of n-6 and n-3 polyunsaturated fatty acids on ethanol-induced gastric haemorrhage in rats

1992 ◽  
Vol 67 (3) ◽  
pp. 501-507 ◽  
Author(s):  
B. Hunter ◽  
G. S. A. McDonald ◽  
M. J. Gibney
Keyword(s):  
Fish Oil ◽  
Micellar Solution ◽  
Wistar Rats ◽  
Gastric Lesion ◽  
Control Diet ◽  
Chronic Administration ◽  
Standard Laboratory ◽  
Weanling Rats ◽  
Female Wistar Rats ◽  
Maize Oil

Female weanling rats in three equal groups (n12) were given orally by intubation 1 ml micellar solution of taurocholic aicd (10 mM) and either arachidonic acid (20:4n−6), linoleic acid (18:2n−6) or eicosapentaenoic acid (20:5n−3) at a concentration of 120 mM. After 1 h the rats were given intragastrically 2 ml absolute ethanol and were killed 1 h later. Rats given oral 20:4n−6 showed a significant reduction (P< 0.05) in the extent (%) of gastric mucosal haemorrhage compared with either the rats given 20:5n−3 or 18:2n−6 (8.3 (SD 7.3), 23.2 (SD 10.4) and 21.4 (SD 10.4)) respectively. In a second experiment, four equal groups (n12) of female Wistar rats were fed for 5 weeks on either a control diet of standard laboratory rat food, or the same diet enriched with either maize oil or fish oil or butterfat at a level of 100 g/kg. Following a 24 h fast the rats received an intragastric dose of 2 ml ethanol and were killed 1 h later. Examination of the extent (%) of gastric lesion showed a significant reduction (P< 0.05) with the feeding of either maize oil or fish oil compared with the controls (12.2 (SD 8.2), 15.3 (SD 13.2) and 29.3 (SD 14.0) respectively). The butterfat diet was not significantly different from the control diet (23.8 (SD 8.1)).

scholarly journals Evaluation of the toxic influence of vitamin E (dl-alpha-tocopheryl acetate) and treatment with aqueous extracts of cinnamon or anise on lipid profile and liver functions of female wistar rats

2017 ◽  
Vol 5 (2) ◽  
pp. 248
Author(s):  
Sabah Ibrahim ◽  
Murwan Sabahelkhier
Keyword(s):  
Vitamin E ◽  
Wistar Rats ◽  
Low Dose ◽  
Density Lipoprotein ◽  
Control Group ◽  
High Dose ◽  
Toxic Dose ◽  
Liver Functions ◽  
Female Wistar Rats ◽  
Better Than

The toxic effects of vitamin E and its treatment with aqueous extracts of Cinnamon or anise on lipid profile and liver functions of female wistar rats were examined for six weeks during September 2016 at labs in al-Neelain University. 18 rats were divided into six groups: 1. negative control group (sunflower oil), 2. Positive control group and rest groups given (1500 mg/Kg/BW/day of Vitamin E). After two hours, the four treated groups received a low dose (2.13g/Kg) and a high dose (3.20g/Kg) 20g/Kg from Cinnamon aqueous extract (CAE) and Anise aqueous extract (AAE). At the end rats were sacrificed then serum and liver tissues were analyzed. Vitamin E toxic dose had caused a significant increase in serum Triglycerides (TG), Alanine amino transferase (ALT) levels, while it decreased the levels of High-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol (TC) and Aspartate amino transferase (AST). All treatments decreased TG and ALT levels. CAE low dose significantly increased TC, LDL and HDL levels. CAE high dose caused a significant decrease in AST, TC, and LDL. Both doses of AAE, caused significant increases on AST levels, and only anise low dose caused a significant decrease on TC and LDL levels. Vitamin E toxic dose caused severe fatty change in liver histology, which was near normal in both doses of CAE with a small necrosis in a low dose. Only AAE low dose normalized the liver. To conclude Vitamin E oral administration with a dose of (1500 mg/Kg) induced liver injury with an elevation in ALT and TG levels, which was significantly ameliorated by both treatments. Cinnamon was better than anise in ameliorating the toxicity. Cinnamon high dose was better than Cinnamon low dose; in contrast anise low dose was better than Anise high dose.

Effects of Naloxone on Opioid-induced Hyperalgesia and Tolerance to Remifentanil under Sevoflurane Anesthesia in Rats

2013 ◽  
Vol 118 (5) ◽  
pp. 1160-1169 ◽  
Author(s):  
Delia Aguado ◽  
Mariana Abreu ◽  
Javier Benito ◽  
Javier Garcia-Fernandez ◽  
Ignacio A. Gómez de Segura
Keyword(s):  
Wistar Rats ◽  
Low Dose ◽  
Minimum Alveolar Concentration ◽  
Opioid Tolerance ◽  
Sevoflurane Anesthesia ◽  
Male Adult ◽  
Treatment Groups ◽  
Opioid Induced Hyperalgesia ◽  
Baseline Values ◽  
Mechanical Thresholds

Abstract Background: Opioid antagonists at ultra-low doses have been used with opioid agonists to prevent or limit opioid tolerance. The aim of this study was to evaluate whether an ultra-low dose of naloxone combined with remifentanil could block opioid-induced hyperalgesia and tolerance under sevoflurane anesthesia in rats. Methods: Male adult Wistar rats were allocated into one of four treatment groups (n = 7), receiving remifentanil (4 µg·kg−1·min−1) combined with naloxone (0.17 ng·kg−1·min−1), remifentanil alone, naloxone alone, or saline. Animals were evaluated for mechanical nociceptive thresholds (von Frey) and subsequently anesthetized with sevoflurane to determine the baseline minimum alveolar concentration (MAC). Next, treatments were administered, and the MAC was redetermined twice during the infusion. The experiment was performed three times on nonconsecutive days (0, 2, and 4). Hyperalgesia was considered to be a decrease in mechanical thresholds, whereas opioid tolerance was considered to be a decrease in sevoflurane MAC reduction by remifentanil. Results: Remifentanil produced a significant decrease in mechanical thresholds compared with baseline values at days 2 and 4 (mean ± SD, 30.7 ± 5.5, 22.1 ± 6.4, and 20.7 ± 3.7g at days 0, 2, and 4, respectively) and an increase in MAC baseline values (2.5 ± 0.3, 3.0 ± 0.3, and 3.1 ± 0.3 vol% at days 0, 2, and 4, respectively). Both effects were blocked by naloxone coadministration. However, both remifentanil-treated groups (with or without naloxone) developed opioid tolerance determined by their decrease in MAC reduction. Conclusions: An ultra-low dose of naloxone blocked remifentanil-induced hyperalgesia but did not change opioid tolerance under inhalant anesthesia. Moreover, the MAC increase associated with hyperalgesia was also blocked by naloxone.

scholarly journals Ethanol reduces the minimum alveolar concentration of sevoflurane in rats

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Johannes Müller ◽  
Walter Plöchl ◽  
Paul Mühlbacher ◽  
Alexandra Graf ◽  
Anne-Margarethe Kramer ◽  
...  
Keyword(s):  
Placebo Group ◽  
Wistar Rats ◽  
Animal Experiment ◽  
Low Dose ◽  
Minimum Alveolar Concentration ◽  
High Dose ◽  
Trauma Patients ◽  
Regression Methods ◽  
Ethanol Group ◽  
Bootstrap Estimate

AbstractA high number of trauma patients are under the influence of alcohol. Since many of them need immediate surgical procedures, it is imperative to be aware of the interaction of alcohol with general anesthesia. To counter challenges that arise from clinical studies, we designed an animal experiment in which 48 adult Wistar rats either received 1 g · kg−1 ethanol, 2 g · kg−1 ethanol or placebo via intraperitoneal application. Subsequently, they were anesthetized with an individual concentration of sevoflurane. The minimum alveolar concentration (MAC) of the different groups was assessed using Dixon’s up-and-down design and isotonic regression methods. The bootstrap estimate of the MAC of sevoflurane in the placebo group was 2.24 vol% (95% CI 1.97–2.94 vol%). In the low dose ethanol group, the bootstrap estimate was 1.65 vol% (95% CI 1.40–1.98 vol%), and in the high dose ethanol group, it was 1.08 vol% (95% CI 0.73–1.42 vol%). We therefore report that intraperitoneal application of 1 g · kg−1 or 2 g · kg−1 ethanol both resulted in a significant reduction of the MAC of sevoflurane in adult Wistar rats: by 26.3% and 51.8% respectively as compared to placebo.

Reduction of isoflurane MAC with buprenorphine and morphine in rats

2000 ◽  
Vol 34 (3) ◽  
pp. 252-259 ◽  
Author(s):  
A. B. Criado ◽  
I. A. Gómez de Segura ◽  
F. J. Tendillo ◽  
F. Marsico
Keyword(s):  
Respiratory Depression ◽  
Postoperative Period ◽  
Wistar Rats ◽  
Minimum Alveolar Concentration ◽  
Noxious Stimulus ◽  
Before And After ◽  
Dose Dependent Fashion ◽  
Male Wistar Rats ◽  
Sparing Effect ◽  
Dose Dependent

Preoperative analgesics are being increasingly used to provide analgesia in the intraoperative and postoperative period. Opioids reduce anaesthetic requirements, although the effect varies with the different drug and species. The aim of this work was to determine whether buprenorphine reduces the minimum alveolar concentration (MAC) of isoflurane in a dose-related fashion, and whether this effect is similar to morphine when clinical doses of both drugs are used in the rat. Thirty-six male Wistar rats were anaesthetized with isoflurane, and MAC was determined before and after the administration of either buprenorphine or morphine. MAC of isoflurane was determined from alveolar gas samples when a standard noxious stimulus, in the form of a tail clamp, was applied. The duration and degree of reduction of the MAC of isoflurane were recorded. Basic cardiovascular and respiratory measurements were also recorded. Buprenorphine (10, 30 and 100 μg/kg) and morphine (1, 3 and 10 mg/kg) reduced in a dose-dependent fashion the MAC of isoflurane by 15%, 30% and 50%, respectively. Buprenorphine resulted in less cardiovascular and respiratory depression and had a longer-lasting action than morphine. In conclusion, buprenorphine has a dose-related isoflurane sparing effect in the rat similar to that caused by morphine at clinical doses of both drugs.

Sub-chronic palladium nanoparticle effects on the endocrine reproductive system of female Wistar rats: Preliminary data

2019 ◽  
Vol 35 (6) ◽  
pp. 403-409 ◽  
Author(s):  
Veruscka Leso ◽  
Luca Fontana ◽  
Alessandro Marinaccio ◽  
Kerstin Leopold ◽  
Caterina Fanali ◽  
...  
Keyword(s):  
Reproductive System ◽  
Wistar Rats ◽  
Molecular Mechanisms ◽  
Low Dose ◽  
Endocrine System ◽  
Regulatory System ◽  
Reproductive Function ◽  
Intravenous Route ◽  
Childbearing Age ◽  
Female Wistar Rats

The technologically interesting properties of palladium nanoparticles (Pd-NPs) allowed their widespread industrial application, although concerns emerged on increasing general and occupational levels of exposure. In this context, to assess the toxicological behavior of Pd-NPs, and particularly their endocrine disruptive potential, has become a public health priority. Therefore, we evaluated Pd-NP impact on the female endocrine reproductive system of Wistar rats sub-chronically treated for 90 days with increasing doses of this xenobiotic (0.12, 1.2, and 12 µg/kg, administered at days 1, 30, and 60 for cumulative doses of 0.36, 3.6, and 36 µg/kg) via the intravenous route. In this regard, we investigated potential alterations in different sex hormone, for example, estradiol, follicle-stimulating hormone (FSH), luteinizing hormone, progesterone, and testosterone, serum concentrations. All treated groups showed significantly greater levels of FSH compared to controls, suggesting a possible impact of Pd-NPs on the regulatory system that controls the normal physiology of female reproductive function. Although relevant, since obtained under sub-chronic, low-dose conditions of exposure resembling those encountered in real-world scenarios, the present results are preliminary and require confirmation as well as identification of the possible underlining molecular mechanisms. From a public and occupational health perspective, implications for the reproductive health of exposed subjects and the next generations of women exposed during their childbearing age or pregnancy should be elucidated. This information is essential to elaborate adequate preventive strategies for assessing and controlling possible Pd-NPs adverse effects on the endocrine system.

Effects of the α2-adrenoceptor agonist, guanfacine, on growth rate, glucose, corticosterone, insulin and energy partitioning in rats

2002 ◽  
Vol 74 (3) ◽  
pp. 455-459
Author(s):  
C. Gazzola ◽  
W. G. Spiers
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Fat ◽  
Wistar Rats ◽  
Free Access ◽  
Subcutaneous Injections ◽  
Adrenoceptor Agonist ◽  
Female Wistar Rats ◽  
Total Body ◽  
Body Energy

AbstractIn experiment 1, female Wistar rats (no. = 24) with free access to food were treated daily for 8 days with subcutaneous injections of saline or 0·5 mg/kg of the α2-adrenoceptor agonist, guanfacine hydrochloride. In experiment 2, female Wistar rats (no. = 24), restricted to 12 g food per day were treated daily for 45 days with subcutaneous injections of 1 μl/g body weight saline containing 0, 0.001, 0.025 or 0·5 mg/kg guanfacine hydrochloride. In experiment 1, the control and treated groups consumed similar amounts of food but the guanfacine-treated animals gained less body weight (P 0.05) and less muscle mass (P 0.01). The treated animals had pronounced glucosuria (P < 0.05) during the whole treatment period. At slaughter, the treated group had higher blood glucose (P < 0.001) and serum corticosterone (P < 005) but insulin concentrations were not different. In experiment 2, only the 0.5 mg/kg dose of guanfacine had significant effects. Resting oxygen consumption on day 29 of treatment was proportionately 0.10 lower in this group compared with controls (P < 0.05). There was no effect of treatment on growth rate. After 46 days, the 0·5 mg/kg treatment group had proportionately 0·35 more body fat (P < 0.01), higher body fat content (P < 0.01), higher total body energy (P < 0.05) and higher total body energy content (P < 0.05). Experiment 1 linked reduced growth rate with increased corticosterone concentrations and experiment 2 suggested the mechanism may be a repartitioning of energy storage to lipid. However, it was not determined whether these consequences were a direct effect of guanfacine or a secondary effect due to corticosterone. In spite of reductions in energy expenditure, guanfacine retards growth in rats and mice, but not in cattle where growth is enhanced. Thus rodents may have a limited usefulness as models for studies of α2-adrenoceptor agonists in cattle.

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