Estimates of genetic parameters for rumination time, feed efficiency, and methane production traits in first-lactation Holstein cows.

The large-scale recording of traits such as feed efficiency (FE) and methane emissions (ME) for use in genetic improvement programs is complex, costly, and time-consuming. Therefore, heritable traits that can be continuously recorded in dairy herds and are correlated with FE and ME traits could provide useful information for genetic evaluation. Rumination time has been suggested to be associated with FE, methane production (MeP; ME in g/d), and production traits at the phenotypic level. Therefore, the objective of this study was to investigate the genetic relationships among rumination time (RT), FE, methane and production traits using 7,358 records from 656 first-lactation Holstein cows. The estimated heritabilities were moderate for RT (0.45 ± 0.14), MeP (0.36 ± 0.12), milk yield (0.40 ± 0.08), fat yield (0.29 ± 0.06), protein yield (0.32 ± 0.07), and energy-corrected milk (0.28 ± 0.07), but were low and nonsignificant for FE (0.15 ± 0.07), which was defined as the residual of the multiple linear regression of DMI on energy-corrected milk and metabolic body weight. A favorable negative genetic correlation was estimated between RT and MeP (-0.53 ± 0.24), whereas a positive favorable correlation was estimated between RT and energy-corrected milk (0.49 ± 0.11). The estimated genetic correlation of RT with FE (-0.01 ± 0.17) was not significantly different from zero but showed a trend of a low correlation with dry matter intake (0.21 ± 0.13). These results indicate that RT is genetically associated with MeP and milk production traits, but high standard errors indicate that further analyses should be conducted to verify these findings when more data for RT, MeP, and FE become available.

A comparative evaluation of methods for estimating the colostrum quality in sows / Avaliação comparativa de métodos para estimar a qualidade do colostro em porcas

Colostrum is the main source of immunoglobulins (Ig) for neonate piglets and plays a crucial role within the health and growth of the piglet. Currently in pig farming, there are still no widespread practical methods for measuring the Ig concentration in colostrum at herd level. We evaluated sows' colostrum IgG concentration using an optical and a digital Brix refractometer and their performance was correlated to an IgG ELISA test, and flow cytometry. Colostrum concentrations of IgG and IgA averaged 74.05 ± 21.37mg/mL and 20.2 ± 5.32mg/mL respectively. The mean value of the Brix percentages for optical refractometer was 26.32%, and for digital was 28.32%. The Brix refractometer measurements of colostrum samples presented high correlation for IgG content analyzed by ELISA (Optical = 0.74, Digital = 0.87; P <0.001). Considering the immunophenotyping, the values for IgG and IgA lymphoblasts indicated a highly significant relationship to ELISA (IgG=0.77, IgA=0.84; P<0.001). The Brix refractometer can be considered a useful tool to be included in a colostrum monitoring program to improve potentially neonatal health. In addition, we demonstrated that flow cytometry can be an important tool to analyze and characterize the immunological potential of sow colostrum.(AU)

O colostro é a principal fonte de imunoglobulinas (Ig) para leitões recém-nascidos e desempenha um papel crucial na saúde e no crescimento dos leitões. Atualmente, na suinocultura, ainda não existem métodos amplamente utilizados na prática de produção para medir a concentração de imunoglobulinas no colostro suíno. Avaliou-se a concentração de IgG no colostro de porcas usando refratômetros Brix óptico e digital, e o desempenho foi comparado com ELISA e citometria de fluxo. As concentrações de IgG e IgA no colostro foram 74,05 ± 21,37mg/mL e 20,2 ± 5,32mg/mL, respectivamente. A percentagem de Brix média das amostras de colostro para o refratômetro óptico foi 26,32%, e para o digital foi 28,32%. As medições dos refratômetros de Brix apresentaram elevada correlação com a concentrações de IgG medidas por ELISA (óptico=0,74, digital=0,87; P<0,001). Considerando a imunofenotipagem, os valores dos linfoblastos IgG e IgA apresentaram alta correlação com o ELISA (IgG=0,77, IgA=0,84; P<0,001). O refratômetro Brix pode ser considerado uma ferramenta útil para ser incluída em um programa de monitoramento de colostro para melhorar a saúde neonatal. Além disso, foi demonstrado que a citometria de fluxo pode ser uma ferramenta importante para analisar e caracterizar o potencial imunológico do colostro de porcas.(AU)

Brain neuroimaging of domestic cats: correlation between computed tomography and cross-sectional anatomy / Neuroimagem cerebral de gatos domésticos: correlação entre a tomografia computadorizada e a anatomia seccional

Computed tomography of the brain is necessary as part of the diagnosis of lesions of the central nervous system. In this study we used six domestic cats, male or female, aged between one and five years, evaluated by Computed Tomography (CT) examination without clinical signs of central nervous system disorders. Two euthanized animals stating a condition unrelated to the nervous system were incorporated into this study. The proposal consisted in establishing detailed anatomical description of tomographic images of normal brain of cats, using as reference anatomical images of cross sections of the stained brain and cranial part, with thicknesses similar to the planes of the CT images. CT examinations were performed with and without intravenous iodinated contrast media for live animals. With one euthanized animal, the brain was removed and immediately preserved in 10% formalin for later achievement in cross-sectional thickness of approximately 4mm and staining technique of Barnard, and Robert Brown. The head of another animal was disarticulated in the Atlanto-occipital region and frozen at -20ºC then sliced to a thickness of about 5mm. The description of visualized anatomical structures using tomography is useful as a guide and allows transcribing with relative accuracy the brain region affected by an injury, and thus correlating it with the clinical symptoms of the patient, providing additional information and consequent improvement to veterinarians during the course of surgical clinic in this species.(AU)

A tomografia computadorizada do cérebro é de suma importância como parte do diagnóstico de lesões do sistema nervoso central. Neste estudo, foram utilizados seis felinos domésticos, machos ou fêmeas, com idade entre um e cinco anos, avaliados pela tomografia computadorizada (TC), sem sinais clínicos de distúrbios do sistema nervoso central. Dois cadáveres indicando a condição relacionada com o sistema nervoso foram incorporados ao presente estudo. A proposta consistiu na criação da descrição anatômica detalhada das imagens tomográficas de cérebro normal de gatos, usando como referência a imagens anatômicas de secções transversais do cérebro coradas, realizadas com espessuras similares aos planos das imagens tomográficas. Exames de TC foram realizados com e sem contraste iodado intravenoso para os animais vivos. Em um dos cadáveres, o cérebro foi removido e imediatamente preservado em formalina a 10% para a realização posterior da técnica de coloração de Barnard e Robert Brown, além de cortes transversais com espessura de, aproximadamente, 4mm. O crânio do outro cadáver foi desarticulado na região atlanto-occipital e congelado a -20ºC. Em seguida, foi realizado corte com espessura de cerca de 5mm. A descrição das estruturas anatômicas visualizadas foi útil e serve como guia, permitindo descrever com relativa precisão a estrutura cerebral normal ou lesionada, e, portanto, correlacionando-a com os sintomas clínicos de um paciente, o que fornece informações adicionais e consequente aprimoramento de veterinários no curso de clínica cirúrgica para essa espécie.(AU)

Six-month Follow-up of Cervical Composite Restorations Placed With a New Universal Adhesive System: A Randomized Clinical Trial.

PURPOSE: The objective of this double-blind, randomized clinical trial was to evaluate the six-month clinical performance of a new universal adhesive (Xeno Select, Dentsply) in noncarious cervical lesions (NCCLs) using two evaluation criteria: World Dental Federation (FDI) and the US Public Health Service (USPHS). METHODS AND MATERIALS: A total of 124 restorations were randomly placed in 31 patients according to the following groups: ER-D = etch-and-rinse/dry dentin; ER-M = etch-and-rinse/moist dentin; SE-et = selective enamel etching; and SET = self-etch. The composite resin EVOLUX (Dentsply) was placed incrementally. The restorations were evaluated after one week (baseline) and at six months using the FDI and USPHS criteria. Statistical analyses were performed using appropriate tests (α=0.05). RESULTS: Fifteen restorations were lost or fractured at six months (one for ER-D, three for ER-M, five for SE-et, and six for SET) (p>0.05 at six-month recall). When ER (ER-D and ER-M) was compared with SE (SE-et and SET) there was a significant difference in the retention rate after six months (p=0.001). Marginal staining and postoperative sensitivity to air were only observed in three (one for ER-M and two for SET) and two restorations (two for ER-D) in both evaluation criteria (p>0.05), respectively. Forty-seven restorations were considered to have minor discrepancies in marginal adaptation at the six-month recall using the FDI criteria (13 for ER-D, 10 for ER-M, 11 for SE-et, and 13 for SET; p>0.05 between groups). However, for all groups, a significant difference was detected when baseline and six-month data were compared (p<0.05). CONCLUSIONS: The six-month clinical behavior of Xeno Select Universal Adhesive depends on the bonding strategy used. The universal adhesive did not fulfill the American Dental Association criteria for full approval when used in the self-etch mode.

Brain caspase-3 and intestinal FABP responses in preterm and term rats submitted to birth asphyxia.

Neonatal asphyxia can cause irreversible injury of multiple organs resulting in hypoxic-ischemic encephalopathy and necrotizing enterocolitis (NEC). This injury is dependent on time, severity, and gestational age, once the preterm babies need ventilator support. Our aim was to assess the different brain and intestinal effects of ischemia and reperfusion in neonate rats after birth anoxia and mechanical ventilation. Preterm and term neonates were divided into 8 subgroups (n=12/group): 1) preterm control (PTC), 2) preterm ventilated (PTV), 3) preterm asphyxiated (PTA), 4) preterm asphyxiated and ventilated (PTAV), 5) term control (TC), 6) term ventilated (TV), 7) term asphyxiated (TA), and 8) term asphyxiated and ventilated (TAV). We measured body, brain, and intestine weights and respective ratios [(BW), (BrW), (IW), (BrW/BW) and (IW/BW)]. Histology analysis and damage grading were performed in the brain (cortex/hippocampus) and intestine (jejunum/ileum) tissues, as well as immunohistochemistry analysis for caspase-3 and intestinal fatty acid-binding protein (I-FABP). IW was lower in the TA than in the other terms (P<0.05), and the IW/BW ratio was lower in the TA than in the TAV (P<0.005). PTA, PTAV and TA presented high levels of brain damage. In histological intestinal analysis, PTAV and TAV had higher scores than the other groups. Caspase-3 was higher in PTAV (cortex) and TA (cortex/hippocampus) (P<0.005). I-FABP was higher in PTAV (P<0.005) and TA (ileum) (P<0.05). I-FABP expression was increased in PTAV subgroup (P<0.0001). Brain and intestinal responses in neonatal rats caused by neonatal asphyxia, with or without mechanical ventilation, varied with gestational age, with increased expression of caspase-3 and I-FABP biomarkers.

Brain caspase-3 and intestinal FABP responses in preterm and term rats submitted to birth asphyxia

Neonatal asphyxia can cause irreversible injury of multiple organs resulting in hypoxic-ischemic encephalopathy and necrotizing enterocolitis (NEC). This injury is dependent on time, severity, and gestational age, once the preterm babies need ventilator support. Our aim was to assess the different brain and intestinal effects of ischemia and reperfusion in neonate rats after birth anoxia and mechanical ventilation. Preterm and term neonates were divided into 8 subgroups (n=12/group): 1) preterm control (PTC), 2) preterm ventilated (PTV), 3) preterm asphyxiated (PTA), 4) preterm asphyxiated and ventilated (PTAV), 5) term control (TC), 6) term ventilated (TV), 7) term asphyxiated (TA), and 8) term asphyxiated and ventilated (TAV). We measured body, brain, and intestine weights and respective ratios [(BW), (BrW), (IW), (BrW/BW) and (IW/BW)]. Histology analysis and damage grading were performed in the brain (cortex/hippocampus) and intestine (jejunum/ileum) tissues, as well as immunohistochemistry analysis for caspase-3 and intestinal fatty acid-binding protein (I-FABP). IW was lower in the TA than in the other terms (P<0.05), and the IW/BW ratio was lower in the TA than in the TAV (P<0.005). PTA, PTAV and TA presented high levels of brain damage. In histological intestinal analysis, PTAV and TAV had higher scores than the other groups. Caspase-3 was higher in PTAV (cortex) and TA (cortex/hippocampus) (P<0.005). I-FABP was higher in PTAV (P<0.005) and TA (ileum) (P<0.05). I-FABP expression was increased in PTAV subgroup (P<0.0001). Brain and intestinal responses in neonatal rats caused by neonatal asphyxia, with or without mechanical ventilation, varied with gestational age, with increased expression of caspase-3 and I-FABP biomarkers.

Fatty acid profile and meat quality of young bulls fed ground soybean or ground cottonseed and vitamin E.

The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P>0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P<0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P<0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P<0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P<0.05) compared with SB. The Δ9-desaturase index was greater in muscle from animals fed SB (P<0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P<0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.

Cytogenetic evaluation of tannery workers in the city of Teresina, northeastern Brazil.

Assessments of chromosomal integrity and structure enable the prevention of diseases associated with the work environment, with the frequencies of chromosomal aberrations and micronuclei often being used as markers in biomonitoring. Owing to their routine manipulation of potentially toxic chemicals, tannery workers as a group merit a more thorough evaluation and discussion. This study investigated chromosomal damage in 30 workers from a tannery in the city of Teresina, the state capital of Piauí, northeast Brazil, and a control group consisting of 30 employees from a nearby accounting firm. The frequencies of chromosomal aberrations (CAs) and binucleated cell micronuclei (MN) were assessed as a measure of damage. Means were compared using the Student t-test and ANOVA-Dunnett test. Our results indicated a higher number of CAs in exposed individuals compared to the control group, including dicentric (P < 0.0001) and tricentric chromosomes (P < 0.001), and those in ring (P < 0.0001) and acentric ring forms (P < 0.001). Assessment of MN frequency demonstrated a similar trend (exposed vs control, P < 0.0001). It was concluded that the tannery workers in this study exhibited a higher incidence of genetic damage than comparable unexposed individuals. However, further research on this subject is needed, particularly in regard to potentially clastogenic agents used in the tanning process.

Meat quality and fatty acid profile of Brazilian goats subjected to different nutritional treatments.

This study evaluated the effect of feed restriction and goat genotype on meat quality. Three genotypes (Brazilian native breed Canindé; Brazilian native breed Moxotó; and F1 Boer crossbred animals obtained by crossing Boer bucks with local breed does) and three different feeding regimens (ad libitum fed, AL; restricted fed at 75% of the ad libitum, R.75; or restricted fed at 50% of the average ad libitum intake, R.50) were used. There was no difference (P>0.05) in chemical composition, total and soluble collagen, and shear force of the Longissimus lumborum muscle among genotypes. However, AL had greater amounts of soluble collagen and crude protein in the muscle (P<0.05) than R.75. No difference (P>0.05) was observed for the myofibrillar fragmentation index. The goat genotype presented few differences in their fatty acid profiles. However, goats fed ad libitum had a more favorable fatty acid profile for human health with greater concentrations of oleic acid, unsaturated fatty acids, and conjugated linoleic acid.

Fatty acid profile, color and lipid oxidation of meat from young bulls fed ground soybean or rumen protected fat with or without monensin.

The objective of the present study was to evaluate the meat quality and fatty acid (FA) profile of the muscle and subcutaneous fat of young bulls fed ground soybean grain (SB) or rumen protected fat (RPF) with (230 mg head(-1) day(-1)) or without monensin. Forty animals with an initial weight of 359 kg were allotted in a 2×2 factorial arrangement of treatments. The use of monensin increased the arachidonic and α-linolenic acids in the longissimus dorsi (LD) muscle and subcutaneous fat, respectively (P<0.05). The meat from the animals receiving RPF had greater C18:1 content (P<0.01). The CLA and C18:2 contents were greater in the LD muscle of the animals fed SB (P<0.01). However, α-C18:3 was greater in the LD muscle of animals fed RPF (P<0.01). In the subcutaneous fat, SB reduced C12:0 and C14:0 contents (P<0.01) and increased C18:0 (P<0.05). The inclusion of RPF increased the C18:1 and CLA contents (P<0.01) in the subcutaneous fat. Soybean elevated PUFA contents and increased susceptibility of muscle and subcutaneous fat to lipid oxidation.

Qualitative characteristics of meat from young bulls fed different levels of crude glycerin.

The objective was to evaluate the fatty acid profile and qualitative characteristics of meat from young bulls fed crude glycerin. Forty-four animals with an initial live weight of 368 ± 4 kg were used in a completely randomized design, with four treatments: no glycerin or addition of 6, 12 or 18% glycerin. The animals were slaughtered with 519.5 ± 14.9 kg of live weight. The meat characteristics assessed were chemical composition, shear force, fatty acid concentration, color and lipid oxidation. The addition of glycerin increased the content of ether extract (P<0.05) in the muscle. A linear increase was observed (P<0.05) in the oleic acid contents (C18:1 cis 9). The saturated fatty acid (SFA) contents linearly decreased in the muscle as a function of glycerin addition. The lightness (L*) and yellowness (b*) indices increased with the use of crude glycerin (P<0.05). The crude glycerin increased the intramuscular fat and oleic acid content in the longissimus dorsi muscle.

The effect of palm oil addition to the diet of dairy sheep on the immune response.

The aim of this study was to evaluate whether a diet based on palm oil has any influence on the immune response and on the number of eggs per gram of faeces (EPG) of gastrointestinal nematodes (GIN) in dairy sheep. To address this issue, 30 ewes in early lactation were confined and divided into three groups (n = 10) receiving a daily isoproteic and isoenergetic diet. Palm oil was added to the feed at different concentrations: 0% (control; group A), 4% (group B) and 6% (group C). The animals were treated with levamisole 10 days before the beginning of the experiment. Faecal samples were collected and analysed for EPG on day zero of the experiment. On days 60 and 120, individual faecal and blood samples were collected, and the FAMACHA(©) score for assessing clinical anaemia was carried out. The groups receiving palm oil showed a significant reduction in EPG in relation to the control group (A) on day 120. Serum immunoglobulin levels (IgG, IgM and IgE) and proinflammatory cytokine levels (TNF-α, IL-1 and IL-6) were significantly increased on days 60 and 120 (p < 0.05) in groups B and C. Therefore, these results suggest that palm oil stimulates the immune response in sheep, thus reducing EPG of GIN. The hypothesis that palm oil has direct anthelmintic activity should be tested in future studies.

Comparison of the effect of different methods of molt: production and welfare evaluation.

The purpose of this study was to evaluate alternative molting protocols assessing hen welfare and performance during and after molt. Hyline W-36 pullets were housed at 15 wk of age, and their egg production was obtained during this first cycle. When birds were 80 wk, the following molting treatments were applied: a conventional molt consisting of 10 d of fasting followed by cracked corn for 8 d and a pullet developer diet for 10 d; and 4 alternative molting programs: a soy hulls-based diet (12% CP, 1,455 kcal/kg of ME, and 1.38% Ca) offered for 14 d followed by cracked corn for 4 d and a pullet developer diet for 10 d; and the other 3 molt regimens consisted of feeding soy hulls for 4, 8, or 12 d followed by 10, 6, or 2 d, respectively, of a soy hulls-based diet and 4 d of cracked corn plus 10 d of a pullet developer diet. A nonmolted group of birds was fed a laying hen diet during the experimental period. Hen-day egg number was recorded daily for 56 wk (through 80-136 wk of age). The nonmolted hens showed lower hen-day production and fewer intact eggs and a higher number of cracked and shell-less eggs compared with those of the molted hens (P < 0.0001). A significant treatment by age effect (P < 0.0001) was observed for the variables of high-density lipoproteins and triglycerides. Control hens showed the lowest high-density lipoprotein concentration and the highest triglyceride levels at 84 wk of age when compared with all treatments. The lack of difference in heterophil-to-lymphocyte ratio during molt suggests little influence of molting protocols on this variable. Regardless of the treatments, molting was deleterious to bone quality. A high mobilization of Ca through bone resorption for eggshell formation could explain the results obtained. Behavioral patterns coincided with a decline in frustration activities and an increase in alertness as molt proceeded until 83 wk of age. Alternative molting diets consisting of soybean hulls were successful in providing acceptable postmolt egg production performance.

Antinociceptive effect on mice of the hydroalcoholic fraction and (-) epicatechin obtained from Combretum leprosum Mart & Eich.

Previous studies on Combretum leprosum, a tree growing in the Northeastern states of Brazil, have shown antinociceptive effects of the ethanol extract of its leaves and bark, but studies examining its constituents are rare. The objective of this study was to evaluate the antinociceptive effect of the hydroalcoholic fraction (HF) of one of its constituents, the flavonoid (-) epicatechin (EPI), administered orally to mice (20-30 g) in models of chemical nociception, and the possible mechanisms involved. Different doses of HF (62.5 to 500 mg/kg) and EPI (12.5 to 50 mg/kg) were evaluated in models of abdominal writhing, glutamate, capsaicin, and formalin in animals pretreated with different antagonists: naloxone, ondansetron, yohimbine, ketanserin, pindolol, atropine, and caffeine in the abdominal writhing test. To determine the role of nitric oxide, the animals were pretreated with L-arginine (600 mg/kg, ip) in the glutamate test. The HF was effective (P < 0.05) in all protocols at different doses and EPI was effective in the abdominal writhing, capsaicin and glutamate tests (P < 0.05) at doses of 25 and 50 mg/kg. However, in the formalin test it was only effective in the second phase at a dose of 25 mg/kg. The antinociceptive effect of HF was inhibited when HF was associated with yohimbine (0.15 mg/kg), ketanserine (0.03 mg/kg), and L-arginine (600 mg/kg), but not with the other antagonists. HF and EPI were effective in models of chemical nociception, with the suggested participation of the adrenergic, serotonergic and nitrergic systems in the antinociceptive effect of HF.

Antinociceptive effect on mice of the hydroalcoholic fraction and (-) epicatechin obtained from Combretum leprosum Mart & Eich

Previous studies on Combretum leprosum, a tree growing in the Northeastern states of Brazil, have shown antinociceptive effects of the ethanol extract of its leaves and bark, but studies examining its constituents are rare. The objective of this study was to evaluate the antinociceptive effect of the hydroalcoholic fraction (HF) of one of its constituents, the flavonoid (-) epicatechin (EPI), administered orally to mice (20-30 g) in models of chemical nociception, and the possible mechanisms involved. Different doses of HF (62.5 to 500 mg/kg) and EPI (12.5 to 50 mg/kg) were evaluated in models of abdominal writhing, glutamate, capsaicin, and formalin in animals pretreated with different antagonists: naloxone, ondansetron, yohimbine, ketanserin, pindolol, atropine, and caffeine in the abdominal writhing test. To determine the role of nitric oxide, the animals were pretreated with L-arginine (600 mg/kg, ip) in the glutamate test. The HF was effective (P < 0.05) in all protocols at different doses and EPI was effective in the abdominal writhing, capsaicin and glutamate tests (P < 0.05) at doses of 25 and 50 mg/kg. However, in the formalin test it was only effective in the second phase at a dose of 25 mg/kg. The antinociceptive effect of HF was inhibited when HF was associated with yohimbine (0.15 mg/kg), ketanserine (0.03 mg/kg), and L-arginine (600 mg/kg), but not with the other antagonists. HF and EPI were effective in models of chemical nociception, with the suggested participation of the adrenergic, serotonergic and nitrergic systems in the antinociceptive effect of HF.

Antinociceptive effect of Zanthoxylum rhoifolium Lam. (Rutaceae) in models of acute pain in rodents.

AIM OF THE STUDY: Zanthoxylum rhoifolium Lam. (Rutaceae) is locally known as "mamica de cadela", and its bark is popularly used for toothache and earache. The objective of this study was to investigate the antinociceptive effect of the ethanolic extract from this species' stem bark (EtOH), its fractions of partition (hexane-HEX, ethyl acetate-AcOEt, aqueous-AQ) and lupeol (a triterpene obtained from HEX) in models of acute pain. MATERIALS AND METHODS: Male and female Swiss mice (25-35 g, n=6-12 animals/group) were used to assess acute toxicity and nociception (Animal Ethics Committee/UFPI, No. 09/2008). Acute toxicity was studied up to 2 g/kg p.o. of EtOH. In the formalin test (2%, 20 microL/paw), the licking time of the stimulated paw was quantified during the first 5 min (first phase) and at 15-30 min (second phase), 1h after oral treatment with EtOH, HEX, AcOEt or saline, and 30 min after use of morphine-MOR (5 mg/kg i.p.). The same response evoked by capsaicin (2 microg/20 microL/paw) was quantified during 5 min, after administration of EtOH, HEX, AcOEt, AQ, saline and MOR. The licking time of the paw that was stimulated with glutamate (10 micromol/20 microL) was measured (15 min) after treatment with EtOH, HEX, AcOEt, AQ, lupeol, saline or MK801 (0.03 mg/kg, i.p.). Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of EtOH (250 mg/kg p.o.) and HEX (500 mg/kg p.o.). RESULTS: The animals did not exhibit any acute toxicity to EtOH (up to 2 g/kg p.o.), so it was not possible to calculate the LD50. EtOH, HEX and AcOEt (62.5-250 mg/kg) produced a significant antinociceptive effect in the formalin and capsaicin tests. However, AQ was ineffective. EtOH, HEX, AcOEt and lupeol reduced the glutamate-evoked nociceptive response, but AQ had no effect. EtOH and HEX did not alter the locomotion of animals in the open-field or rota-rod tests, which suggest a lack of a central depressant effect. CONCLUSION: The results confirm the popular use of Zanthoxylum rhoifolium as an analgesic, and contribute to the pharmacological knowledge of this species because it was shown that EtOH and its less polar partition fractions (HEX, AcOEt) have an antinociceptive effect in models of chemical nociception, and that lupeol appears to be one of the constituents responsible for this effect.

Antinociceptive effect of topiramate in models of acute pain and diabetic neuropathy in rodents.

This study assesses the antinociceptive effect induced by different dosages of topiramate (TP), an anticonvulsant drug that is orally administered in models of neuropathic pain and acute pain in rats and mice, respectively. Orally administered TP (80 mg/Kg) in mice causes antinociception in the first and second phases of a formalin test, while in doses of 20 and 40 mg/Kg it was only effective in the second phase. TP (80 mg/Kg, p.o) also exhibited antinociceptive action in the hot plate test, however, it did not have an effect in the capsaicin test in mice, nor in the model of neuropathic pain in diabetic rats. The antinociceptive effect caused by TP (80 mg/Kg, p.o) in the formalin test was reversed by prior treatment with naloxone (opioid antagonist), but not with glibenclamide (antagonist of the potassium channel), ondansetron (antagonist of the serotonin 5HT3 receptor) or cyproheptadine (antagonist of the serotonin 5HT2A receptor).The data show that TP has an important antinociceptive effect in the models of nociception induced by chemical (formalin) or thermal (hot plate) stimuli, and that the opioid system plays a part in the antinociceptive effect, as shown by formalin.