Animal Model of Video-Assisted Cecum and Ileum Instrumentation for Equine Visceral Pain Study.

This study aimed to describe an animal model for studying equine visceral pain using minimally invasive and video-assisted cecum and ileum instrumentation. The access to the cecum and ileum was affected because of a previous typhlostomy. For video-assisted distention of the cecum and ileum, a distention device, which we developed using an endotracheal Rusch probe, was used, adapted, and coupled to a cuffometer to inflate and measure the pressure of the cuff attached to its distal portion. In a video-assisted manner, the distal portion of the device was introduced into the cecum and ileum, which contained the cuff in its distal portion, properly positioning it in the lumen. The cuff of the distension device was insufflated after the measurement of baseline physiological parameters of the animals and video-assisted confirmation of its right placement in the cecum and ileum lumen (M0). Was performed in one moment through two simultaneous cuff compressions and 1 minute of animal observation to evaluate the degree of abdominal discomfort manifestations (M1). To cease these stimuli, the cuff was deflated by disconnecting the extensor of the distension device attached to its proximal portion (M2). The procedure was easily performed in most cases. Slow and progressive insufflation allowed subjective adjustment of the intensity of the pain stimulus based on behavioral manifestations. Even with a low rate of complications, the model is feasible and reproducible for studies on visceral pain and the evaluation of analgesic effects.

Subarachnoid ketamine and ketamine s (+) associated with lidocaine in sheep and goats anesthesia.

Ten male sheep (Sheep group; SGk) and seven male goats (Goat group; GGks+) were used in this study. The objective was to compare the use of racemic ketamine or ketamine S(+) associated with lidocaine on spinal anesthesia and evaluate if the drugs leads to a surgical anesthesia state, as well as to verify the cardiorespiratory, sedative and motor effects of this technique in these species. After correct placement of the needle in the subarachnoid space, 3.0 mg kg-1 of racemic ketamine (SGk) or ketamine S(+) (GGks+), both diluted in 1.5 mg kg-1 of 2% lidocaine, were administered. Evaluations were performed during orchiectomy, at times 0 (T0), 5 (T5), 10 (T10), 20 (T20), 30 (T30) and 60 (T60) minutes after subarachnoid anesthesia administration. No significant changes in heart and respiratory rates were observed in both experimental groups. All animals showed surgical analgesia and stood conscious or slightly sedated with ataxia immediately after the drugs administration (T5), allowing the execution of bilateral orchiectomy. The ataxia in SGk was classified as severe with recumbency in 80% of the animals, moderate ataxia in 10% of the animals, and mild ataxia in 10% of the animals. All goats (GGks+; 100%) presented severe ataxia and recumbency. At 60 min, animals of both groups were in standing position and with normal gait. Subarachnoid RS-ketamine and ketamine S(+) (3 mg kg-1), associated with lidocaine in sheep and goats, produces surgical anesthesia and recumbency without causing cardiorespiratory abnormalities, regurgitation and bloating.

Clinical, behavioral and antinociceptive effects of crotalphine in horses / Efeitos clínico, comportamental e antinociceptivo da crotalfina em equinos

ABSTRACT: Crotalphine is a novel analgesic peptide that acts on kappa opioid and delta receptors, causing powerful analgesia in rats submitted to inflammatory, neuropathic or oncologic models of pain. This study evaluated clinical, behavioral and antinociceptive effects caused by crotalphine in horses, employing 18 Arabian horses and it was divided in three phases. In Phase I, "clinical and behavioral effects", crotalphine did not change the latency to urinate and defecate; did not modify the values of cardiac or respiratory rates, intestinal motility and rectal temperature; and did not cause significant ataxia, head, eye and lip ptosis. In Phase II, "antinociceptive effect on intact skin at scapular or ischial region", crotalphine did not cause significant analgesia. In Phase III, "antinociceptive effect on incised skin at scapular or ischial region", crotalphine promoted effective antinociceptive effects for six hours and inhibited hyperalgesia state for three days in the ischial region of horses submitted to incisional model of inflammatory pain, but crotalphine did not evoke relevant analgesic effect on the scapular region. Concluding, intravenous injection of a single dose of crotalphine (3.8ngkg-1) did not cause important clinical or behavioral changes and promotes antinociceptive effect on incised ischial region for seven days in horses. Moreover, crotalphine did not evoke relevant anti nociceptive effect on the scapular region or in intact skin of horses.

RESUMO: A crotalfina é um novo peptídeo analgésico que atua em receptores opioides kappa e delta, causando analgesia potente em ratos submetidos a modelos de dorinflamatória, neuropática e oncológica. Este estudo avaliou os efeitos clínicos, comportamental e antinociceptivo da crotalfina em equinos, empregou 18 cavalos da raça Puro Sangue Árabe e foi dividido em três fases. Na Fase I, "efeitos clínicos e comportamentais", a crotalfina não alterou a latência para urinar e defecar; não interferiu nos valores de frequência cardíaca ou respiratória, motilidade intestinal etemperatura retal; e não causou ataxia, ptose labial, palpebral ou de cabeça significativas. Na Fase II, "efeito antinociceptivo na pele íntegra da região escapular ou isquiática", a crotalfina não gerou analgesia significativa. Na Fase III, "efeito antinociceptivo na pele incisada da região escapular ou isquiática", a crotalfina promoveu efeito antinociceptivo efetivo por seis horas e inibição da hiperalgesia por três dias na região isquiática de equinos submetidos ao modelo incisional de dor inflamatória, mas não houve analgesia relevante na região escapular. Conclui-se que uma única injeção de crotalfina (3,8ngkg-1) não causa alterações clínicas ou comportamentais importantes e promove efeito antinociceptivo na região isquiática incisionada durante sete dias em equinos. Além disso, a crotalfina não evoca efeito antinociceptivo relevante na região escapular e nem na pele intacta de cavalos.

Effects of Methadone on the Minimum Anesthetic Concentration of Isoflurane, and Its Effects on Heart Rate, Blood Pressure and Ventilation during Isoflurane Anesthesia in Hens (Gallus gallus domesticus).

The aim of this study was to measure the temporal effects of intramuscular methadone administration on the minimum anesthetic concentration (MAC) of isoflurane in hens, and to evaluate the effects of the isoflurane-methadone combination on heart rate and rhythm, blood pressure and ventilation. Thirteen healthy adult hens weighing 1.7 ± 0.2 kg were used. The MAC of isoflurane was determined in each individual using the bracketing method. Subsequently, the reduction in isoflurane MAC produced by methadone (3 or 6 mg kg(-1), i.m.) was determined by the up-and-down method. Stimulation was applied at 15 and 30 minutes, and at 45 minutes if the bird had not moved at 30 minutes. Isoflurane MAC reduction was calculated at each time point using logistic regression. After a washout period, birds were anesthetized with isoflurane and methadone, 6 mg kg(-1) i.m. was administered. Heart rate and rhythm, respiratory rate, blood gas values and invasive blood pressure were measured at 1.0 and 0.7 isoflurane MAC, and during 45 minutes after administration of methadone once birds were anesthetized with 0.7 isoflurane MAC. Fifteen minutes after administration of 3 mg kg(-1) of methadone, isoflurane MAC was reduced by 2 (-9 to 13)% [logistic regression estimate (95% Wald confidence interval)]. Administration of 6 mg kg(-1) of methadone decreased isoflurane MAC by 29 (11 to 46)%, 27 (-3 to 56)% and 10 (-8 to 28)% after 15, 30 and 45 minutes, respectively. Methadone (6 mg kg(-1)) induced atrioventricular block in three animals and ventricular premature contractions in two. Methadone caused an increase in arterial blood pressure and arterial partial pressure of carbon dioxide, while heart rate and pH decreased. Methadone, 6 mg kg(-1) i.m. significantly reduced isoflurane MAC by 30% in hens 15 minutes after administration. At this dose, methadone caused mild respiratory acidosis and increase in systemic blood pressure.

Oxidative stress in hoof laminar tissue of horses with lethal gastrointestinal diseases.

Tissue damage caused by oxidative stress is involved in the pathogenesis of several diseases in animals and man, and is believed to play a role in the development of laminitis in horses. The aim of this study was to investigate the oxidative stress associated with laminar lesions in horses with lethal gastrointestinal disorders. Laminar tissue samples of the hoof of 30 horses were used. Tissue samples were divided as follows: six healthy horses (control group-CG), and 24 horses that died after complications of gastrointestinal diseases (group suffering from gastrointestinal disorders-GDG). Superoxide dismutase (SOD2) and nitrotyrosine immunostaining and the severity of laminar lesions were evaluated. Presence of laminar lesions and immunostaining for nitrotyrosine and SOD2 were only evident in horses from the GDG group. Thus, oxidative stress may play a role in the pathogenesis of laminar lesions secondary to gastrointestinal disorders.

An update on equine laminitis / Atualização sobre laminite equina

ABSTRACT: Laminitis is a severe podal affection, which pathophysiology remains partially renowned. Ischemic, enzymatic, metabolic and inflammatory mechanisms are connected to the development of laminar lesions. However, few therapeutic measures are effective to prevent or control the severity of acute laminitis and its prodromal stage, which often determines serious complications such as rotation and/or sinking of the distal phalanx and even the loss of hoof. The purpose of this study is to compile the actual knowledge in respect to the pathophysiology and treatment of equine laminitis.

RESUMO: A laminite é uma grave afecção podal, que permanece com fisiopatogenia parcialmente conhecida. Sabe-se que mecanismos isquêmicos, enzimáticos, metabólicos e inflamatórios estão envolvidos no desenvolvimento das lesões laminares. No entanto, poucas medidas terapêuticas são eficazes para prevenir ou controlar a gravidade da laminite nas fases prodrômica e aguda, o que frequentemente determina sérias complicações como rotação ou afundamento da falange distal e até mesmo perda do estojo córneo. O objetivo deste trabalho é compilar os mais atuais conhecimentos sobre a fisiopatologia e tratamento da laminite em equinos.

Systemic leukopenia, evaluation of laminar leukocyte infiltration and laminar lesions in horses with naturally occurring colic syndrome.

The present study was aimed at identifying laminar lesions and leukocyte infiltration in hoof laminar tissue of horses with colic syndrome and its correlation with the total leukocyte count before death. Six healthy horses were used as control group (CG), and eighteen horses with lethal gastrointestinal disease were divided into two groups: leukopenic group (LG) with seven leukopenic horses, and non-leukopenic group (NLG) with 11 horses with total leukocyte count within reference range for the species. Leukocyte infiltration was examined by immunohistochemistry. Laminar lesions were observed in both LG and NLG, with no differences in severity between them. LG showed increase of the leukocyte infiltration in the hoof laminar tissue, when compared to CG and NLG. Horses with severe colic syndrome (LG and NLG) developed intense laminar lesions without clinical signs of laminitis, with increased leukocyte infiltration. However, the LG demonstrated an even higher increase of leukocyte infiltration compared to both CG and NLG.

Relationship between Brazilian Thoroughbred race horses performance and lay-up period after osseous thoracic limb diseases / Relação entre o desempenho e período de recuperação após enfermidades ósseas do membro torácico distal de cavalos Puro Sangue Inglês

It is well established in the literature that musculoskeletal injuries are important compromising agents in the performance of Thoroughbred horses. In Brazil, there are no studies on the interrelation between lay-up period post-injury and retirement of racehorses due to musculoskeletal injures. The aim of this study is to determine the relationship between rehabilitation times of track injures and variables of prior race performance and later return to competitions. The radiographic reports and athletic history of 416 thoroughbreds during the period between 2003 and 2006 were examined; they were selected based on continued presentations after injury diagnosis. The temporal variables (post-injury rehabilitation time) and performance variables (race score before and after injury) were evaluated by multivariate correspondence analysis of the data and represented in perceptual maps. Correspondence was observed between most of the animals that had a short lay-up post-injury and variables that denote decline in subsequent performance. Considering the integrity of the bone healing process as crucial for the horse to be able to handle later training routines and competitions, shortening this period could lead to an imbalance of the bone repair metabolism, thus resulting in performance decline and compromise of the horse athletic career.

Está bem estabelecido na literatura que as lesões músculo-esqueléticas são importantes agentes comprometedores do desempenho em cavalos PSI de corrida. No Brasil, não existem estudos sobre a relação entre o período de reabilitação pós-lesional e o afastamento de cavalos de corridas devido a lesões músculo-esqueléticas. O objetivo deste estudo foi determinar se existe relação entre o tempo de reabilitação de injúrias adquiridas na pista e os resultados obtidos em corridas, antes e depois de retornar às competições. Entre 2003-2006, foram examinados os relatórios radiológicos e história atlética de 416 PSI, selecionados com base em apresentações continuadas após o diagnóstico das lesões. As variáveis temporais (tempo de reabilitação pós-lesão-RT) e variáveis de desempenho (pontuação corrida antes e depois da injúria-SB/SA) foram avaliadas por análise de correspondência multivariada dos dados e representado em mapas de percepção. Correspondência foi observada entre a maioria dos animais que tiveram uma recuperação pós-lesão curta e variáveis que denotam o declínio no desempenho subsequente. Considerando a integridade do processo de cicatrização óssea como crucial para o cavalo a ser capaz de lidar com rotinas de treinamento e competições, o encurtamento deste período poderia levar a um desequilíbrio no metabolismo de reparação óssea, resultando em comprometimento do desempenho e da carreira atlética.

Ausência de efeito antinociceptivo decorrente da administração intravenosa de crotalfina em comparação com morfina, U50-488H ou fenilbutazona em equinos submetidos à estimulação térmica da pele íntegra / Lake of antinociceptive effect caused by intravenous administration of crotalphine em comparision to morphine, U50-488H or phenylbutazone in horses submitted to thermal stimulation of the normal skin

Crotalfina é um novo peptídeo analgésico que atua em receptores opioides kappa e delta promovendo potente analgesia em ratos submetidos a modelos de dor inflamatória, neuropática ou oncológica. Talvez a crotalfina possa ser utilizada para tratar a dor em outras espécies. Assim, o objetivo deste estudo foi avaliar a resposta nociceptiva na região escapular e isquiática de cavalos tratados com crotalfina, morfina, U50-488H ou fenilbutazona e submetidos à estimulação térmica na pele íntegra. Dezoito cavalos da raça Puro Sangue Árabe foram alocados em cinco grupos experimentais: GC (5mL NaCl 0,9%), GCRO (3,8mg.kg-1 crotalfina), GK (160 µg.kg-1 U50-488H), GM (0,1mg.kg-1 morfina) e GF (4,4mg.kg-1 fenilbutazona). Os animais foram submetidos ao modelo de dor inflamatória por meio de estimulação térmica (140°C) e durante 24h avaliou-se a latência para o reflexo do frêmito cutâneo na região escapular (LRFCesc) e isquiática (LRFCisq). O U50-488H apresentou efeito antinociceptivo na região isquiática por duas horas, porém, nos demais momentos do grupo GK, bem como nos grupos GC, GCRO, GM e GF, não foi observado efeito antinociceptivo, visto que a LRFCesc e a LRFCisq na pele íntegra de cavalos não aumentaram em 24 horas de avaliação. Portanto, a crotalfina, a morfina, o U50-488H e a fenilbutazona não produziram efeito antinociceptivo relevante em equinos submetidos à estimulação térmica em pele íntegra.

Crotalphine is a novel analgesic peptide that acts on kappa and delta opioid receptors providing powerful analgesia in rats submitted to inflammatory, neuropathic or oncologic pain model. Maybe crotalphine can be used to treat pain in other species. So, the aim of this study was to evaluate nociceptive response at scapular and isquiatic region of horses treated with crotalphine, morphine, U50-488H or phenylbutazone and submitted to thermal stimulation in complete skin. Eighteen Arabian horses were allocated in five experimental groups: GC (5mL NaCl 0.9%), GCRO (3.8ng.kg-1 crotalphine), GK (160 µg.kg-1 U50-488H), GM (0.1mg.kg-1 morphine) and GP (4.4mg.kg-1 phenylbutazone). Animals were submitted to inflammatory pain model by thermal stimulation (140°C) and during 24h latency to skin twitch at scapular and isquiatic region were evaluated. The U50-488H produced antinociceptive effect at isquiatic region along two hours, but, in other moments of GK and in the other groups there was not antinociceptive effect, because LRFCesc and LRFCisq in complete skin of horses did not increase during 24h evaluation. Thus, crotalphine, morphine, U50-488H and phenylbutazone did not cause relevant antinociceptive effect in horses submitted to thermal stimulation in complete skin.

Expression of matrix metalloproteases-2 and -9 in horse hoof laminae after intestinal obstruction, with or without Hydrocortisone treatment / Expressão de metaloproteinases 2 e 9 no tecido laminar do casco de equinos após obstrução intestinal e tratamento com hidrocortisona

Twenty horses were used in the experiment, for composed control group, (Cg) instrumented group, (Ig;without intestinal obstruction), treated group (Tg;submitted to intestinal obstruction and hydrocortisone treatment) and non-treated group (Ntg;submitted to intestinal obstruction without treatment). Immunohistochemistry and zymography techniques were used for researches on MMPs 2 and 9 in horse hoof laminae. There was an increase in the expression of MMP-2 in animals of Tg and Ntg. MMP-9 increased on animals from groups Ntg and Ig, however there was no rise of this MMP on the Tg when compared to the other groups in the immunohistochemistry analysis. Based on the results, it was observed that the intestinal injury caused by enterotomy and intestinal obstruction raise the quantities of MMPs in the hoof laminae.

Vinte cavalos foram usados no experimento: para compor o grupo controle (Cg), grupo instrumentado, Ig (sem obstrução intestinal), grupo tratado, Tg (submetidos à obstrução intestinal e tratamento com hidrocortisona) e grupo não tratado, Ntg (submetidos à obstrução intestinal, sem tratamento. Técnicas de zimografia e imunoistoquímica foram utilizadas para pesquisa de MMP-2 e MMP-9 no tecido laminar do casco dos equinos. Houve um aumento na expressão de MMP-2 nos animais dos grupos Tg e Ntg. A MMP-9 aumentou nos animais dos grupos Ig e Ntg. Houve aumento desta MMP no Tg quando comparado aos demais grupos na análise por zimografia. Observou-se que a injúria intestinal, causada pela enterotomia e obstrução intestinal, eleva a quantidade de MMPs no tecido laminar do casco.

Efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina, xilazina ou clonidina, em equinos / Behavioral, clinical and antinociceptive effects promoted by pre-emptive epidural injection of morphine, xylazine or clonidine, in horses

Os agonistas dos receptores adrenérgicos 2 e os opioides tem ação analgésica e a aplicação preventiva pela via epidural pode minimizar os efeitos clínicos e comportamentais indesejáveis. Assim, avaliaram-se os efeitos comportamental, clínico e analgésico promovidos pela injeção epidural preventiva de morfina (0,1mg kg-1), xilazina (0,17mg kg-1) ou clonidina (3µg kg-1) durante 24 horas, em 18 equinos submetidos a um modelo incisional de dor inflamatória e avaliados pelos filamentos de von Frey. As alterações comportamentais, de frequência cardíaca, frequência respiratória, temperatura retal e altura de cabeça em relação ao solo foram mínimas e transitórias. A sensibilidade cutânea em pele incisada foi semelhante à sensibilidade da pele íntegra por 24, 8 e 12 horas após a administração epidural preventiva de morfina, xilazina ou clonidina, respectivamente, em equinos submetidos ao modelo incisional de dor inflamatória e avaliados com filamentos de von Frey. Além disso, não ocorreram alterações clínicas ou comportamentais importantes ao longo de 24 horas.

Opioids and 2-agonists have analgesic effect and preventive administration by epidural route can minimize undesirable and clinical effects. So, behavioral, clinical and analgesic effects were evaluated for 24 hours after preventive epidural injection of morphine (0,1mg kg-1), xylazine (0,17mg kg-1) or clonidine (3µg kg-1) in 18 horses subjected to incisional model of inflammatory pain evaluated by von Frey filaments. Behavioral changes and changes in heart rate, respiratory rate, rectal temperature and height of head were minimum and transitory. Cutaneous sensivity in injured skin was similar to complete skin for 24, 8 and 12 hours after preventive epidural injection of morphine, xylazine and clonidine, respectively. Moreover, clinical and behavioral changes were not severe along 24 hours.

The improvement of the anti-hyperalgesic effect of ketamine and of its isomers by the administration of ifenprodil.

Intrathecal or epidural administration of NMDA (N-methyl-D-aspartate) receptors antagonists, in special ketamine and ifenprodil are used to control moderate to severe hyperalgesia in humans. Activation of NMDA receptor usually requires binding of two agonists, glutamate and glycine, in different receptor subunits. Ketamine is a NMDA receptor antagonist and acts at phencyclidine site in NR1 subunit while ifenprodil is a selective NR2B subunit antagonist of NMDA receptor. The aim of this study was to investigate the pharmacological interactions between ketamine or its isomers and ifenprodil, when intrathecally co-administrated, to reduce prostaglandin E(2)-induced hyperalgesia in rat's hind paw. The intrathecal administration of ketamine, its isomers R(-) or S(+), or ifenprodil-induced anti-hyperalgesic effects in a dose-related manner. Ifenprodil, in a dose that did not induce significant effect when administrated alone, significantly improved the anti-hyperalgesic effect of ketamine or its isomers. The other way round, ketamine or S(+) ketamine, but not R(-) ketamine, in a dose that did not induce significant effect when administrated alone, improved the anti-hyperalgesic effect of ifenprodil. However, by comparing ED(50)s (half maximal effective doses), ifenprodil-induced potentiation of ketamine was significantly greater than ketamine-induced potentiation of ifenprodil. The findings of this present study suggest that intrathecal administration of very small doses of ifenprodil, just before and ketamine significantly improves its anti-hyperalgesic effect and this association could be useful to control inflammatory pain with less undesirable effects.

Anestesia por isofluorano em eqüinos submetidos à infusão contínua de medetomidina ou xilazina / Isoflurane anesthesia in horses during medetomidine or xilazine continuous infusion

Avaliaram-se oito eqüinos sob anestesia geral inalatória com isofluorano (1CAM) e infusão contínua de xilazina (0,35mg kg-1h-1) ou medetomidina (3,5µg kg-1h-1), em relação à freqüência cardíaca, ritmo cardíaco, freqüência respiratória, pressão arterial, hemogasometria arterial e temperatura, nos tempos T0 (imediatamente antes do início da infusão contínua) e T10 ao T60 (intervalos de 10 minutos, após início da infusão contínua). Houve redução da freqüência cardíaca e da temperatura e elevação da pressão arterial média. A paCO2 (no GM) elevou-se e a paO2 mostrou-se maior no GM que no GX. Conclui-se que a infusão contínua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatória, com isofluorano, em eqüinos, promove alterações cardiocirculatórias, respiratórias, térmicas e hemogasométricas discretas e equivalentes.

Eight horses under inhalant general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg kg-1h-1) or medetomidine (3.5µg kg-1h-1) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60). Heart rate and temperature decreased and mean arterial pressure increased. PaCO2 (in GM) increased and GM showed a higher paO2 than GX. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalant general anesthesia with isoflurane in horses promote slight and equivalent cardiocirculatory, respiratory, thermic and arterial blood gases changes.

Injeção epidural preventiva de xilazina ou amitraz em eqüinos: efeitos clínicos e comportamentais / Pre-emptive epidural injection of xylazine or amitraz, in horses: clinical and behavioral effects

A xilazina é o fármaco agonista adrenérgico α2 mais utilizado pela via epidural de eqüinos e sabe-se que o amitraz tem ação sobre esses receptores. Assim, foram avaliados os efeitos clínicos e comportamentais causados pela injeção epidural de 0,17mg kg-1 de xilazina (GX) ou de 0,1mg kg-1 de amitraz diluído em emulsão lipídica (GA) durante 24 horas, em doze eqüinos. A freqüência cardíaca e a altura de cabeça mantiveram-se inalteradas; a freqüência respiratória aumentou de T105 a T360 no GX; a temperatura retal elevou-se de T120 a T720 em GA e de T360 a T720 em GX. Não houve diferença no tempo de latência para urinar ou defecar em ambos os grupos. Em relação às alterações comportamentais, o amitraz provocou sedação (50 por cento), ptose labial (33,4 por cento) e palpebral (16,7 por cento), enquanto que a xilazina promoveu ataxia (50 por cento), sudorese perineal (33,4 por cento), ptose palpebral (16,6 por cento) e relaxamento do esfíncter anal (16,6 por cento). Considera-se segura a injeção epidural de xilazina ou amitraz em eqüinos, pois as alterações clínicas e comportamentais promovidas são leves e não limitam seu uso.

Xylazine is the α2-adrenergic agonist more employed by epidural route in horses and it is known that amitraz acts on these receptors. So, clinical and behavioral effects caused by epidural injection of 0.17mg kg-1 xylazine (GX) or 0.1mg.kg-1 amitraz diluted in lipidic emulsion (GA) were evaluated in 12 horses. Heart rate and height of the head didn't change; respiratory rate increased from T105 to T360 in GX; rectal temperature increased from T120 to T720 in GA and from T360 to T720 in GX. There is no difference in latency to urine or defecate in both groups. Concerning behavioral changes, amitraz promoted sedation (50 percent), lip (33.4 percent) and eye (16.6 percent) dropping, while xylazine caused ataxia (50 percent), perineal sweating (33.4 percent), eye dropping (16.6 percent) and anal sphincter relaxation (16.6 percent). So, epidural injection of xylazine or amitraz was considered safe because the clinical and behavioral changes observed are subtle and don't limit its application.

Injeção epidural preventiva de xilazina ou amitraz, em eqüinos: efeito antinociceptivo / Pre-emptive epidural injection of xylazine or amitraz, in horses: antinociceptive effect

Os agonistas de receptores adrenérgicos α2 geram efeito antinociceptivo após administração epidural e o amitraz possui atividade intrínseca sobre tais receptores. Assim, avaliou-se o efeito antinociceptivo promovido pela injeção epidural preventiva de 0,17mg kg-1 de xilazina (GX) ou 0,1mg kg-1 de amitraz diluído em emulsão lipídica (GA) durante 24 horas, em doze eqüinos submetidos a modelo incisional de dor inflamatória e avaliados com filamentos de von Frey quanto ao limiar nociceptivo à estimulação mecânica (LNEM). A xilazina produziu manutenção do LNEM por até 4 horas, enquanto que o amitraz diluído em emulsão lipídica foi capaz de manter o LNEM inalterado por até 24 horas.

Epidural administration of α2 agonists promotes antinociceptive effect and amitraz acts on α2 receptors. Antinociceptivo effect caused by pre-emptive epidural injection of 0.17mg kg-1 xylazine (GX) or 0.1mg kg-1 amitraz diluted in lipidic emulsion (GA) were evaluated, in 12 horses submitted by incisional model of inflammatory pain and evaluated about nociceptive threshold by mechanical stimulus (NTMS), by von Frey filaments. Xylazine produced maintenance of NTMS for 4 hours, while amitraz diluted in lipidic solution maintained NTMS for 24 hours.

Avaliação hemodinâmica e metabólica da cetamina e cetamina S(+) após a reposição volêmica com hidroxietilamido 130/0,4 e solução salina hipertônica 7,5 por cento / Hemodynamic and metabolic evaluation of ketamine and S(+) ketamine after volemic expansion with hydroxyethyl starch 130/0.4 and hypertonic saline solution

O objetivo deste estudo foi avaliar os efeitos hemodinâmicos e metabólicos, após a administração de solução salina hipertônica (NaCL) 7,5 por cento ou em associação ao hidroxietilamido (HES), em cães com hipovolemia induzida e tratados com cetamina. Após a indução da hipovolemia, administrou-se NaCl 7,5 por cento (4,0ml kg-1) no grupo hipertônica levógira (GHL) e grupo hipertônica racêmica (GHR) ou HES 130/0,4 na mesma proporção de sangue retirado, associado a NaCl 7,5 por cento (4ml kg-1) no grupo hipertônica colóide levógira (GHCL) e no grupo hipertônica colóide racêmica (GHCR). Após 30 minutos, administrou-se, por via IV, cetamina levógira (CL) (5mg kg-1) no GHL e GHCL ou cetamina racêmica (CR) (10mg kg-1) no GHR e GHCR. Empregou-se a análise de variância de uma única via com repetições múltiplas (ANOVA) e o teste de Student Newman Keuls (P ≤ 0,05). A frequência cardíaca e a pressão arterial sistólica foram menores após a hipovolemia e após a CR. As pressões arteriais média e diastólica foram menores após a hipovolemia e cetamina. A pressão venosa central foi maior após a administração do colóide. Os índices cardíaco e sistólico foram menores após a hipovolemia em todos os grupos e, após a fase de expansão no GHL e GHR. A pressão média da artéria pulmonar foi menor após a hipovolemia em todos os grupos. A pressão de oclusão da artéria pulmonar foi maior após o colóide. O índice do trabalho ventricular esquerdo foi menor após a hipovolemia no GHCL e GHCR. O índice da resistência periférica total foi maior após a hipovolemia e menor após a CL. Observou-se acidose metabólica após a hipovolemia e após a cetamina. Ocorreu acidose respiratória após a cetamina no GHL e GHR. Conclui-se que a administração de NaCl 7,5 por cento associado ao HES 130/0,4 promove o restabelecimento imediato dos parâmetros hemodinâmicos e metabólicos no paciente hipovolêmico; a administração isolada de NaCl 7,5 por cento não é capaz...

The objective of this study was to evaluate the hemodynamics and hemogasometrics effects, after the administration of hypertonic solution (NaCl 7.5 percent) or in association with hidroxyethyl starch 130/0.4 (HES), in dogs with induced experimental hypovolemia and treated with racemic ketamine (RK) or S(+) ketamine (SK). After the hypovolemia induction, administration of NaCl 7.5 percent (4 ml kg-1) was performed in two groups called hypertonic S(+) group (HSG) and hypertonic racemic group (HRG), or NaCl 7.5 percent (4 ml kg-1) in association with HES, in the same ratio of removed blood, in two groups called hypertonic colloid S(+) group (HCSG) and hypertonic colloid racemic group (HCRG). After 30 minutes, it was administered by intravenous injection, SK (5tymg kg-1) in HSG and HCSG groups, or RK (10 mg kg-1) in HRG and HCRG groups. To evaluate the significance of the results, it was used One-way Analysis of variance (ANOVA) for repeated measures and Student Newman Keuls method (P ≤ 0.05). The heart rate and the systolic arterial pressure were reduced after hypovolemia and administration of the RK. Mean and diastolic arterial pressure were reduced after hypovolemia and either SK or RK administration. The central venous pressure was increased after administration of the colloid. The cardiac output, index cardiac, and index systolic were reduced after hypovolemia in all groups and, after phase of expansion in HSG and HRG. The pulmonary arterial occlusion pressure was increased after colloid administration. The left ventricular work index was reduced after hypovolemia in HCSG and HCRG. The systemic vascular resistance index was increased after hypovolemia and decreased after administration of the SK. The CO2 concentration to the end of the expiration increased after administration of ketamine in HCSG and HCRG. Metabolic acidosis was observed after hypovolemia and after administration of ketamine in all...

Comparison of the effects of romifidine and an emulsion of amitraz on sedation and spontaneous locomotor activity of horses / Comparação dos efeitos da romifidina e de uma emulsão de amitraz na sedação e na atividade locomotora espontânea de eqüinos

Amitraz (AM) and romifidine (RMF), two alpha-2 adrenoceptor agonists, produce sedative effect and decrease spontaneous locomotor activity (SLA) of horses. The behavioral effects and sedation after intravenous injection of RMF (0.06mg/kg) or AM 0.1mg/kg (AM 0.1) or AM 0.4mg/kg (AM 0.4) were compared in horses. RMF caused head ptosis (HP) until 45 min. The lower AM dose induced HP from 45 to 60 minutes and from 120 to 150 minutes, and the higher dose induced HP until 180 minutes. Data concerning changes in SLA were not conclusive. RMF or AM 0.4 caused a greater sedation than AM 0.1 until 20 min. After 20 minutes, the sedation caused by AM 0.4 was greater than that of RMF or AM 0.1. Romifidine caused consistent sedation until 45 minutes. The amitraz emulsion produced a dose-dependent sedation until 180 minutes. Comparing to romifidine, the emulsion of amitraz induced a more substantial sedation. At dosages and dilution applied, amitraz is an effective sedative for horses.

Os agonistas de receptores adrenérgicos do tipo alfa-2 amitraz (AM) e romifidina (RMF) produzem efeito sedativo e reduzem a atividade locomotora espontânea (ALE) em eqüinos. Compararam-se os efeitos sedativos e comportamentais da injeção intravenosa de RMF (0,06mg/kg) ou AM 0,1mg/kg (AM 0,1) ou 0,4mg/kg (AM 0,4) em cavalos. RMF provocou ptose de cabeça (PC) por 45 minutos. O amitraz provocou PC entre 45 e 60 e entre 120 e 150 minutos com a dose menor, e por 180 minutos com a dose maior. Os dados relacionados à ALE não foram conclusivos. RMF ou AM 0,4 causaram sedação mais intensa que AM 0,1 até 20 minutos. Após 20 minutos, a sedação provocada pelo AM 0,4 foi mais intensa que para a RMF ou o AM 0,1. A romifidina causou sedação por 45 minutos. A emulsão de amitraz provocou sedação dose-dependente por 180 minutos. Em relação à romifidina, o amitraz produziu uma sedação mais consistente. Nas doses e na diluição aplicada, o amitraz é eficaz como sedativo para cavalos.

Preemptive effects of epidural s (+) - ketamine ketamine in the horse's postincisional pain

The aim of this study was to evaluate the pre-emptive effect of epidural ketamine S (+) (SK) or racemic ketamine (RK) admirustration, in post-incisional pain in horses. Were used in a blinded, randomized experimental study, sixteen mixed breed mares, 6±2 years old, weighting 273.2±42.0 kg. An epidural catheter was inserted 24 hours before the trials. The thigh region was shaved bilaterally, and mechanical cutaneous sensibility was measured using von Frey filaments (T-30). U sing the left side as the control one, local anesthesia was performed at the right side. Twenty-five minutes later, SK was injected in G 1 or RK in G2 through the epidural catheter. Five minutes after the ketamine injection, a 10 cm skin incision was made on the right side, and then sutured. Mechanical post-incisional pain was measured using von Frey filaments, at 1,3 and 5 cm around the incision at 15 minutes intervals, for 2 hours, then 4, 6 and 8 hours after suturing. No changes were observed in the heart and respiratory rate and rectal temperature among groups or times of each group. Hind limb ataxia was observed in 62.5% and 12.5% of G 1 and G2 respectively. SK and RK reduced cutaneous sensibility in the right and the left sides to mechanical postincisional pain during all time of experiment. Epidural SK and RK produce similar post - incisional analgesic effects, did not interfere in the cardio-respiratory parameters. The SK induces more intense ataxia in mares and presents a larger analgesic potency in the first 60 minutes after the administration.

O objetivo deste estudo foi avaliar o efeito analgésico da administração prévia de cetamina S (+) ou cetamina, na dor pós-inciosal em eqüinos. Utilizaram-se, em um estudo duplo-cego ao acaso, 16 éguas com idade de 6±2 anos, pesando 273,2±42,0 kg. 24 horas antes do início do experimento introduziu-se um cateter epidural. No dia seguinte, as regiões isquiáticas direita e esquerda foram tricotomizadas e, a sensibilidade cutânea aferida utilizando-se os filamentos de Von Frey, tempo -30 (T-30). Realizou-se bloqueio anestésico em linha, no lado direito e, 25 minutos após administrou-se através do cateter epidural cetamina S(+) no G 1 e cetamina no G 2. Cinco minutos após a injeção de cetamina, realizou-se uma incisão de pele de 10 cm no lado direito, seguida de sutura. Avaliou-se a dor pós-incisional, utilizando-se os filamentos de Von Frey, a 1, 3 e 5 cm ao redor da incisão (lado incindido) e a sensibilidade cutânea (lado controle), em intervalos de 15 minutos, por 2 horas e então, 4, 6 e 8 horas após a sutura de pele. Não foram observadas alterações nas freqüências cardíaca ou respiratória e temperatura retal entre os grupos ou entre os tempos de cada grupo. Observou-se ataxia de membros pélvicos em 62,5% e 12,5% dos animais, para o G 1 e G2, respectivamente. A cetamina S(+) e cetamina reduziram a sensibilidade cutânea no lado direito e esquerdo, para os estímulos mecânicos produzidos pelos filamentos de Von Frey, durante todo os período experimental. A cetamina S(+) e cetamina produziram duração de efeito analgésico similares e não interferiram nos parâmetros cardiorrespiratórios. Observou-se ataxia mais intensa e potência anestésica superior nos primeiros 60 minutos após a administração de cetamina S(+).

Características do líquido peritoneal de eqüinos normais após punção cecal percutânea / Peritoneal fluid characteristics in normal horses after percutaneous cecal trocharization

Foram avaliados 10 eqüinos da raça Manga Larga, machos, inteiros clinicamente sadios, submetidos à punção cecal percutânea. Analisou-se a resposta clínica, celular, bioquímica e microbiológica do líquido peritoneal por um período de 24 horas após a punção cecal, nos tempos T0, T6, T12 e T24. Foi observada elevação na freqüência respiratória em T6 e na temperatura retal entre T6 e T12. Decorridas 24 horas da punção cecal, ocorreu aumento na concentração de proteínas totais do líquido peritoneal e na atividade da fosfatase alcalina. Tanto a atividade da ALT quanto os níveis de hemoglobina apresentaram diminuição em T6. Não foram registradas alterações na celularidade do plasma ou do líquido peritoneal e obteve-se resultado negativo para a cultura microbiológica do líquido. Considerando a inexistência de efeitos adversos, além das poucas alterações descritas, conclui-se que a punção cecal percutânea é um procedimento seguro e factível, se praticada criteriosamente.

Timpanismo bilateral de bolsa gutural em potro / Bilateral tympany of a guttural pouch in foal

Uma potra da raça Quarto de Milha com dois meses de idade apresentava aumento de volume bilateral na região da parótida desde algumas horas após o nascimento. Por exame radiográfico diagnosticou-se timpanismo bilateral de bolsa gutural. Realizou-se a abertura cirúrgica da bolsa gutural esquerda e fenestrou-se o septo medial das bolsas guturais. Adicionalmente, procedeu-se à ressecção parcial da mucosa na abertura do orifício guturo-faríngeo. A afecção foi debelada, sem recidivas.