Blood lactate threshold reflects glucose responses in horses submitted to incremental exercise test / Limiar sangüíneo de lactato reflete a resposta da glicose em cavalos submetidos a teste de exercício progressivo

Determinou-se, em eqüinos, o efeito do treinamento sobre as concentrações sangüíneas de lactato e plasmáticas de glicose durante exercício de intensidade progressiva em esteira rolante. Demonstrou-se que o treinamento aeróbico causou diminuição da concentração máxima de lactato e que o limiar de lactato corresponde ao ponto de inflexão da curva de glicose plasmática, confirmando esse parâmetro como indicador da capacidade aeróbica de cavalos.

Composição de fibras musculares esqueléticas de eqüinos jovens da raça Brasileiro de Hipismo / Composition of skeletal muscle fibers of young Brasileiro de Hipismo horse breed

The aim of this study was to typify the skeletal striated fibers of the gluteus medius muscle of young Brasileiro de Hipismo (BH) horses by means of histochemical analysis with m-ATPase and NADH-TR according to the sex and the biopsy depth. It was observed that the frequency (F; percent) and the relative cross sectional area (RCSA; percent) of the fibers type IIX were greater than the fibers type IIA, which F and RCSA were greater than the fibers type I. The comparison between sex and muscles depht, showed no significant difference in F and RCSA in the three types of fibers. The results of morphometry showed that the gluteus medius muscle has greater glycolitic metabolism and anaerobic capacity because of the presence of large proportion of type IIX fibers. This may be justified by the genetic influence of Thoroughbred in the formation of Brasileiro de Hipismo breed.

Comparative study of the sedative and antinociceptive effects of levomepromazine, azaperone and midazolam in laboratory animals

Os efeitos sedativos e antinociceptivos da levomepromazina, azaperone e midazolam foram avaliados utilizando-se três testes de comportamento em ratos e camundongos. No teste da atividade locomotora espontânea em campo aberto observou-se que tanto o comportamento exploratório como a atividade locomotora espontânea foram significativamente diminuídos quando se utilizou levomepromazina e azaperone. O efeito causado pelo azaperone foi menos prolongado quando comparado ao da levomepromazina. O midazolam causou diminuição do comportamento exploratório sem alterar a atividade locomotora espontânea. Quando se avaliou o efeito antinociceptivo por meio da latência para o reflexo da retirada da cauda em ratos após estímulo doloroso, as drogas não apresentaram nenhum efeito antinociceptivo observável. No teste das contorções em camundongos, os fármacos foram capazes de abolir as contorções quando comparados ao efeito do grupo-controle. Levomepromazina, azaperone e midazolam nas doses utilizadas foram capazes de inibir o comportamento exploratório de ratos, comprovando seus efeitos sedativos. Com relação aos efeitos antinociceptivos para dor visceral, eles foram capazes de inibir as contorções.

Toxicological evaluation of long-term intravenous administration of amitraz in horses

With the aim of determining the possible toxicity of amitraz after its prolonged use in horses, six English Thoroughbred horses received intravenous injections of amitraz (0.05, 0.10 or 0.15 mg/kg) weekly for four months, constituting the experimental group. Eight other animals (control group), via the same route following the same drug administration schedule and period of time, received the vehicle, dimethylformamide. At the end of this period, blood was collected from all the animals, and a comparison was made of the means of the values obtained for the various blood analyses: complete hemogram, alkaline phosphatase, gamma-glutamyltransferase, blood urea nitrogen, lactate dehydrogenase, aspartate aminotransferase, creatine phosphokinase, glucose, albumin, total protein, creatinine, Na+ , K+, Cl- and CO2. The results for the biochemical characteristics showed that only the mean value for urea of the animals submitted to treatment with amitraz was significantly different than the mean value obtained for the control group. The analyses of the hematological characteristics showed that no significant differences between groups were observed. Similarly, the measurement of blood electrolyte levels demonstrated that long-term treatment with amitraz did not cause significant changes in the variables analyzed. The results indicate that amitraz, given in the doses employed in this study, did not show signs of inducing toxic effects in vital organs, even after prolonged administration