LUZ, MELATONINA E ESTRESSE OXIDATIVO NA PISCICULTURA

In fish, as in mammals, parts of the nervous system are involved in mechanisms for regulation of body systems in harmony with the environment. The photoperiod is translated into physiological information from melatonin secretion. There seems no morphological and physiological hurdles for this indoleamine, i.e., melatonin quickly into perfuses every cell of the body and in some cases membrane and interacts with receptors locate don’t he cell surface and appears to be related to food in take, growth and locomotion fish. Molecules are important metabolizing reactive oxygen species to in active products and thus reducing oxidative damage. This work aims to give a brief survey of recent articles about light, melatonin and oxidative stress in fish, and correlates them with fish farming. We conclude that the light appears to be linked to the production of melatonin, and this antioxidant molecule, which favors the reduction of oxidative stress, seem to improve performance in fish production.Keywords: Melatonin; oxidative stress; pisciculture.Em peixes, como nos mamíferos, partes do sistema nervoso estão envolvidas em mecanismos para regulação dos sistemas corporais em sintonia com o meio. O fotoperíodo é traduzido em informações fisiológicas a partir da secreção de melatonina.Parece não haver barreiras morfofisiológicas para esta indolamina, isto é, a melatonina perfunde-se rapidamente em cada célula do organismo e em alguns casos interage com receptores e membrana situados na superfície celular, e parece estar ligada à ingestão de alimentos, crescimento e atividade locomotora de peixes. São moléculas importantes metabolizando espécies reativas de oxigênio a produtos inativos e, portanto, reduzindo o dano oxidativo.Este trabalho tem por objetivo fazer um breve levantamento em artigos recentes sobre luminosidade, melatonina e o estresse oxidativo em peixes, e correlaciona-los com piscicultura. Concluímos que a luminosidade parece estar ligada a produção de melatonina, e esta molécula antioxidante, que favorece a redução do estresse oxidativo, parecem melhorar o desempenho na produção de peixes em criadouros.Palavras-chave: Melatonina, estresse oxidativo, piscicultura

Matters concerning sound perception of harmonics: the function of the sex and apprenticeship variables

The aim of this study was to verify the performances of men and women in a discriminative test of sound harmonics perception, and the effect of prior learning on this discrimination. The experiment was conducted using 17 men and 17 women, who were individually submitted to an experimental session with a standard questionnaire and a sound perception test comprising 20 attempts recorded on a CD-ROM. The statistical analysis of the data shows that subjects, both with and without experience of learning a musical instrument, have a difference in performance in the test [F(1.33) = 14.69, p<0.001]. Though not significant, women displayed a better performance in the group without learning, and in the group with experience, men showed better performance. The data show that, though there may be differences between the genders in terms of sound perception, previous experience is ostensibly the most important factor in this type of discrimination.Este trabalho objetivou verificar o desempenho de homens e mulheres em uma tarefa de discriminação perceptiva de sons e o efeito de aprendizagem anterior sobre esta discriminação. O experimento foi realizado com 17 homens e 17 mulheres, submetidos individualmente a uma sessão de coleta de dados composta de questionário padronizado e de teste de discriminação com vinte tentativas gravadas em um CD-ROM. A análise estatística dos dados indicou diferenças de desempenho entre pessoas com e sem experiência musical prévia [F(1,33)=14,69, p<0,001]. Embora não significativo, as mulheres apresentaram melhor desempenho no grupo sem experiência prévia, e no grupo com experiência, os homens apresentaram melhor desempenho. Os dados indicam que, embora haja diferenças sexuais na percepção sonora, a experiência parece ser o fator mais importante neste tipo de discriminação

Subchronic effects of fluoxetine on conditioned suppression produced by a hot air blast

Conditioned suppression is an animal model of anxiety disorders that has been broadly used to investigate the behavioral effects of different drugs. However, various methodological variables (e.g., the type of aversive stimulus) that supposedly interfere with the acquisition of conditioned suppression may also contribute to conflicting results among the studied drugs. Additionally, few studies have sought to investigate the effects of selective serotonin reuptake inhibitors (SSRIs). The present study investigated the effect of subchronic 5-day administration of 5 mg/kg fluoxetine in the retention of conditioned suppression produced by a hot air blast (HAB). The subjects were 12 albino Wistar rats distributed into an Experimental Group (EG) and Control Group (CG). After sessions were conducted to pair two stimuli, a sound and HAB, fluoxetine (EG) or saline (CG) was administered. Twentyfour hours after the last injection, a test session was conducted. The results showed no difference between groups. Fluoxetine (5 mg/kg) did not exert anxiolytic effects in this model of conditioned suppression produced by a HAB. Keywords: conditioned suppression; fluoxetine; subchronic; hot air blast