ABSTRACT
It is known that chronic high levels of corticosterone (CORT) enhance aversive responses such as avoidance and contextual freezing. In contrast, chronic CORT does not alter defensive behavior induced by the exposure to a predator odor. Since different defense-related responses have been associated with specific anxiety disorders found in clinical settings, the observation that chronic CORT alters some defensive behaviors but not others might be relevant to the understanding of the neurobiology of anxiety. In the present study, we investigated the effects of chronic CORT administration (through surgical implantation of a 21-day release 200 mg pellet) on avoidance acquisition and escape expression by male Wistar rats (200 g in weight at the beginning of the experiments, N = 6-10/group) tested in the elevated T-maze (ETM). These defensive behaviors have been associated with generalized anxiety and panic disorder, respectively. Since the tricyclic antidepressant imipramine is successfully used to treat both conditions, the effects of combined treatment with chronic imipramine (15 mg, ip) and CORT were also investigated. Results showed that chronic CORT facilitated avoidance performance, an anxiogenic-like effect (P < 0.05), without changing escape responses. Imipramine significantly reversed the anxiogenic effect of CORT (P < 0.05), although the drug did not exhibit anxiolytic effects by itself. Confirming previous observations, imipramine inhibited escape responses, a panicolytic-like effect. Unlike chronic CORT, imipramine also decreased locomotor activity in an open field. These data suggest that chronic CORT specifically altered ETM avoidance, a fact that should be relevant to a better understanding of the physiopathology of generalized anxiety and panic disorder.
Subject(s)
Animals , Male , Rats , Antidepressive Agents, Tricyclic/administration & dosage , Anxiety/drug therapy , Behavior, Animal/drug effects , Corticosterone/administration & dosage , Imipramine/administration & dosage , Panic Disorder/drug therapy , Antidepressive Agents, Tricyclic/pharmacology , Corticosterone/pharmacology , Escape Reaction/drug effects , Imipramine/pharmacology , Maze Learning/drug effects , Motor Activity/drug effects , Rats, WistarABSTRACT
A medida da forca de preensao palmar tem sido um dos meios uteis para a avaliacao das caracteristicas fisicas, a evolucao durante a reabilitacao e o grau de incapacidade. Na pratica clinica o fisioterapeuta se depara com a dificuldade em selecionar o protocolo mais adequado e eficiente para o fortalecimento muscular. O objetivo deste trabalho foi comparar dois protocolos de regimes isotonicos buscando evidenciar qual deles seria o mais indicado para o fortalecimento musculos responsaveis pela preensao. As medidas da forca de preensao pre e pos-treinamento foram realizadas com um dinamometro mecanico da marca Jamar, em 22 mulheres com idade entre 18 e 21 anos (media de 19 anos). As voluntarias foram separadas em 2 grupos, DeLorme (carga crescente) e Oxford (carga decrescente), para a aplicacao dos protocolos. Para o treinamento foi utilizado um exercitador de mao e dedos da marca Digi-flex, e o programa foi realizado duas vezes por semana, com duracao de 20 minutos cada sessao em um total de 8 sessoes. Posteriormente, foram comparadas as forcas pre e pos-treinamentos e foi observado que, para as amostras dependentes (pre e pos-treinamentos), houve diferenca significativa tanto no grupo DeLorme quanto no Oxford, ja para as amostras independentes (pos-DeLorme e pos-Oxford) nao houve diferenca significativa
Subject(s)
Disability Evaluation , Physical Education and Training , Physical Therapy Specialty , RehabilitationABSTRACT
The zebrafish (Danio rerio) has been used as a model in neuroscience but knowledge about its behavior is limited. The aim of this study was to determine the preference of this fish species for a dark or light environment. Initially we used a place preference test and in a second experiment we applied an exit latency test. A two-chamber aquarium was used for the preference test. The aquarium consisted of a black chamber and a white chamber. In the first experiment the animal was placed in the aquarium and the time spent in the two compartments was recorded for 10 min. More time was spent in the black compartment (Wilcoxon matched-pairs signed-rank test, T = 7, N1 = N2 = 18, P = 0.0001). In the second experiment the animal was placed in the black or white compartment and the time it took to go from the initial compartment to the opposite one was recorded. The test lasted a maximum of 10 min. The results showed that the animal spent more time to go from the black to the white compartment (Mann-Whitney rank sum test, T = 48, N1 = 9, N2 = 8, P<0.0230). These data suggest that this fish species has a natural preference for a dark environment and this characteristic can be very useful for the development of new behavioral paradigms for fish.