Tratamento neonatal com agonista 5-HT1A: repercussÃes sobre o desenvolvimento da atividade locomotora em ratos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Locomotion is an important function to living beings. Environmental changes that occur during the critical period of development can promote changes in the development of locomotor activity, bringing impairment for the individual. Works using automatic analysis of behavior are of great importance for the study of locomotion. Among the systems that can influence the development of locomotor activity is serotonergic system. It is suggested that its action is mediated via 5-HT1A receptors. This thesis aimed to study the effects of pharmacological manipulation, chronic or acute, with 5-HT1A partial agonist, on locomotor activity, in rats. In the first study, we developed an automated system for the analysis of locomotor activity of small animals, subjected to an open field. This system allows the study of locomotor activity verifying if adverse environmental stimuli may alter locomotor pattern. Covered distance, average velocity, average potency, immobility time, number of stops, time the rat spent in the different areas of the open field and immobility time/number of stops relationship were the studied parameters Validation of this system occurred by the analysis of the locomotor development in normal rats. 19 male Wistar rats were used, and studied at the 8th, 14th, 17th, 21st, 30th and 60th postnatal days, during 2 minutes. The system proved to be able to effectively extract the desired parameters. Thus it was possible to observe changes in the pattern of locomotion of animals, due to its development. In the second study, buspirone was administered chronically, from the 1st to the 21st postnatal day, subcutaneously, in doses of 2.5 (n = 13), 5 (n = 13) and 10 (n = 13) mg/Kg, in rats. In control animals was administered saline (n = 14). 53 male Wistar rats were used. System used, ages and parameter evaluated were the same at the first study. Neonatal treatment reduced the average potency, at 60 days, in all doses used. It also changed evolution of characteristic of the number of stops and immobility time/number of stops relationship, at lowest doses, during development. In those animals submitted to neonatal handling, acute application of buspirone (5 mg/Kg) was made, at 70 days, and 30 minutes after administration, the locomotion was measured for 10 minutes. In all animals, locomotor activity was decreased, indicating a possible drug sedative effect. Noteworthy, we observed a reduction of covered distance and number of stops, and increased time of immobility. However, the group that received the highest dose of buspirone, during lactation, the reduction in covered distance was lower. In sum, neonatal administration with buspirone changes some parameters of locomotor activity. Acute administration of buspirone reduces locomotion. Nevertheless, at lower intensity in animals treated with the highest dose of the drug, during lactation, suggesting occurrence phenomenon of programming.

ASSUNTO(S)

neurologia atividade locomotora automatic analysis of locomotion development open field programming anÃlise automÃtica da locomoÃÃo desenvolvimento programaÃÃo rats campo aberto locomotor activity buspirona ratos serotonin serotonina buspirone

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