Thiopental alters long term nociceptive response of young rats

The objective of this study was to evaluate the long term nociceptive response determined by use of two general anesthetics, one intravenous and the other inhalatory, in young animals. In the first experiment, the animals of 21 days of age were divided into control (saline) and thiopental (35 mg/kg, i.p.) groups. In the second experiment, rats of the same age were divided in two groups – halothane (2%) and control. In experiment 1, there was difference between groups – reduction of tail-flick latency in the group thiopental (P< 0.05). In experiment 2, there were no differences between groups or interaction between time versus group (F(1,19)=0.11 for groups, P>0.05; F(1,19)=0.032 for the interaction, P>0.05). The results obtained in this study showed that halothane did not alter the nociceptive response in young animals. However, the thiopental induced hyperalgesic response in rats.Key words: Rats. Sodium thiopental. Halothane. Nociception. Tail flick latency. RESUMO O objetivo desse estudo foi avaliar a resposta nociceptiva a longo prazo relacionada ao uso de dois anestésicos gerais – um intravenoso e outro inalatório, em animais jovens. No primeiro experimento, os animais de 21 dias de idade foram divididos nos grupos controle (solução salina) e tiopental sódico (35 mg/kg, i.p.). No segundo experimento, animais de mesma idade foram divididos em dois grupos – halotano (2%) e controle. No Experimento 1, houve redução da latência de retirada da cauda no grupo tiopental (P0,05; F(1,19)=0,032 para a interação, P>0,05). Os resultados obtidos nesse estudo demonstraram que o halotano não altera a resposta nociceptiva em animais jovens. Entretanto, o tiopental induziu resposta hiperalgésica nestes ratos.Palavras-chave: Ratos. Tiopental sódico. Halotano. Nocicepção. Latência de retirada da cauda.