Tiopental bloqueia os canais de K+apt nas células B pancreáticas
Palavras-chave:
célula B, efluxo de 86Rb, tiopental, ilhotas de LangerhansResumo
Objetivo
Este trabalho estuda o efeito do tiopental sobre a permeabilidade ao K* em ilhotas de Langerhans, isoladas de ratos
Métodos
As ilhotas foram isoladas pelo método da colagenase, marcadas durante 90 minutos com 8'RbCI (substituto de K*) e perfundidas em solução de Krebsbicarbonato em diferentes condições experimentais.
Resultados
Os resultados indicam que o tiopental (0,2 e 2,OmM) reduziu o efluxo de 86Rb de ilhotas perfundidas, tanto na presença quanto na ausência de gIIcose, em solução contendo ainda 20 ou 100Kg/ml de tolbutamida. que é um bloqueador dos canais de K* modulados pelo ATP. O efeito inibidor de tÊopental no efluxo do 86Rb foi mais notável quando a perfusão das ilhotas foi processada em solução contendo diazoxida, substância que abre os canais de K* modulados pelo ATP.
Conclusão
Com base em resultados obtidos em experimentos com sulfoniluréias, constatou-se que o tiopental atua bloqueando preferencialmente, de maneira dose-dependente e reversível, os canaÉs de K* modulados pelo ATP.
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