Technetium-99m (99mTc) is a radionuclide that has negligible enviromnental impact, is easily available, inexpensive and can be used as a radioactive tracer in biological experiences. In order to know the mode of action of sodium phenobarbital in moving adult Schistosoma mansoni worms from mesenteric veins to the liver, we labelled sodium phenobarbital (PBBT) with 99mTc and a biodistribution study in infected and non-infected Swiss mice was performed. The PBBT was incubated with stannous chloride used as reducing agent and with 99mTc, as sodium pertechnetate. The radioactivity labelling (%) was determined by paper ascending chromatography perfomed with acetone (solvent). The 99mTc-PBBT was administered by intraperitoneal route to Swiss mice infected eight weeks before. The animals were perfused after diferent periods of time (0,1,2,3,4 hr) when blood, spleen, liver, portal vein, mesenteric veins, stomach, kidneys and adult worms were isolated. The radioactivity present in these samples was counted in a well counter and the percentage was determined. The radioactivity was mainly taken up by the blood, kidney, liver and spleen. No radioactivity was found on the adult worms. We concluded that the worm shift was due to an action on the host of the sodium phenobarbital

Comparou-se o efeito de drogas anestésicas na localização de vermes adultos em camundongos albinos. Com 56 dias de infecção os animais foram anestesiados com pentobarbital sódico, éter ou clorofórmio. Imediatamente realizou-se a perfusão, sendo os vermes recolhidos e classificados quanto à localização em fígado ou veia porta e nos vasos mesentéricos. Nossos resultados demonstraram que o pentobarbital sódico produziu maior deslocamento dos vermes para o fígado (89%) do que o éter (76%) e o clorofórmio (34%) quando comparados com o grupo controle (22%). As diferenças para o pentobarbital sódico e o éter foram significativas (P < 0,05). Sugerimos que os anestésicos não sejam utilizados nos estudos sobre a distribuição de vermes adultos nos hospedeiros.

The effect of anesthetic drugs on the localization of adult worms in albino mice was compared. The animals with 56 days of infection were anesthetized with pentobarbital sodium, ether or chlorophorm. Perfusion was carried out immediately after, recovering the worms and classifying them in relation to their localization on the liver or portal vein and the mesenteric veins. Our results showed that pentobarbital sodium produced a greater displacement of the worms to the liver (89%) than ether (76%) and chlorophorm (34%) did, when compared to the control group (22%). The difference between pentobarbital sodium and ether was significant (p < 0.05). We suggest that anesthetic drugs may not be used in studies on the distribution of adult worms in several hosts.