Biodistribution study of the anaesthetic sodium phenobarbital labelled with technetium-99m in Swiss mice infected with Schistosoma mansoni Sambon, 1907.

Technetium-99m (99m Tc) is a radionuclide that has negligible environmental 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 performed with acetone (solvent). The 99mTc-PBBT was administered by intraperitoneal route to Swiss mice infected eight weeks before. The animals were perfused after different 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.