The inhibition of osmotic stimulated water flow in the isolated toad bladder by 0.1 mM sodium stibogluconate (pentavalent antimony) is described. Pentavalent antimony on the serosal surface significantly inhibited oxytocin-induced water flow but when the drug was added to the mucosal surface only the effect of low oxytocin concentrations was reduced. The phosphodiesterase inhibitor pentoxifylline, when present on the serosal side, blocks the effect of pentavalent antimony on stimulated water flow. No effect was detected when indomethacin was present on the serosal side. It is suggested that phosphodiesterase activation might play a role in the mechanism of pentavalent antimonial inhibition of oxytocin-induced water flow in the isolated toad bladder. The effect obtained when sodium stibogluconate on the serosal side was replaced with antimony pentachloride (SbCl5) supports the view that the metal in the molecule is responsible for the inhibition of the effect of oxytocin.
Animals Antimony Sodium Gluconate