Red cells infected with the human
malaria parasite Plasmodium falciparum have an increased permeability to a range of small, structurally unrelated solutes via a
malaria-induced pathway. We report here a similar pathway present in parasitised red cells from chickens infected with the
avian malaria parasite, Plasmodium gallinaceum. Parasitised cells showed a marked increase in the rate of influx of
sorbitol (76-fold) and, to a lesser degree,
taurine (3-fold) when compared with red cells from uninfected chickens. Pharmacological data suggest that both
sorbitol and
taurine are transported via a single
malaria-induced pathway, which is sensitive to inhibition by
5-nitro-2-(3-phenylpropylamino)benzoic acid (IC(50) approximately 7 microM). The
malaria-induced pathway differed in its inhibition by a range of
anion channel inhibitors when compared to the endogenous, volume-activated osmolyte pathway of chicken red cells. There were also differences in the selectivity of
sorbitol and
taurine by the two permeation routes. The data presented here are consistent with the presence of two distinct organic solute pathways in infected chicken red cells. The first is an endogenous volume-activated pathway, which is not activated by the parasite and the second is a
malaria-induced pathway, similar to those that are induced by other types of
malaria in other host species.