Chloroquine effects on parasite and host membranes of intraerythrocytic Plasmodium chabaudi.

Mice infected with Plasmodium chabaudi were treated with 50 mg/kg chloroquine (CQ) ofr 2 hr. Trophozoite-infected erythrocytes from CQ-treated and untreated mice were then compared concerning the structure of both parasite and host membranes by thin-sectioning and especially freeze-etching electron microscopy. Chloroquine induces dramatic alterations in parasite endomembranes. The rough endoplasmic reticulum disappears in about 30-40% of the trophozoites. Concomitantly, local agglomerations of smooth tubular membranes emerge and the nuclear envelope becomes closely apposed by a smooth cisterna. The CQ-treatment, however, apparently does not affect the parasite and host plasma membrane as well as the membrane of the parasitophorous vacuole in terms of membrane width, frequency and distribution of the typical membrane-intercalating-particles, as well as temperature- and Ca2+-response.