The chemotherapy of rodent malaria, XXI. Action of quinine and WR 122 (a 9-phenanthrenemethanol) on the fine structure of Plasmodium berghei in mouse blood.

The effects of quinine and a 9-phenanthrenemethanol, WR 122,455 on the fine structure of Plasmodium berghei have been investigated. Changes consequent upon quinine treatment were noted in the outer membranes (including those that surround the "food vacuole") and the digestive vacuoles. These changes were followed by cytoplasmic degeneration and vacuolization. WR 122,455 caused morphological changes in at least three areas of the parasite, (1) the outer membranes, (2) the digestive vacuole and (3) the nucleus. The relationship of these changes to the mode of action of these compounds is discussed. It seems possible that they interfere primarily with limiting membrane-mitochondrial functions. The modifications of pigment formation are characteristic of these compounds and differ from those seen with chloroquine or primaquine.