: Malaria parasite action in the blood marks the clinical stage of malaria. To evaluate the potential effect of dihydroartemisinin on the heart during malaria treatment with oral dihydroartemisinin, we investigated the effect of five dosage regimens of oral dihydroartemisinin (DHA) on the cardiac muscles of the heart of Wistar albino rats. The dosage regimens of DHA administered were 1mg/kg; 2mg/kg; 60mg/kg; 80mg/kg and a dose of 1mg/kg administered twice to the same test rats with a rest period of 1 week in between. These dosage regimens of DHA were administered for 5 days or 7 days. Tissue photomicrographs of the Heart of DHA-treated and control rats showed two types of inhibitory occupation of cardiac muscles by DHA which were a lighter β1 occupation of the myocardium and the walls of the coronary blood vessels which produced a relaxation and calming effect and a heavier β2-adrenoceptor inhibitory effect on haemopoeitic sites around coronary blood vessels which like erythropoietin inhibited DNA cleavage (followed by programmed cell death) and causes erythroid stem cells to survive and develop into mature erythrocytes. This strong inhibitory occupation action of DHA was also present on nodal tissue (sinoartrio and artrio-ventricular nodes) of the heart. The findings of the study suggest that oral dihydroartemisinin produced a gentle β1-adrenoceptor positive ionotropic effect on the myocardium; a β1-adrenoceptor relaxation effect on coronary blood vessels; a β2-adrenoceptor inhibitory effect on erythroid stem cell DNA cleavage / cell apoptosis (promotion of haemopoeisis) and a β2-adrenoceptor inhibitory effect on cardiac nodal tissues The study concludes that oral dihydroartemisinin produced both β1-adrenoceptor and β2-adrenoceptor occupation and activity on the cardiac muscles of Wistar albino rats.
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