[Accumulation and effluxion of chloroquine in chloroquine-sensitive and chloroquine-resistant Plasmodium berghei].

AIM: To explore whether the difference in the amount of chloroquine (CQ) accumulated in CQ-resistant (CR) and in CQ-sensitive (CS) P. berghei is involved in the infected erythrocytes (RBC) or in the parasites.
METHODS: The concentration of CQ in infected RBC and parasites following ig administration of CQ to CS and CR infected mice was determined by HPLC method (extra standard).
RESULTS: 3 h after 4.06 mg/kg and 400 mg/kg administration, the accumulation of CQ in both infected RBC was similar, but in CR was 54.0% and 42.1% less than in CS (P < 0.001) respectively. The CQ accumulation in CS 3 h and 7 h after ig administration of CQ 400 mg/kg was similar (0.780 +/- 0.128 nmol/protein and 0.760 +/- 0.180 nmol/mg protein), while in CR the CQ-accumulation was higher at 7 h than that at 3 h after CQ administration (0.452 +/- 0.079 nmol/mg protein and 0.559 +/- 0.124 nmol/mg protein P < 0.02).
CONCLUSION: The low CQ accumulation in CR is attributable to the parasite rather than to the infected RBC, and CR was not found to excrete CQ more rapidly than CS.