Enhancement of drug susceptibility in Plasmodium falciparum in vitro and Plasmodium berghei in vivo by mixed-function oxidase inhibitors
Enhancement of drug susceptibility in Plasmodium falciparum in vitro and Plasmodium berghei in vivo by mixed-function oxidase inhibitors
复制标题
混合功能氧化酶抑制剂增强体外恶性疟原虫和体内伯氏疟原虫的药物敏感性
DOI：
10.1128/aac.37.6.1318
复制
发表时间：
1993
影响因子：
4.9
通讯作者：
S. A. Ward
中科院分区：
文献类型：
--
作者：
A. Ndifor;R. E. Howells;P. Bray;J L Ngu;S. A. Ward
A number of compounds, as exemplified by verapamil and desipramine, have been shown to enhance the susceptibility of resistant malaria parasites to chloroquine. The mechanism by which these agents reverse resistance is still controversial but is though to involve alterations in drug transport causing an increase in steady-state drug concentrations. We have proposed that an alternative resistance mechanism may involve the metabolic deactivation of the drug in some resistant parasites via cytochrome P-450 mixed-function oxidases. If the hypothesis is true, it should be possible to alter drug susceptibility in malaria parasites by the use of agents known to inhibit or induce cytochrome P-450 activities. We have assessed the ability of known inhibitors of cytochrome P-450 enzymes (cimetidine, metyrapone, and alpha-naphthoflavone) to enhance chloroquine susceptibility in Plasmodium falciparum culture-adapted and wild-type isolates in vitro and P. berghei in vivo. In all three systems, the inhibitor cimetidine enhanced parasite susceptibility to chloroquine, and this increase in susceptibility was unrelated to changes in chloroquine steady-state concentrations in vitro or to alterations in host pharmacokinetics in vivo. Additionally, the cytochrome P-450 inducer phenobarbital produced slight decreases in P. falciparum drug susceptibility in vitro. We have compared the ability of the cytochrome P-450 inhibitors cimetidine and metyrapone to enhance drug susceptibility with that of verapamil by using wild-type malaria isolates obtained from Cameroon. Verapamil completely reversed resistance, i.e., to below the cutoff point of 70 nM, in all the resistant isolates. Cimetidine enhanced chloroquine susceptibility in 60% of the isolates and reduced 50% inhibitory concentrations by at least 43% in all the resistant isolates. The compounds tested had little or no effect on the 50% inhibitory concentrations for the susceptible isolates. The data support a possible role for detoxification in chloroquine resistance, and even in the absence of such a process we have observed apparent chemosensitization by agents whose common biological feature is the inhibition of cytochrome P-450 enzymes. Additionally, sensitization has been observed in wild-type isolates of P. falciparum obtained form immune residents of an area of endemicity as well as culture-adapted parasites.
用微粒体单加氧酶抑制剂治疗受感染的小鼠，抑制伯氏疟原虫的氯喹耐药性。
影响因子：
11.1
作者：
Rabinovich,SA;Kulikovskaya,IM;Maksakovskaya,EV;Chekhonadskikh,TV;Pankova,TG;Salganik,RI
通讯作者：
Salganik,RI