Abstract: 【Aim】 To investigate the effect of deoxypodophyllotoxin on the signal pathway of nicotinic acetylcholine receptor of Periplaneta americana. 【Methods】 Three critical signal molecule genes (mRNA of nAChR, CaM and CaMKⅡ) extracted from the head of P. americana adults were cloned and sequenced. After P. americana were injected with different concentrations (10, 45, 80, 115 and 150 μg/μL) of DOP, the mRNA expression levels of three genes at 24 and 48 h after treatment were assayed, respectively, by real-time PCR. 【Results】 Sequence alignment of mRNA revealed that P. americana nAChR gene (539 bp) shares 84% nucleotide sequence identity to nAChR α6 gene from Tribolium castaneum; P. americana CaM gene (435 bp) has 85% nucleotide sequence identity to Graphocephala atropunctata CaM gene; P. americana CaMKⅡgene (513 bp), however, shows 77% nucleotide sequence identity to Drosophila melanogaster CaMKⅡ gene. In P. americana treated with DOP for 48 h, the mRNA expression of nAChR α6, CaM and CaMKII all increased in treatments with low concentration of DOP, reached the peak at 45-80 μg/μL, and then decreased when the DOP concentration was 80-150 μg/μL. 【Conclusion】 After long-term accumulation in P. americana, DOP binding with nAChR leads to the triggering of CaM-CaMKII cascade, resulting in the changes in mRNA expression of three genes (nAChR, CaM and CaMKⅡ genes), which are up-regulated by low concentration of DOP and inhibited by high concentration of DOP. Therefore, DOP could exert the potential toxic effects on of the nervous system of P. americana.

Key words: Periplaneta americana, deoxypodophyllotoxin, real-time PCR, gene cloning, nicotinic acetylcholine receptor, signal molecule