Abstract: The properties of Na-K-ATPase in the nerve system of house flies were described For-Na-K ATPase the optimum pH and temperature were 7.0～8.0and 35～40℃ respectively, the K_m value was 0.22 mmol/L ATP and Vmax was approximately 555.56 nmol P_i/(mg·protein·min). The Na-K-ATPase activities in susceptible (SP) and Del-R、2Cl-R house fly strains were determined. The results indicated that there was no significant difference in Na-K-ATPase activities among the three strains. Inhibition of deltamethrin and permethrin on Na-K-ATPase activity was also studied. The results showed that the two pyrethroids inhibited obviously the Na-K-ATPase activity in the susceptible strain, but no effect in the resistant strain

Key words: Na-K-ATPase, house fly, pyrethroid