AN ELECTROPHYIOLOGICAL INVESTINGATION OF TARGET SITE INSESITIVITY IN PERMETHRN-RESISTANT AND SUSCEPTIBLE STRAIN OF ANOPHELES STEPHENSI

AN ELECTROPHYIOLOGICAL INVESTINGATION OF TARGET SITE INSESITIVITY IN PERMETHRN-RESISTANT AND SUSCEPTIBLE STRAIN OF ANOPHELES STEPHENSI

Blog Article

It was shown that permethrin resistance in adult Anopheles stephensi is due to at least three separate mechanisms.Cytochrome P-450s and esterases are responsible for two-thirds of the 8-fold enhanced tolerance of the DUB-APR resistant strain as compared with a sensitive strain, IND-S.It was postulated that target site insensitivity is also involved.To test this hypothesis, we conducted a neurophysiological study with the thoracic nerves of adult female An.stephensi under perfusion with saline.

Spontaneous neural activity was recorded with saline A alone and in the presence of permethrin.There was no change in the frequency of spontaneous firing dose of 10-3Molar perethrin rapidly produced a 3-fold increase in firing rate in the susceptible strain.In contrast, the resistant strain did not respond to this concentration.In a cumulative dose assay, the susceptible strain responded to the lowest concentration of permethrin (10-3 Molar), but the resistant strain required SWEATERS a much higher dose (10-8- 10+-7 molar) to produce the same rise in frequency of actin potentials.This strongly suggests that nerve insensitivity contributes to permethrin resistance in this mosquito.