Inhibition of acetylcholinesterase in the australian freshwater shrimp (<i>Paratya australiensis</i>) by profenofos

Abstract

Abstract Profenofos induced significant inhibitory effects on the AChE activity of Paratya australiensis ranging from &amp;gt;40% inhibition at sublethal concentrations of 0.1 to 1.0 μg/L to &amp;gt;80% inhibition at lethal concentrations of ≥10 μg/L. Sublethal chronic exposure (21 d) at a concentration of 0.15 μg/L caused persistent reduction in AChE activity of up to 60%, whereas recovery of AChE activity to normal levels from a 24-h exposure to 0.1 μg/L profenofos required less than 9 d. Shrimp were exposed to 0.1 μg/L profenofos for 24 h and then allowed a period of recovery in pesticide-free water; at the end of this treatment the AChE activity of affected shrimp approached control level. Subsequent 24-h exposures with intermittent stay in pesticide-free water for the same duration as the initial recovery phase resulted in greater inhibition in AChE activity as compared to the initial 24-h exposure. Furthermore, the AChE activity of shrimp at the end of the recovery phases remained significantly depressed.