Response and Recovery of Brain Acetylcholinesterase Activity in Atlantic Salmon (Salmo salar) Exposed to Fenitrothion

Abstract

Atlantic salmon (Salmo salar) parr were exposed to a number of concentrations of either technical grade fenitrothion or an operational formulation of the pesticide for 7 d or to the operational formulation for two, 24 h periods separated by 7 d. Brain acetylcholinesterase (AChE) activity decreased as concentration, of fenitrothion increased. Recovery period was directly related to amount of depression, with recovery of AChE from exposure to 0.004 μL/L fenitrothion taking less than 1 wk. Samples must be taken soon after spray operations to detect exposure to such low levels of fenitrothion through AChE monitoring.

Increased recovery of brain acetylcholinesterase activity in dichlorvos-intoxicated European eels Anguilla anguilla by bath treatment with N-acetylcysteine

“…The recovery of brain AChE activity is a function of the degree of the initial inhibition (Morgan et al 1990). As the recovery of enzyme activity is basically a result of the de novo synthesis of enzyme protein, the greater the degree of inhibition, the more protein synthesis is required (Fulton & Key 2001).…”

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“…Similarly, after exposing Gambussia affinis to monochrotofos, AChE activity was recovered in 20 d (Kavitha and Venkateswara, 2007). AChE activity in Salmo salar exposed to fenitrothion was reversible after 6 weeks of recovery (Morgan et al, 1990).…”

Ecological Risk Assessment for Chlorpyrifos in Terrestrial and Aquatic Systems in the United States

“…If, as is generally suggested (Morgan et al 1990 ), recovery of phosphorylated AChE in fi sh requires synthesis of new enzyme, rates of recovery would be slow and dependent on rates of metabolism and the physiological and biochemical characteristics of fi shes, which appear to be unknown. In the absence of having a model for predicting recovery periods, empirical observations suggest that inter-exposure intervals of the order of 4-8 wk might be required for complete recovery of AChE in fi sh.…”

“…Similar observations have been reported for other organophosphorus insecticides. For example, activity of brain-AChE in Atlantic salmon parr ( Salmo salar ) exposed to formulated fenitrothion (50% inhibition at initiation of recovery) and transferred to fresh water, recovered to 66% of control values in 7 d and 93% in 42 d (Morgan et al 1990 ). It is not known if AChE recovery rates in fi sh differ among organophosphorus insecticides having O -methyl (fenitrothion) or O -ethyl (CPY) substituents, and whether there are models, with which recovery rates can be extrapolated.…”