Carbaryl is a carbamate insecticide that inhibits acetylcholinesterase (AChE; IC₅₀= 13.6 nM forA. gambiaeAChE2 expressed in Sf9 cells; K_i= 5.7 &#181M for rat brain AChE).^1,2Carbaryl administered at a dose of 30 mg/kg for 28 days in rats decreases the weight of spleen and thymus, proliferation of lymphocytes, and serum levels of IL-2, IFN-γ, IL-1β, and TNF-α, and increases the serum levels of IL-4 and IL-10.³It increases CaMKII, GAP-43, and tau protein levels in the hippocampus and tau levels in the cortex of mice 24 hours after administration of doses ranging from 0.5 to 20 mg/kg on postnatal day ten, whereas tau protein levels are decreased four months after administration with no change in CaMKII or GAP-43 compared with control mice. These effects occur at non-toxic doses where acetylcholinesterase is inhibited only during the first six hours following treatment. Formulations containing carbaryl have been used to control insects in agriculture.

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