Effects of systemically-administered thiamethoxam on behaviour in The rat

Wood, Alexis
Soriani, Maria
Cormier, Jerrica
Tasker, R. Andrew

2021 UPEI Undergraduate Research Days

Abstract

2021

Biomedical Sciences

Neonicotinoid insecticides such as thiamethoxam are widely used in agricultural, commercial, residential, and veterinary settings. These drugs cause motor paralysis and death in insects through activation of nicotinic acetylcholine receptors (nAChR) located at the neuromuscular junction (NMJ) but have minimal activity at the mammalian NMJ. The effects of these drugs on the different subtypes of nAChRs found in the mammalian brain, however, is unknown. Effects on central nervous system function Show moreNeonicotinoid insecticides such as thiamethoxam are widely used in agricultural, commercial, residential, and veterinary settings. These drugs cause motor paralysis and death in insects through activation of nicotinic acetylcholine receptors (nAChR) located at the neuromuscular junction (NMJ) but have minimal activity at the mammalian NMJ. The effects of these drugs on the different subtypes of nAChRs found in the mammalian brain, however, is unknown. Effects on central nervous system function were measured in male Sprague-Dawley (CD) rats (N=32; 299-340g) following subcutaneous injection of 3 mg/kg thiamethoxam, 0.5 mg/kg nicotine (positive control) or saline vehicle. Tests used were Spontaneous Alternation (short-term memory), Horizontal Ladder (locomotor coordination) and Novel Object Recognition (NOR) (longer term memory). No significant differences were found between groups although some interesting trends were noted. In the horizontal ladder both thiamethoxam and nicotine treated rats appeared to take longer to cross the ladder and to spend more time with the novel object than the familiar object in the NOR task than did their saline counterparts. We conclude that systemic thiamethoxam has no significant effects on behaviour at the dose tested but that further investigations with higher doses and/or larger group sizes are probably warranted. AW is supported by an NSERC USRA award and research funding was provided by an NSERC Discovery grant to RAT. Show less