Related Experiment Video
Updated: Mar 1, 2026
Induction of Maternal Immune Activation in Mice at Mid-gestation Stage with Viral Mimic PolyI:C
Published on: March 25, 2016
Methamidophos, an Organophosphorus Insecticide, Induces Pro-aggressive Behaviour in Mice
Cristina Paula do Nascimento1, Gabriella Xavier Maretto2, Graziany Leite Moreira Marques1
1Department of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Av. Marechal Campos, 1468, Maruípe, Vitória, ES, 29043-900, Brazil.
Abstract:
Although evidence indicates that exposure to organophosphorus (OP) pesticides induces neurobehavioral disorders, little is known about the effects of OP on aggressive behaviour. Our study investigated the effects of repeated exposure to an OP pesticide, methamidophos, on the isolation-induced aggressive behaviour in mice. Forty seven male mice were individually housed for a month. Socially isolated animals were then confronted with a standard non-isolated opponent for 15 min (pre-treatment trial), and the latency and frequency of aggressive and general exploratory behaviours were recorded. Based on the presence of attack behaviour in the pre-treatment trial, mice were classified as isolation-induced aggressive and non-aggressive. All mice were then treated for 7 days with methamidophos (3.5 mg/kg/day, n = 22, intraperitoneal (i.p.)) or saline (1 mL/kg/day, control group, n = 25, i.p.), and a second trial was performed. Repeated exposure to methamidophos induced attack behaviour in non-aggressive mice. The treatment with methamidophos also decreased plasma butyrylcholinesterase and brain acetylcholinesterase activity. These results suggest that methamidophos has a pro-aggressive effect on socially isolated mice.
Insights
Organophosphorus pesticide exposure can alter behavior. Methamidophos, an organophosphorus pesticide, induced aggressive behavior in previously non-aggressive mice and decreased key enzyme activity.
Area of Science:
- Neuroscience
- Toxicology
- Behavioral Science
Background:
- Organophosphorus (OP) pesticides are known to cause neurobehavioral disorders.
- However, the specific impact of OP pesticides on aggressive behavior remains largely unexplored.
Purpose of the Study:
- This study investigated the pro-aggressive effects of methamidophos, an OP pesticide, in socially isolated mice.
- The research aimed to understand how methamidophos influences aggressive and exploratory behaviors.
Main Methods:
- Forty-seven male mice were socially isolated and assessed for aggression.
- Mice received daily intraperitoneal injections of methamidophos (3.5 mg/kg) or saline for seven days.
- Aggressive and exploratory behaviors were recorded before and after treatment.
Main Results:
- Repeated methamidophos exposure induced attack behavior in mice that were not previously aggressive.
- Methamidophos treatment significantly reduced plasma butyrylcholinesterase and brain acetylcholinesterase activity.
- A correlation was observed between pesticide exposure and increased aggressive tendencies.
Conclusions:
- Methamidophos exhibits pro-aggressive effects in socially isolated mice.
- The findings suggest a link between OP pesticide exposure and altered aggressive behavior.
- Enzyme inhibition by methamidophos may contribute to its behavioral effects.
