783.15 - The Effect of Atrazine on Fear Behaviors in Rats  lt;/p"gt;

Melissa Rivera-Lopez (University of Puerto Rico, Medical Sciences Campus), Osmarie Martines-Guzman (University of Puerto Rico, Medical Sciences Campus), Mauricio Caceres-Chacon (University of Puerto Rico, Medical Sciences Campus), Gabriela Hernandez-Busot (University of Puerto Rico, Rio piedras Campus), Sian Rodriguez-Rosado (University of Puerto Rico, Rio piedras Campus), Alexdiel Figueroa-Perez (University of Puerto Rico, Rio piedras Campus), Demetrio Sierra-Mercado (University of Puerto Rico, Medical Sciences Campus)

Atrazine (ATR) is a widely used herbicide in agriculture. Unfortunately, excessive use of ATR has led to the contamination of food and drinking sources (Mosquin et al., 2012; Whitmore and Chen, 2013). Subsequently, this has led to humans becoming exposed to ATR in their daily life. Animal studies have shown that ATR can influence emotionally relevant behaviors such as anxiety in rodents (Ma et al., 2018; Chavez-Pichardo et al., 2020). However, other emotional behaviors such as fear remain unexplored. To address this gap, rats were exposed to ATR in their drinking water at a dose considered safe for ingestion (0.035mg/kg; Environmental Protection Agency), whereas control animals received filtered water. Both groups had ad libitum access to water for four months. Following exposure, fear was assessed using Pavlovian fear conditioning where rats learn that a tone predicts a shock by exhibiting freezing behavior to the tone. We hypothesized that rats exposed to ATR would show increased fear expression compared to control rats. Anxiety-like behavior was also examined using the open field test. During fear conditioning no differences were observed in freezing behavior between groups (ATR: 58%, Controls: 59%; n=10; p=0.3714). In the open field test, ATR rats trended towards having more center entries (ATR: 23.8, Controls: 14.8; n=10, p=0.0570) and decreased time spent in corners (ATR: 70.5 s, Controls: 114.2 s; n=10, p=0.0248) compared to controls. These results suggest that ATR does not affect fear behaviors, but it can decrease anxiety-like behaviors. Future directions aim at examining brain regions key to emotional behaviors, such as the amygdala, using immunohistochemistry. Our findings may help elucidate how prolonged ingestion of atrazine at a dose considered safe for humans may influence emotionally relevant behaviors.

NIGMS/NIH Center of Biomedical Research Excellence (COBRE II)
RCMI Seed monies and Pilot Project Program 8G12MD007600
Brain and Behavior Research Foundation (NARSAD)
Puerto Rico Center Clinical Translational Research Consortium (PRCTRC)
National Science Foundation CREST (undergraduate amp;amp; graduate fellowships)
Neuro-ID undergraduate research fellowship
NIH National Institute of Neurological Disorders and Stroke R21NS119991.