Trpc2 gene impacts on maternal aggression, accessory olfactory bulb anatomy and brain activity

Area of Science:

• Neuroscience
• Genetics
• Behavioral Biology

Background:

• The Trpc2 gene encodes an ion channel in the vomeronasal organ (VNO), essential for pheromone detection.
• Trpc2 knockout (KO) mice are used to study VNO function in pheromonally mediated behaviors.
• Previous research has not examined the impact of Trpc2 on brain activity.

Purpose of the Study:

• To investigate the effect of Trpc2 gene deletion on brain activity in maternal aggression.
• To analyze Fos immunoreactivity (Fos-IR) in specific brain regions of lactating dams.
• To correlate anatomical changes in the accessory olfactory bulb (AOB) with behavioral deficits.

Main Methods:

• Intruder tests were performed on lactating Trpc2 KO and wild-type dams.
• Fos-IR was quantified in the vomeronasal amygdala, hypothalamus, olfactory regions, and AOB.
• Home-cage observations were conducted to assess maternal behaviors like nest-building.

Main Results:

• Trpc2 deletion significantly reduced maternal aggression, confirming previous findings.
• Differential hypotrophy of the AOB's glomerular layer was observed in KO mice, with anterior and posterior regions showing distinct alterations.
• Fos-IR analysis revealed Trpc2 deletion impacts 21 brain regions involved in emotion, aggression, and olfaction.
• KO dams exhibited deficits in nest-building behavior, suggesting a role for pup pheromones.

Conclusions:

• The Trpc2 gene plays a significant role in modulating maternal aggression and associated brain activity.
• Altered AOB anatomy in Trpc2 KO mice suggests residual VNO function.
• VNO signals mediated by Trpc2 influence a widespread neural network involved in sensory processing and maternal behaviors.