168 + CO-5-Microcine | Postnatal GABA shift in the piriform cortex may support the ability of home-nest odor discrimination in infant rats


Author: Christell Tatiana Becerra Flores | Email: 174203@unsaac.edu.pe

Christell Becerra , Carlos Medina-Saldívar , Enver M. Oruro , Grace E. Pardo , Luis F. Pacheco-Otálora 1

1° Laboratorio de Investigación en Neurociencias Universidad Andina del Cusco
2° Laboratorio de Neurocomputación, Simulación Social y Sistemas Complejos Universidad Andina del Cusco

Background: In rat pups, home odor preference is present at postnatal day (P) 5; however, the ability to discriminate home nest odors from other nests appears on P10. The developmental shift in GABA signaling in the piriform cortex (PCX) could be a possible explanation at the neuronal level for why P10 pups discriminate their nest odor from other similar nests but not younger pups.
Methods: To test this hypothesis, we used a computational model of the PCx for rat pups constructed with our experimental data, including data from P5 and P10 PCx GABA synaptic input profile, then simulated the home-odor processing discrimination. During both periods, we also studied the expression of the KCC2 chloride extruder in the PCX using RT-qPCR and Western blotting.
Results: The results show that the number of active neurons and evoked spikes in response to two highly similar odors were higher than for the other nest in the P10 circuit, but this comparison was identical in the P5 circuit, suggesting discrimination odor ability in the P10 circuit but not in P5. Moreover, gene and protein expression of KCC2 was significantly upregulated in P10 compared to P5, suggesting a shift of GABAergic transmission from depolarizing to hyperpolarizing.
Conclusions: Our results support the idea that the ability to discriminate between closely associated nest odors in P10 rat pups may be attributed to the developmental shift in GABAergic signaling in the PCx between P5 and P10.