Alterations of Glutamatergic Markers in the Prefrontal Cortex of Serotonin Transporter Knockout Rats: A Developmental Timeline.

The serotoninergic system plays a key role in environmental sensitivity, potentially through down-stream effects on the GABAergic and glutamatergic systems. We previously demonstrated that juvenile serotonin transporter knockout (SERT-/-) rats, showing increased environmental sensitivity, exhibit a decreased GABA-mediated inhibitory tone in the cortex. Since the GABAergic and glutamatergic systems are tightly interconnected, we here analyzed glutamatergic markers in the prefrontal cortex of SERT-/- rats, from the early stages of life until adulthood. We found that SERT inactivation in pre-weaning, juvenile, and adult rats was associated with reduced expression of proteins essential for the glutamatergic synapses such as GluN1, PSD95, CDC42, and SEPT7. These lifelong molecular changes may destabilize glutamatergic signaling and possibly contribute to stress sensitivity and vulnerability to stress-related disorders associated with SERT alteration.