Activating serotonin 2C receptors in the brain's reward control area increases depression-like behaviors in rats with one-sided Parkinson's

Intra-LHb injection of the 5-HT2C receptor agonist Ro60-0175 decreased sucrose consumption and increased immobility time in rats with unilateral 6-hydroxydopamine lesions.

• Unilateral lesions of the substantia nigra induced depressive-like responses in rats compared to sham-operated controls.
• Activation of 5-HT2C receptors in the lateral habenula increased the firing rate of glutamate neurons in both sham-operated and lesioned rats.
• In lesioned rats, the duration of Ro60-0175's effect on the firing rate of glutamate neurons was markedly prolonged.
• Ro60-0175 administration decreased levels of dopamine, serotonin, and noradrenaline in the medial prefrontal cortex, habenula, hippocampus, and amygdala in both groups.
• The lesion did not alter the percentage of neurons co-expressing EAAC1 and 5-HT2C receptors in the lateral habenula.

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