Brain research
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Stress-induced anhedonia correlates with lower hippocampal serotonin transporter protein expression.
The serotonin transporter (5-HTT) regulates the extracellular concentration of serotonin, influencing neurotransmission. Evidence suggests that 5-HTT is altered during depression, but the precise changes in 5-HTT expression in the pathogenesis and treatment of depression are not clear. We investigated the protein expression of hippocampal 5-HTT in CD-1 mice exposed to unpredictable chronic mild stress for 10 continuous weeks. ⋯ The treatment did not alter the changes in the treatment-resistant anhedonic mice or in the non-anhedonic mice. The data indicate that down-regulation of hippocampal 5-HTT protein expression is a signature change associated with anhedonia, a key endophenotype of clinical depression. Differential changes in 5-HTT expression may contribute to variations in the susceptibility to anhedonia.