Long-term sarcosine treatment exerts antidepressant-like effects in the forced swim test in chronic unpredictable stress (CUS)-exposed rats but not in naive rats.

Long-term sarcosine treatment increases the expression of the mTOR signaling-related proteins and increases AMPAR membrane insertion in the hippocampus in both naive rats and CUS-exposed rats.

The distinct sensitivity to long-term sarcosine treatment in rats with or without CUS is found after long-term sarcosine treatment, which is not associated with the activated mTOR signaling pathway or increased AMPAR membrane insertion.