No exact and digital diagnostic methods for depression have been found. In this study, we prepared a 5-HT biosensor based on screen-printed electrode and applied it to a rat depression model caused by chronic unpredictable mild stress (CUMS). During CUMS, the blood 5-HT and the depression behavior of the depressed rats and the rats treated by antidepressants were recorded. The correlation coefficient of 5-HT was 0.9966 (0 – 4 × 10−6 M) on the sensor. Results demonstrated that 5-HT level of the depressed rats declined while the depression behavior was aggravated. Fluoxetine (20 mg/kg) and lentinan (10, 20 mg/kg) mildly elevated 5-HT level and slowly regulated the behavior. Mifepristone (20 mg/kg) and Rhizoma Coptidis water extract (10, 20, 100 mg/kg) quickly reversed 5-HT level and the depression behavior. This sensor can accurately test blood 5-HT and might be applied to rapid diagnosis for depression and evaluation of antidepressants effect.
