Furthermore, the preservation of transient 5-HTT expression was found in these long-term aDRG NSCs. The expression of serotonin is known to be important in embryonic and sensory system development. Transient expression of 5-HTT, responsible for uptake of serotonin, has been reported in developing neural crest tissues including DRG (5,16,19) and somatosensory cortex (41). We were expecting that eDRG NSCs, but not aDRG NSCs, would possess 5-HTT immunostaining. On the contrary, we found 5-HTT-im on both aDRG and eDRG NSCs.
