Table 11.

Table showing the main findings regarding the effects of melatonin on neurogenesis impairment caused by environmental factors and the respective molecular mechanisms in the in vitro studies.

Cells	Lowest Dosage Causing an Observable Effect	Main Findings	Molecular Mechanisms	References
Adult hippocampal NSCs (from 8-week-old rats) exposed to dexamethasone (DEX)	1 μM melatonin, treated 30 min before 1 μM DEX treatment, for 5 days	Prevented DEX-induced reduction in Ki67 and Nestin expression in the neurosphere	Melatonin receptors and glucocorticoid receptor; reversed the DEX-induced changes in ERK1/2, cyclin E, and CDK2	Ekthuwapranee et al., 2015 [107]
Mouse NSCs (E12.5) exposed to tri-ortho-cresyl phosphate (TOCP)	40 μM melatonin, treated before TOCP exposure for 24 h	Prevented the decrease in cell viability after TOCP exposure Prevented TOCP-induced autophagy	Reduced production of ROS; restored ERK1/2 signaling pathway	Liu et al., 2020 [108]