Mechanically, GDNF can enhance the differentiation and survival of DA neurons and regulate the generation and release of neurotransmitters by DA neurons and 5-hydroxytryptamine (5HT) neurons.[34] In certain cases, 5HT may pursue awakening and inhibit rapid-eye-movement (REM) sleep, while in others, it may enhance sleeping.[35] A study showed that the activation of DRN5HT neurons may relieve anxiety, thereby leading to non-REM (NREM) sleep under mild stress.[36]. This evidence concerns the gene GDNF and Anxiety.