HCRTR1 and depressive disorder: After injection of one of 3 TM peptides (5-HT1AR-TM4, 5-HT1AR-TM5, and OX1RTM5) into the lateral ventricle of CUMS rats, specific depression-related functions were reverted via inhibiting the interface of the 5-HT1AR/OX1R heterodimer (Zhang R. et al., 2022).