Modulation of the serotonin system by endocannabinoid signaling

► Endocannabinoids modulate the strength of glutamate synapses in the dorsal raphe via CB1 receptors. ► Dorsal raphe serotonin neurons release endocannabinoids “on demand”. ► The release of endocannabinoids from serotonin fine tune synaptic transmission in the dorsal raphe. ► The cross talk between endocannabinoids and the serotonin system regulates stress responses.