Endocannabinoids (endogenous ligands at CB receptors) such as anandamide serve as retrograde neuromodulators of synaptic activity. They are released postsynaptically by a variety of stimuli upon demand, travel across the synaptic cleft, and then activate presynaptic CB receptors. A membrane transporter actively takes anandamide into the cell. Anandamide is then broken down by fatty acid amide hydrolase (FAAH) [13–15].
