Fig. (1).

The endocannabinoid system in aging. The CB₁ cannabinoid receptor, anandamide, 2-AG, monoacylglycerol lipase (MAGL), anandamide membrane transporter (AMT), and fatty acid amide hydrolase (FAAH) belong to the endocannabinoid system. Briefly, anandamide is synthesized by the activity of FAAH in the postsynaptic terminal. Next, the AMT displaces anandamide into the extracellular space to binding to the CB₁ cannabinoid receptor. In addition, the 2-AG also binds to the CB₁ cannabinoid receptor at the presynaptic terminal. As mentioned in the text, anandamide, 2-AG, the CB₁ cannabinoid receptor, FAAH, and AMT participate in sleep modulation. As shown in the drawing, the CB₁ cannabinoid receptor, anandamide, and 2-AG levels have been found decreased in aging. However, the activity of FAAH, AMT, and MAGL across aging remains to be described.