The cellular trafficking of arachidonoyl ethanolamide (anandamide; AEA) by neurons is dominated by hydrolysis and/or transport by fatty acyl amide hydrolase (FAAH) within the neurons.1 SKM 4-45-1 is a labeled analog of AEA that is non-fluorescent when outside the cell. Upon transport into the cell interior, it is cleaved by esterases to give a bright fluorescence at 530 nm. SKM 4-45-1 uptake into C6 glioma cells is inhibited by AEA and its analogs, and conversely SKM 4-45-1 inhibits the uptake of tritiated AEA, indicating that they compete for the AEA transporter.
