Measuring endocannabinoid hydrolysis: refining our tools and understanding.

Endocannabinoids (eCBs) are lipid transmitters that are released from membrane precursors in response to specific stimuli, activate cannabinoid receptors--the molecular targets of compounds produced by Cannabis sativa--and are then rapidly inactivated by uptake and enzymatic hydrolysis. This signaling system is implicated in a wide range of biological processes, including pain sensation, immunomodulation, appetite regulation, development, and cognitive and emotional states. The balance between eCB release and inactivation determines the extent of eCB accumulation, with enzymatic hydrolysis functioning as an important limiting step. Pharmacological inhibition of eCB-hydrolyzing enzymes offers great therapeutic and experimental promise for enhancing this ubiquitous signaling system only where and when these transmitters are naturally produced. The following mini-review summarizes the latest developments concerning eCB-hydrolyzing enzymes, with an emphasis on the techniques used to measure their activities and how these have helped increase our understanding of the role that eCBs play in regulating fundamental biological functions.