ISOLATION AND MEASUREMENT OF THE ENDOGENOUS CANNABINOID RECEPTOR AGONIST, ANANDAMIDE, IN BRAIN AND PERIPHERAL-TISSUES OF HUMAN AND RAT

Anandamide (arachidonylethanolamide) is a novel lipid neurotransmitter first isolated from porcine brain which has been shown to be a functi onal agonist for the cannabinoid CB1 and CB2 receptors, Anandamide has never been isolated from human brain or peripheral tissues and its ro le in human physiology has not been examined, Anandamide was measured by LC/MS/MS and was found in human and rat hippocampus (and human para hippocampal cortex), striatum, and cerebellum, brain areas known to ex press high levels of CB1 cannabinoid receptors, Significant levels of anandamide were also found in the thalamus which expresses low levels of CB1 receptors, Anandamide was also found in human and rat spleen wh ich expresses high levels of the CB2 cannabinoid receptor, Small amoun ts of anandamide were also detected in human heart and rat skin, Only trace quantities were detected in pooled human serum, plasma, and CSF, The distribution of anandamide in human brain and spleen supports its potential role as an endogenous agonist in central and peripheral tis sues, The low levels found in serum, plasma, and CSF suggest that it i s metabolized in tissues where it is synthesized, and that its action is probably not hormonal in nature.