.”We have studied the status of some of the components of the endocannabinoid system, fatty acid amide hydrolase and cannabinoid CB1 and CB2 receptors, in postmortem brains from patients with Alzheimer’s disease. Our results show that both fatty acid amide hydrolase and cannabinoid CB2 receptors are abundantly and selectively expressed in neuritic plaque-associated astrocytes and microglia, respectively, whereas the expression of CB1 receptors remains unchanged. In addition, the hydrolase activity seems to be elevated in the plaques and surrounding areas.

Thus, some elements of the endocannabinoid system may be postulated as possible modulators of the inflammatory response associated with this neurodegenerative process and as possible targets for new therapeutic approaches.

To our knowledge, this report is the first evidence for the presence of CB₂ receptors in the human CNS. Furthermore, these receptors have recently been reported to play an important role in microglial migration. It is important to note that we detected CB₂ receptors only in microglial cells, which is in agreement with the well known immunomodulatory effects of CB₂ activation. Thus, many studies have shown that CB₂ receptor activation leads to a myriad of changes in the production of inflammation-related substances, although with results that vary depending on the experimental model used and the concentration of cannabinoids used.

 In any case, the selective presence of CB₂ receptors in microglial cells opens new perspectives on the role of CB₂ receptors in the human CNS and suggests that the modulation of their activity may have therapeutic implications.”

http://www.jneurosci.org/content/23/35/11136.long