Central Expression of Peripheral Cannabinoid Receptors

Science's STKE  18 Oct 2005:
Vol. 2005, Issue 306, pp. tw373
DOI: 10.1126/stke.3062005tw373

The discovery of endocannabinoids, which act as retrograde messengers in the brain, changed the way we think about the flow of information across the synapse. Are the endogenous actions of endocannabinoids in the brain solely accounted for by activation of CB1 receptors? Although there are hints for the presence of another receptor type, there have been no reports of an alternative CB receptor in the brain. Using reverse transcription polymerase chain reaction (RT-PCR), pharmacological, and behavioral evidence, Van Sickle et al. show that functional cannabinoid CB2 receptors, a receptor subtype traditionally considered to be expressed in immune tissues and circulating immune cells, are also present in brainstem neurons. This finding could lead to new therapies without the usual drawbacks of addiction and mind alteration traditionally associated with the consumption of cannabis derivatives.

M. D. Van Sickle, M. Duncan, P. J. Kingsley, A. Mouihate, P. Urbani, K. Mackie, N. Stella, A. Makriyannis, D. Piomelli, J. S. Davison, L. J. Marnett, V. D. Marzo, Q. J. Pittman, K. D. Patel, K. A. Sharkey, Identification and functional characterization of brainstem cannabinoid CB2 receptors. Science 310, 329-332 (2005). [Abstract] [Full Text]