The paper:
E. Ryberg et al., “The orphan receptor GPR55 is a novel cannabinoid receptor,” British Journal of Pharmacology, 152:1092–101. (Cited in 99 papers)
The finding:
Expressing the orphan receptor GPR55 on the membranes of human embryonic kidney cells, biochemist Peter Greasley and his colleagues at AstraZeneca discovered that it bound many of the same ligands as CB1 and CB2, the two known cannabinoid receptors. “It raised the question of whether [GPR55] might be [another] cannabinoid receptor,” says pharmacologist Roger Pertwee of the University of Aberdeen in Scotland, potentially serving as a novel drug target to suppress inflammation, for example.
The difference:
While GPR55 was bound by a number of the same ligands known to bind CB1 and CB2—including the principle psychoactive component of cannabis (Δ9-THC)—it was also activated by other ligands, including one that made CB1 and CB2 less likely to be activated (antagonists).
The follow-up:
More recent studies ...
