The orphan receptor GPR55 is a novel cannabinoid receptor

[Shampoo]

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Description:
We demonstrate that GPR55 binds to and is activated by the cannabinoid ligand CP55940. In addition endocannabinoids including anandamide and virodhamine activate GTPgammaS binding via GPR55 with nM potencies. Ligands such as cannabidiol and abnormal cannabidiol which exhibit no CB1 or CB2 activity and are believed to function at a novel cannabinoid receptor, also showed activity at GPR55. GPR55 couples to Galpha13 and can mediate activation of rhoA, cdc42 and rac1.

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Reputation Comments on this post:

	Good find intresting read
	I read this and found it fascinating. Thanks for sharing.

[Alfa]

Comment:

Woah! Very interesting. So this may mean that products like spice do not mainly affect the CB1 cannabinoid receptor, but this newly discovered one.

I wonder how different the pharmacological profile of CP55.940 and CP47.497 are compared to cannabis.

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[Shampoo]

Originally Posted by Alfa

So this may mean that products like spice do not mainly affect the CB1 cannabinoid receptor, but this newly discovered one.

I wonder how different the pharmacological profile of CP55.940 and CP47.497 are compared to cannabis.

Well, the assay done in the study shows that CP55.940, ∆-9-THC, anandamide and 2-AG all act as agonists at the GPR55 protein, and in very low (i.e. nM) concentrations, suggesting that these compounds likely have a high affinity for this receptor.

Figure 5a displays G-protein binding activity over varying concentrations of CP55.940 and ∆-9-THC, where we can clearly see that CP55.940 elicits greater activation in the receptor than ∆-9-THC. Additionally, the similar shape of their curves suggests a similar if not identical mechanism of action (i.e. they are both acting as traditional agonists at GPR55).

Table 1, below figure 5, shows the finding that CP55.950 not only activates GPR55 at lower concentrations than ∆-9-THC, but also (as expected) shows a similarly increased potency concerning CB1 and CB2 receptors.

So to answer your question, the synthetic cannabinoid analogue CP55.940 seems to show greater activity at GPR55 than ∆-9-THC. In a similar fashion, suggesting no significant interaction statistically, CP55.940 and ∆-9-THC show a similar relationship at the other CB receptors, which they also both show greater affinities for than GPR55.

However, the role of GPR55 in the effects of cannabis is yet to be determined. GPR55 has been shown to be most densely expressed in basal ganglia structures and the putamen, all of which are involved in the execution and coordination of voluntary movement. If GPR55 plays any role in the effects of cannabis, they likely pertain to this arena: voluntary motion, spatial exploration...etc. For now, any role for this new receptor in the effects of cannabis is purely speculative.