14 R.G. Pertwee
Fig. 5.The structures of four nonclassical cannabinoids
– Nonclassical cannabinoids consist of bicyclic and tricyclic analogues of∆^9 -THC
that lack a pyran ring; examples include CP55940, CP47497, CP55244 and HU-
308 (Fig. 6). They are, therefore, closely related to the classical cannabinoids.- Incontrast,theaminoalkylindolegroupofcannabinoidreceptoragonists(Fig.7)
have structures that are completely different from those of other cannabinoids.
Indeed, results from experiments performed with wild-type and mutant CB 1
receptors (Chin et al. 1998; Petitet et al. 1996; Song and Bonner 1996; Tao and
Abood 1998) suggest thatR-(+)-WIN55212 (WIN55212-2), the most widely
investigated of the aminoalkylindoles, binds differently to the CB 1 receptor
than classical, nonclassical or eicosanoid cannabinoids, albeit it in a man-
ner that still allows mutual competition betweenR-(+)-WIN55212 and non-
aminoalkylindole cannabinoids for binding sites on the wild-type receptor. - Membersoftheeicosanoidgroupofcannabinoidreceptoragonistshavemarked-
ly different structures both from the aminoalkylindoles and from classical and
nonclassical cannabinoids. Important members of this group are the endo-
cannabinoids,arachidonoylethanolamide(anandamide),O-arachidonoylethan-
olamine (virodhamine), 2-arachidonoyl glycerol and 2-arachidonyl glyceryl