Cannabinoids

Cannabinoid Receptors and Their Ligands: Ligand–Ligand and Ligand–Receptor Modeling Approaches 249

Fig. 1.A helix net representation of the human CB 1 receptor sequence. (Gerard et al. 1991)

Fig. 2.A helix net representation of the human CB 2 receptor sequence. (Munro et al. 1993)

mouse, the CB 2 receptor is much more divergent. Sequence analysis of the coding
region of the rat CB 2 genomic clone indicates 93% amino acid identity between rat
and mouse and 81% amino acid identity between rat and human. CB 2 receptor-
transfected CHO cells exhibit high constitutive activity (Bouaboula et al. 1999).
Evidence for other cannabinoid receptors is mounting in the literature (Breivogel
et al. 2001; Di Marzo et al. 2000; Fride et al. 2003; Jarai et al. 1999; Wagner et al.
1999). However, no new CB receptor subtypes have yet been cloned.