FIGURE 1.

Cross-talk between receptors by dimerization. The 5-HT2A receptor mediated hallucinogen-specific intracellular pathway requires the dimerization of the 5-HT2A receptor with the mGlu2 receptor. This unique (G protein-coupled) pathway is associated only with the dimer and not activated by either receptor alone. Serotonin lacks the mGlu2 receptor binding feature and the psychotropic effects of hallucinogens are abolished by the elimination of the mGlu2 receptor. The 5-HT2A-mGlu2 dimer is the prime target of some serotonergic hallucinogens (Moreno et al., 2011).