Figure 2.

Cannabinoid CB1 receptor structure and signaling. (A) Structural model of the CB1 receptor (CB1R)-G_i protein complex obtained from cryoelectron microscopy. The binding site for MDMB-FUBINACA (FUB) is indicated by the magenta SC structure. The CB1-G_i receptor complex structure was obtained from the Protein Data Bank (code 6N4B). (B) Binding of SCs to the CB1 receptor stimulates both neuronal G_i/G_o and β-arrestin signaling pathways (see text for description). In addition, activation of inotropic transient receptor potential (TRP) channels by cannabinoids causes Ca²⁺ influx into the neuron.