Figure 4.

Schematic diagram showing possible molecular mechanisms for cannabinoid signaling in sweet-sensitive taste cells. Endocannabinoids binding to the cannabinoid receptor (CB₁) activate phospholipase Cβ2 (PLCβ2) via the Gαq pathway. The synergistic or additive activation of PLCβ2 results in enhanced sweet responses in sweet-sensitive taste cells (indicated by red up arrow). Alternatively, the activation of CB₁ suppresses adenylyl cyclase (AC) activity via the Gαi/o pathway, leading to a decrease in [cAMP]_i (indicated by blue down arrow). The reduction in cAMP levels decreases the activity of protein kinase A (PKA), leading to the disinhibition of PLC signaling (indicated by X) and enhanced sweet responses in sweet-sensitive taste cells.