Figure 1.

Effects of opioid agonists on pain and signal transduction. Abbreviations: ATP, adenosine triphosphate; ADP, adenosine diphosphate; GABA, gamma-aminobutyric acid; AMP, adenosine monophosphate; cAMP, cyclic adenosine monophosphate; PKA, protein kinase A; CRE, cAMP-responsive element; CREB, cAMP-responsive element binding protein; GTP, Guanosine triphosphate; GDP, Guanosine diphosphate; PDEs, Cyclic nucleotide phosphodiesterases; Ca2+/CaMK-II, Ca2+/calmodulin-dependent protein kinase II. Symbols: solid arrow, strong activation; dashed arrow, moderate activation; solid T-shaped line, strong inhibition; dashed T-shaped line, moderate inhibition, line with ×, blocking; upward arrow, increased effect; downward arrow, decreased effect. The figure was made with www.biorender.com (accessed on 19 October 2021).