Figure 3.

Cannabinoid agonist WIN-55,212-2 (WIN) activated inwardly rectifying potassium currents in oocytes co-expressing GIRK1/2 + RGS4 with CB1. Currents were induced by exchanging ND96 with HK while the oocytes were voltage-clamped at −90 mV. Current enhancement observed on application of 0.5 μM WIN in the presence of HK. In the final, oocytes were perfused with ND96. The experiment was repeated in at least 4 oocytes. In the case of CB2, a similar approach is followed. ND96: physiological salt buffer solution (96 mM NaCl, 2 mM MgCl₂, 2 mM KCl, 5 mM HEPES, and 1.8 mM CaCl₂, with a final pH of 7.5), HK: high potassium solution for the measurement of K⁺ currents through GIRK1/2 channels (96 mM KCl, 2 mM NaCl, 1 mM MgCl₂, 1.8 mM CaCl₂, 5 mM HEPES with a final pH of 7.5).