8-Bromo-cAMP blocks opioid activation of a voltage-gated potassium current in isolated hippocampal neurons

We have previously shown that μ-selective opioid agonists activate both an inward rectifying and a voltage-gated potassium conductance in acutely dissociated non-pyramidal neurons from rat hippocampus. We now report that the opioid-activated voltage-gated potassium conductance was blocked by the membrane permeable cAMP analogue 8-bromo-cAMP. In contrast, 8-bromo-cGMP failed to inhibit opioid activation of the voltage-gated potassium current. These results suggest that the opioid-activated potassium channels is regulated by cAMP-dependent phosphorylation.