Effects of okadaic acid on voltage-gated potassium and calcium channels in cultured rat trigeminal neurons / 中国药理学与毒理学杂志

ABSTRACT

AIM To investigate the effects of serine/threonine protein phosphatases in regulation of cell signal transduction on voltage-gated potassium and calcium channels in cultured rat trigeminal ganglion (TRG) neurons. METHODS Whole-cell patch clamp technique was used to record the potassium and calcium currents from adult rat TRG neurons before and after perfusion of okadaic acid, a potent inhibitor of the serine/threonine protein phosphatases 1 and 2A. RESULTS Okadaic acid 1 μmol·L-1 inhibited transient outwards potassium currents (IA) by 28.6%, increased delay rectified potassium currents (IK) and calcium currents (ICa) by 22.7% and 20.0%, respectively. okadaic acid 1 μmol·L-1 produced significant hyperpolarizing shifts in the conductance-voltage (G-V) curves and inactivation curves of IA , also produced significant hyperpolarizing shifts in the G-V curves of IK, while it had no effect on the activation and inactivation kinetics of ICa. CONCLUSION Serine/threonine protein phosphatases 1 and 2A may be involved in the modulation of voltage-gated potassium and calcium channels on rat TRG neurons. In addition, voltage-gated potassium and calcium channels show different dependence on the dephosphorylation reactions of PP1 and PP2A phosphatases.