Page 20 - Q. Neuroscience

[Q. Neuroscience-11]

Inhibitory effects of Metergoline on Nav1.2 voltage-

dependent sodium channel

Junho Lee¹

¹Biotechnology, Chonnam National University, Gwangju 61186, Korea

Metergoline is an ergot-derived psychoactive drug that acts as a ligand for serotonin and dopamine receptors. In
the present study, we investigated the effects of metergoline on neuronal Nav1.2 voltage-dependent sodium
channel activity. The two-microelectrode voltage clamp technique was used to study the regulation of metergoline

on Na+ current in Xenopus oocytes expressing cRNA-encoding Nav1.2 α and β1 subunits in the rat brain. In oocytes

that expressed neuronal Na+ channels, metergoline induced inhibitory effects on the peak of Na+ currents. The
metergoline-induced tonic inhibitions of peak Na+ currents were voltage- and concentration-dependent and
reversible. The half maximal inhibitory concentration (IC50) in peak currents of rat brain Na1.2 channels was 4.6 ±

1.3 uM. Metergoline treatment produced a 3.6 ± 0.4 mV depolarizing shift in the activation voltage but did not
alter the steady-state inactivation voltage. In addition, metergoline produced a use-dependent blockade of the Na+

channel after high-frequency stimulation, indicating that metergoline could exert an inhibitory effect on the open
state of the Na+ channel. Taken together, these results indicate that metergoline might regulate neuronal Nav1.2

voltage-dependent channels that are expressed in Xenopus oocytes.