L-glutamate inhibition of an inward potassium current in neonatal neurons from the nucleus of the solitary tract.

Neurons isolated from the nucleus of the solitary tract (NTS) of 1- to 4-day-old rats were cultured for a study of the glutamatergic responses in this region of the medulla. Whole cell currents were examined under voltage clamp after 6-14 days in culture. An inwardly rectifying potassium current was identified in 107/174 cells. The presence of this K+ current diminished with time in culture from greater than 80% of the cells at day 6 to less than 30% of the cells after day 10. The current was inhibited by L-glutamate (IC50 = 10 microM).