EN
Cell culture is a convenient model for pharmacokinetic studies, but during the culture period, GABAa receptors are likely to undergo different modulatory processes. In this study, the current responses to ultrafast GABA applications were recorded from patches excised from neurons cultured for either up to two days (short-term culture) or for more than two weeks (long-term culture). The dose-dependencies of the currentrising phases revealed significant differences between the two groups. In the short-term cultures, the responses to both saturating and non-saturating GABA concentrations were slower than in the case of the long-term cultures. We conclude that the GABAa receptors in cultured neurons undergo profound kinetic changes involving the modulation of the binding reaction and transitions between bound states.