Recombinant α1β2γ2 GABAA receptors expressed in HEK293 and in QT6 cells show different kinetics

Neuronal gamma-aminobutyric acid (GABA)(A) receptors are extremely heterogeneous and therefore GABAergic currents represent responses of unknown mixture of receptor subtypes. Expression of recombinant receptors in foreign cells allows to investigate a defined receptor subtype but its properties can be altered due to, e.g., differences in the endogenous modulators. In the present study the alpha1beta2gamma2 receptors were expressed in HEK293 and QT-6 cells and current responses to ultrafast GABA applications were recorded. Rise time and rapid deactivation component were faster in responses recorded from QT-6 cells. Moreover, in QT-6 cells desensitization was faster and more profound. Recovery in the paired pulse experiments was faster in HEK293 cells. In conclusion, we provide evidence that recombinant receptors may show functional differences when expressed in different cells. (C) 2003 Elsevier Ireland Ltd. All rights reserved.