AMPA receptors (AMPARs) are ionotropic glutamate receptors. Their subunits (GluR1-GluR4) form tetrameric assemblies with properties crucially depending on their composition. In particular, AMPARs lacking GluR2 subunit are permeable to Ca²⁺ ions. Furthermore, there is accumulating evidence that AMPARs are modulated by interaction with Transmembrane AMPAR Regulatory Proteins (TARPs). Up to now, six mammalian TARPs have been identified, called gamma 2 to gamma 5, gamma 7 and gamma 8.

Although it has recently been shown that AMPA receptor antagonists are able to limit tumor growth, the role AMPA receptors play in these cells is poorly understood. Using the electrophysiological patch-clamp technique we examined whole cell currents elicited by fast application of AMPAR agonists on tumor cell lines which express different AMPAR subunits as well as different TARPs. At holding potentials between -60 and -100 mV agonist application led to an inward current showing a clear desensitization in most of the cells. The mean single channel conductances of the elicited currents between -11 and -27 pS were estimated by noise analysis. In some cell lines we were not able to measure an AMPAR gated current under our experimental conditions, although AMPAR subunits were identified by rt-PCR. Our results might contribute to understand the role of AMPARs in tumor cells and their TARP specific modulation in a native system.