Fast desensitization of glutamate activated AMPA/kainate receptors in rat thalamic neurones

An essential part of the excitatory afferent input to the thalamus is mediated by glutamate receptors of the AMPA/kainate type. In contrast to other regions of the mammalian CNS, the biophysical properties of these receptors have not been investigated in thalamic neurones. Using a fast transmitter application system we studied L-glutamate activated currents of cultured neurones in the whole cell and outside-out patch configuration. Current-voltage relationships and dose-response curves of whole cell recordings were in close correspondence to results obtained from other brain areas. Analysis of outside-out patch currents revealed two types of desensitization time constants of 3.0 and 10.2 ms, with the former close to the time constant of decay of miniature glutamatergic synaptic currents.