Transient Increase of AMPA and NMDA Receptor Binding in the Barrel Cortex of Mice after Tactile Stimulation

Abstract The effects of sensory stimulation and sensory conditioning upon [ 3 H]MK-801 [(+)-5-methyl-10,11-dihydro- 5H-dibenzo[a,d]cyclohepten-5,10-imine] binding to N -methyl- d -aspartate (NMDA) receptor sites and [ 3 H]AMPA (α-amino-3-hydroxy-5-methylisoxasole-4-propionic acid) binding to AMPA receptor sites were examined in the primary somatosensory (SI) cortex of mice. Following short-lasting unilateral tactile stimulation of a selected row of vibrissae, and tactile stimulation paired with noxious stimulus (the pairing procedure was found to alter cortical representation of vibrissae), in vitro receptor binding autoradiography was performed on the sections of the barrel cortex of mice. One hour after the end of tactile stimulation or training procedure there was an increase of [ 3 H]MK-801 and [ 3 H]AMPA binding in the corresponding row of barrels in layer IV of the SI cortex of adult mice. These effects disappeared 24 h after the end of each experimental procedure. The results suggest that both subtypes of glutamate receptors are regulated in an activity-dependent way and that sensory stimulation transiently modifies local cortical processing.