Decreased MK-801 binding in discrete hippocampal regions of prion-infected mice

The neurochemical alterations associated with neurodegeneration in prion diseases are not well defined. It is therefore of interest to study the influence of prion infection on messenger molecules and their receptors. In the present study we have analyzed the possible involvement of NMDA receptors in prion-infected mice using ligand binding autoradiography and iodinated MK-801, a noncompetitive NMDA antagonist. The results show a reduced binding of MK-801 in discrete regions of hippocampus at 110 days after infection, that is before the appearance of behavioral symptoms. In addition, early transient increases in MK-801 binding were observed in several layers. The exact neuroanatomical correlate of these changes in MK-801 binding, as well as its functional significance in relation to prion symptomatology, remain to be analyzed. (C) 2001 Academic Press.