An Immunohistochemical Study of N-Methyl-D-Aspartate Receptors in Human Cerebellum and Hippocampus

Abstract

The aim of our investigation was to demonstrate the wide distribution of glutamate N-methyl-D- aspartate receptors (NMDA R), particularly the not-widely investigated 2A and 2B subunits, in the human adult cerebellum and hippocampus. Specimens of human hippocampus and cerebellum were obtained at the time of autopsy from two male individuals, aged 24 and 48 years, with no obvious brain injury. The brains were immunostained using anti-human rabbit polyclonal NR antibodies (NMDA R 2A&B, AB1548 (Chemicon), NMDA receptors anti- human Poly HRP IHC (Detection kit) and counterstained with Mayer's hematoxylin. The present immunohistochemical research of human adult cerebellum and hippocampus demonstrates that the majority of neurons in the dentate gyrus, the large pyramidal neurons of the hippocampus, the granular cells of the cerebellum as well as the main cerebellar neuron, namely Purkinje cell, stained deeply by the monoclonal antibody, suggesting that the majority of the neuronal network in cerebellum and hippocampus uses as neurotransmitter the excitatory aminoacids on the system of NMDA receptors. Our findings, demonstrating that the majority of cells were stained by the monoclonal antibody, emphasize the importance of the excitatory system of the glutamate and the examined receptors 2A & B, in the human cerebellum and hippocampus in adults, underlying the important role that this system may play in memory function and cognition, and at the same time the crucial role of the cerebellum in higher cognitive functions, in part due to the wide distribution of NMDA R.