Depletion of Glutamate Receptor Glur2-Immunoreactive Neurons in the Rat Neostriatum by Immunolesioning

Glutamate is the major excitatory neurotransmitter in the basal ganglia, a group of subcortical nuclei that is associated with movement. The function of glutamate is mediated by different classes of glutamate receptors. In order to investigate the localization and receptor physiology of the GluR2 subunit of the a-amino-3-hydroxy-5-methyI-4-isoazole propionic acid (AMPA)-type glutamate receptor in the neostriatum, the principle region in the basal ganglia, immunolesioning was performed using an indirect immunotoxin (Kwok et al. [1997] Soc. Neurosci. Abr. 23, 188). The immunotoxin was produced by conjugating a commercially available anti-GluR2 antibody with a ribosome-inactivating protein, trichosanthin. Results of the present study showed that there was no obvious adverse effect observed in the motor functions of the rats after unilateral intraventricular or intrastriatal injections of the anti-GIuR2 immunotoxin. In those striatal sections obtained from the lesioned rats, a depletion in numbers of the GluR2-immunoreactive neurons was found in the neostriatum, whilst immunoreactivity for GluR2 was primarily found in the perikarya medium-sized spiny neurons of the nonlesioned side. These results indicate that immunolesioning is a useful tool in selective cell killing experiments and may provide physiological implications ofthe of GluR.2 receptor functions in the neostriatum.