Immunolesioning of glutamate receptor GluR1-containing neurons in the rat neostriatum using a novel immunotoxin

Purification and characterization of Luffin P1, a ribosome-inactivating peptide from the seeds of Luffa cylindrica

A peptide designated Luffin P1 was purified from the seeds of Luffa cylindrica. Its molecular mass was determined to be 5226.1 Da by MALDI-TOF MS analysis. The purified Luffin P1 shows a strong inhibitory activity on protein synthesis in the cell-free rabbit reticulocyte lysate with IC(50) of 0.88 nM. Its reaction mechanism is the same as that of the ribosome-inactivating protein trichosanthin, which is an rRNA N-glycosidase. Besides, the results of gel filtration chromatography suggested the existence of polymers of Luffin P1 and polymerization of Luffin P1 enhanced its rRNA N-glycosidase activity. Luffin P1 was the smallest peptide yet reported that has translational inhibitory activity. The cDNA and deduced amino acid sequence of Luffin P1 has also been determined.

Co-localization of AMPA-type glutamate receptor immunoreactivity in neurons of the rat subthalamic nucleus

In order to determine the precise cellular localization of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA)-type glutamate receptor subunit immunoreactivity in the rat subthalamic nucleus, single and double immunofluorescence was performed. Intense level of GluR1, GluR2, GluR2/3 and GluR4 immunoreactivity was found in almost all neurons of the subthalamic nucleus. By double immunofluorescence, the subthalamic neurons in the same sections that displayed a strong immunoreactivity for GluR1 were found to display a robust GluR2 immunoreactivity and the subthalamic neurons that displayed GluR2 immunoreactivity were also found to express GluR4 immunoreactivity. The present results thus demonstrate that individual neurons of the subthalamic nucleus are likely to co-express GluR1 and GluR2, and GluR2 and GluR4 immunoreactivity. The native AMPA channels in the subthalamic neurons may, therefore, be composed of heteromeric subunits. The present results provide information of the neuroanatomical localization of AMPA receptor subunits in neurons of the subthalamic nucleus. The localization of AMPA receptor subunits may be related to functional characteristics of AMPA channels in the subthalamic neurons.