Immunohistochemical localization of phosphorylated AMPA-type glutamate receptors in cerebellar Purkinje cell layer

ABSTRACT

Twenty adult albino rats were used in this work. The skull of each animal was opened carefully to obtain the cerebellum after killing the animal and the vermis was dissected. Each vermis was cut sagittally into many slices [200 mum in thickness]. The cerebellar slices were treated by different chemicals [AMPA, 8-bromo-cGMP and antibody against peptide 12 [12p3]] for 5-30 minutes and one of the protein kinase inhibitors [staurosporine] was added to some cerebellar slices. After a previous chemical treatment, the cerebellar slices were fixed in a suitable fixative for 72 hours before light and electron microscopic preparation and examination. The phosphorylation [staining of Purkinje cell bodies and their dendrites] of AMPA receptors was rapid after exposure to AMPA, but this phosphorylation was transient and disappeared within 20 minutes. 12p3 immunoreactivity in long-term desensitization persisted for more than 30 minutes after its application, which was demonstrated by an immunohistochemical study of Purkinje cells. Protein kinase inhibitor [staurosporine] application abolished the staining of Purkinje cell dendrites due to its inhibitory action. So, phosphorylation of AMPA- type glutamate receptors in Purkinje cell layer of the cerebellum may be used in the potentiation or desensitization of this cell layer