EAAT4, a member of the high-affinity Na+/K+-dependent glutamate transporter family, is highly enriched in the Purkinje cells of the cerebellum although not restricted to these cells. The presence of EAAT4 in the adult rat brain was examined immunocytochemically. Despite the moderate expression levels in the forebrain, compared to the cerebellum, EAAT4 was omnipresent throughout the forebrain. The highest expression levels could be observed in the substantia nigra pars compacta, ventral tegmental area, the habenulo-interpeduncular system including the fasciculus retroflexus, the subiculum and the superficial layers of the superior colliculus. RT-PCR on tissue from the fasciculus retroflexus confirmed the unexpected axonal expression of EAAT4 on the mRNA level. Relatively high levels of EAAT4 protein could also be detected in principal cells of the hippocampus, in glutamatergic, GABAergic and most likely also cholinergic cells of all nuclei of the basal ganglia and in neurons of layers II/III and V of the cerebral cortex. Overall, EAAT4 immunoreactivity was confined to soma and dendrites of neurons, with a clear cytoplasmic labeling when tissue was treated to have an optimal permeability. In addition, a very pronounced neuropil staining could be observed in several brain regions.

These data not only prove the presence of EAAT4 protein throughout the rat forebrain, but the high expression level of EAAT4 in the fasciculus retroflexus also suggests that EAAT4, until now commonly known to be a post-synaptic glutamate transporter, is expressed pre-synaptically at habenulo-interpeduncular synapses.
Original languageEnglish
Title of host publication15th Neuropharmacology Conference
Publication statusPublished - 2008
EventFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet - Stockholm, Sweden
Duration: 21 Sep 200925 Sep 2009

Publication series

Name15th Neuropharmacology Conference

Conference

ConferenceFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet
CountrySweden
CityStockholm
Period21/09/0925/09/09

    Research areas

  • EAAT4, forebrain, immunohistochemistry

ID: 1749556