Glutamate transporter EAAC1 in the cat periaqueductal gray matter

The neuron-specific glutamate (Glu) transporter, excitatory amino acid carrier 1 (EAAC1), plays an important role in regulating Glu levels in the synaptic cleft. Using a specific EAAC1 monoclonal antibody, we investigated its regional distribution and ultrastructural localization in cat periaqueductal gray matter. In light microscopy EAAC1 immunoreactivity was randomly distributed to neurons and punctate structures. In electron microscopy, it was observed in the soma of many neurons, dendrites, in a discrete number of axon terminals, in ependymal cells and in few distal astrocytic processes. EAAC1 is thus not restricted to neurons, but could play an important role in glial cells. Moreover, EAAC1 protein could participate both in regulating the action of the Glu released at synaptic level and in other aspects of Glu metabolism.