GABA TRANSPORTER-1 (GAT-1) IMMUNOREACTIVITY IN THE CAT PERIAQUEDUCTALGRAY-MATTER

Using light- and electron-microscopic immunocytochemistry, we investig ated the regional distribution and the ultrastructural localization of GAT-1, a prominent GABA transporter, in the cat FAG. Light microscopi c observations indicate that GAT-1-immunoreactive elements are particu larly dense in PAG-DL and form a pair of longitudinal columns extendin g in the intermediate region of this structure. At electron-microscopi c level, GAT-1 immunoreactivity was present in axon terminals forming symmetric synapses and in the distal processes of astroglial cells. Th ese data further confirm the existence of longitudinal columns within FAG. They also indicate that GAT-1 could influence the action of GABA on its receptors, probably regulating the magnitude and duration of GA BA's synaptic action on FAG neurons, and suggest that astrocytes may p lay an important role in this process. (C) 1998 Elsevier Science Irela nd Ltd. All rights reserved.