GABA-A-RECEPTOR IMMUNOREACTIVITY IN THE RAT DORSAL THALAMUS - AN ULTRASTRUCTURAL INVESTIGATION

The ultrastructural localization of GABA(A)-receptor (GABA(A)-R) immun oreactivity (ir) in representative nuclei of the rat dorsal thalamus w as investigated using the monoclonal antibody 62-3G1 to the beta2 and beta3 subunits of the GABA(A)-R [8]. The pattern of distribution and t he subcellular localization of ir were similar in all the thalamic nuc lei examined, with the exception of the reticular nucleus that was unl abeled. The reaction product was present along somatic and dendritic p lasma membranes of thalamic neurons and on their intracellular membran es. No labelling was observed in glial cells. The ir was present in ar eas of plasma membranes related and non related to terminals containin g flat vesicles, and also on invaginated plasma membranes suggesting a recycling process of the receptor complex. The distribution and misma tches between GABA neurotransmitter and its receptor localization are discussed.