COOCCURRENCE OF PERINEURONAL NETS WITH GABA(A) RECEPTOR ALPHA-1 SUBUNIT-IMMUNOREACTIVE NEURONS IN THE RAT SEPTAL REGION

THE immunocytochemical demonstration of the GABA(A) receptor alpha 1 subunit was combined with the Wisteria floribunda agglutinin staining of lattice-like extracellular matrix components-known as perineuronal nets-in the rat basal forebrain. Both were found to be co-localized in the septal-diagonal band region (e.g. in the medial septum, 96%), but only exceptionally in the ventral pallidum (3-10%) and nowhere in other basal forebrain subdivisions. This co-occurrence of perineuronal nets with septo-hippocampal projection neurones-previously characterized as GABAergic-expressing the GABA(A) receptor alpha 1 subunit- as well as parvalbumin-immunoreactivity, suggests the involvement of these intra- and extraneuronal components in the fast spiking neuronal activity essential for the generation and maintenance of hippocampal theta rhythm.