Neurosteroids and GABAergic activity on lateral septum.

GARCÍA S.; NANFARO F.; AGASSO A.; CABRERA R.; YUNES R

Córdoba

Congreso; XXIX Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias.; 2014

Sociedad Argentina de Investigación en Neurociencias

NEUROSTEROIDS AND GABAERGIC ACTIVITY ON LATERAL SEPTUM Lateral septal nucleus, which can be divided into dorsal, intermediate and ventral parts, receives its major input ?a glutamatergic one? from the hippocampal formation and projects a GABAergic output to the medial septal. GABAergic neurons are one of the most frequent neuronal types present in the lateral septum of the rat?s brain. Their activity could potentially affect learning and memory performance, among others. The aim of this work was to study whether pregnenolone and pregnenolone sulphate can modify GABA release. Lateral septum, according to the experimental group, was microinjected with 1μl of either: 1) saline; 2) pregnenolone 12μM; and 3) pregnenolone sulphate 12μM. GABA concentration, our output, was measured by dynamic superfusion (briefly, slices of brain tissue are incubated with [H3]GABA, and then its release is chemically elicited by a solution of K+ 28mM. Finally, [H3]GABA is measured by a beta counter). Our results showed that pregnenolone sulphate increased GABA release while in contrast pregnenolone had no effect regarding control group values. Since previous evidence from our lab showed different memory performance according to the neurosteroid and the behavioral paradigm utilized (i.e. appetitive vs aversive), it is possible to think that ?at least in part? the difference reported here could be attributed to the sulphonation state of the neurosteroid, as a sort of putative molecular switch.