Differential expression of alfa1 subunit and beta2-3 subunit of GABA-A receptors in neonatal chick forebrain submitted to an acute stress. Modulation by noradrenaline chicks forebrain.

RIBERI M.I,; CID M.P ; SALVATIERRA N.A.

Congreso; IIIRCN, Third joint meeting of the argentine society for neurosciences (SAN) and the argentine workshop in neurosciences (TAN).; 2011

Gamma-aminobutiric acid, the mayor inhibitory neurotransmitter in the brain, mediates inhibition via GABAA receptors (GABAAR). The GABAAR consists of five subunits (á, â, ã, ä, å, è, and ð) and the assembly of different combinations of subunits allows the construction of different types of GABAAR, each having specific functional and pharmacological properties. The majority of GABAAR are composed of two á subunits, two â subunits, and one ã subunit. The á1 subunit is associated with pre- and post-synaptic sites, while â subunit is associated only with post-synaptic sites. Our previous findings, in 4-6-day-old chicks, showed differences on behavioral responses and on GABAAR recruitment after Open Field and/or central administration of noradrenaline. In the present report, different doses of noradrenaline (0.0025, 0.0100, 0.0500, 1.000 ug/ul) injected before Open Field induced a differential expression of á1- and â2-3-subunits of GABAAR on cell-surface, detected by immunoperoxidase, in brain tissue. We observed that the á1 subunit has a higher Optical Density due to increased number of labeled cells compared to â2-3 subunits. These results indicated that the differences observed between expressions of both subunits corresponded to an increase in the postsynaptic subunits expression.