Systemic injection of epinephrine or insulin in chicks increased both, by different mechanisms, the GABAA receptor density in the synaptosomal membrane surface.

MARIANA PAULA, CID; SALVATIERRA, NANCY ALICIA; ARCE AUGUSTO,

PINAMAR, Buenos Aires, Argentina

Congreso; SAIB, PABMB AND SAN MEETING; 2005

SYSTEMIC INJECTION OF EPINEPHRINE OR INSULIN IN CHICKS INCREASED BOTH, BY DIFFERENT MECHANISMS, THE GABAA RECEPTOR DENSITY IN THE SYNAPTOSOMAL MEMBRANE SURFACE Mariana Paula Cid, Nancy Alicia Salvatierra and Augusto Arce Cátedra de Química Biológica, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba Email: macccid@arnet.com.ar   ABSTRACT The [3H]-flunitrazepam receptor density measured ex vivo in the synaptosomal membranes surface at 4 ºC was recruited by acute stress of chicks possibly  through the phosphorylation of the GABAA receptors and/or their associated proteins. A systemic injection of epinephrine at 0.25 mg and 0.5 mg/kg of body weight increased the GABAA receptor expression in synaptosomes in a stress dependent way and in addition to the increase induced by stress. No changes were observed with propranolol. In the other hand, insulin at different doses increased the receptor density in non-stressed but not in the stressed chicks suggesting that insulin induced the recruitment of receptors, which is a different mechanism than occurs by the epinephrine. The results suggest that both epinephrine and insulin increased the GABAA receptors by a recruitment of receptors depending of the previous phosphorylation of the GABAA receptors and/or their associated proteins.