“La administración sistémica de epinefrina induce una exposicion de receptores GABAA en sinaptosomas de cerebro anterior de pollos, en forma aditiva al inducido por un estrés agudo.”

CID M.P., SALVATIERRA N.A. Y ARCE A.

Mar del Plata, Bs. As., Argentina.

Congreso; Congreso Conjunto de Sociedades Biomédicas,; 2004

CID M.P., Salvatierra N.A. and Arce A. THE SYSTEMIC ADMINISTRATION OF EPINEPHRINE INDUCES A RECRUITMENT OF GABAA RECEPTORS IN ADDITION TO STRESS IN CHICK FOREBRAIN Química Biológica, Facultad Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Av. Vélez Sarsfield 1611 (X5016GCA) Córdoba. nsalvatierra@com.uncor.edu   The release of the adrenal stress hormone, epinephrine, is a peripheral physiological response initiated by exposure to novel events. This capacity to affect to memory formation has been attributed in a large part to the actions of this hormone in potentiating norepinephrine realease within CNS. Behavioural and pharmacological studies suggest a relationship between noradrenergic and GABAergic system. Furthermore, the stress by partial immersion in water, in chicks, induces a recruitment of GABAA receptor (RGABAA). The aim was to evaluate the possible effect of systemic administered epinephrine on recruiment of RGABAA. Ten days-old chicks were distributed in groups, Group 1, Group 2 and Group 3, injected with saline, epinephrine 0,25 and 0,50 mg/kg of body weight, respectively. Subsequently, each group was stressed, as above mentioned, during 15 min. Immediately later, they were sacrificed, the cerebral hemispheres dissected, the crude synaptosomal fraction obtained, and maximum density of [3H]-flunitrazepam was determined. The Bmax increased compared to control (not stressed), 27% (P <0,01), 44% (P <0,01) and 79% (P <0,01) in each group respectively. In chicks stressed, the epinephrine induced an increase of the 13% (P <0,01) between Groups 1 and 2, and, of the 12% (P <0,01) and of the 25% (P <0,01) between Group 3 and Groups 2 and 1, respectively. The results suggests that the RGABAA increment by epinephrine would be due to a different mechanism than the increase induced by acute stress.