INVESTIGADORES
CID Mariana Paula
artículos
Título:
Acute stress or systemic insulin injection increases flunitrazepam sensitive-GABAA receptor density in synaptosomes of chick forebrain: Modulation by systemic epinephrine
Autor/es:
CID MARIANA PAULA; ARCE AUGUSTO; SALVATIERRA NANCY ALICIA
Revista:
STRESS
Editorial:
TAYLOR & FRANCIS LTD
Referencias:
Año: 2008 vol. 11 p. 101 - 107
ISSN:
1025-3890
Resumen:
Interactions between acute stress and systemic insulin and epinephrine on GABAA receptor density in the forebrain were
studied. Here, 10 day-old chicks were intraperitoneally injected with insulin, epinephrine or vehicle and then immediately
stressed by partial water immersion for 15 min and killed by decapitation. Non-stressed controls were similarly injected, then
returned to their rearing boxes for 15 min and then killed. Forebrains were dissected and GABAA receptor density was
measured ex vivo in synaptosomes by 3[H]-flunitrazepam binding assay. In non-stressed chicks, insulin at 1.25, 2.50 and
5.00 IU/kg of body weight (non-hypoglycemic doses) increased Bmax by 33, 53 and 44% compared to saline, respectively.
A similar increase of 41% was observed in receptor density after stress. However, the insulin effect was not additive to the
stress-induced increase suggesting that both effects occur through similar mechanisms. In contrast, epinephrine, at 0.25 and
0.5 mg/kg did not induce any changes in Bmax in non-stressed chicks. Nevertheless, after stress these doses increased the
receptor density by about 13 and 27%, respectively. Similarly, the same epinephrine doses co-administered with insulin
(2.50 IU/kg), increased the receptor density by about 20% compared to insulin alone. These results suggest that systemic
epinephrine, perhaps by evoking central norepinephrine release, modulates the increase in forebrain GABAA receptor binding
induced by both insulin and stress.