Effect of naloxone on the secretion of corticosterone induced by gamma-hydroxybutyric Acid in male rats.
Abstract The effect of intraperitoneally administered gamma-hydroxybutyrate on the hypothalamo-hypophysial-adrenocortical axis was studied. A significant increase in plasma corticosterone was induced by the administration of gamma-hydroxybutyrate (100 mg/kg). The lack of antagonism of this action of gamma-hydroxybutyrate by picrotoxin or bicuculline pretreatments (GABAergic antagonists), suggests independence from the GABAergic system. Neither dopaminergic nor serotoninergic systems intervened in the gamma-hydroxybutyrate-stimulating effect on the hypothalamo-hypophysial-adrenocortical axis. Both corticosterone release and synthesis in adrenocortical cells was not significantly affected by gamma-hydroxybutyrate, suggesting that this is possibly due to a central action of gamma-hydroxybutyrate. The increase in corticosterone levels was probably mediated by an opioid receptor, since a strong similarity existed between the effects of gamma-hydroxybutyrate and those of morphine. Moreover, the results show that the opioid-receptor involvement was demonstrated by the naloxone-sensitivity of the gamma-hydroxybutyrate effects.
Miguez
M I
MI
Department of Physiology, Faculties of Pharmacy, University of Santiago de Compostela, Spain.
Aldegunde
M
M