N-methyl-D-aspartate receptor involvement in dexamethasone and stress-induced hypothalamic somatostatin release in rats.
The median eminence (ME) push-pull perfusion technique was used in this work and the results clearly showed that i.p. administration of MK-801 (4 mg/kg), a specific N-methyl-D-aspartate (NMDA) receptor antagonist, totally abolished dexamethasone (Dex) (300 micrograms/ 100 g i.p. injected) and immobilization stress-induced hypothalamic somatostatin release in adult male rats. We also observed that glutamate from median eminence-hypothalamic medio basal (ME-MBH) complex, measured by high performance liquid chromatography (HPLC), exhibited a conspicuous secretory pattern, with the total amount released not modified by Dex administration. This indicates that Dex and stress-induced somatostatin (SS) secretion is not mediated by endogenous glutamate variations but likely by activation of NMDA receptors.
Estupina
C
C
Laboratoire Plasticite et Adaptation Cellulaires, ERS 5644 du CNRS, Université Montpellier 2, France.
Abarca
J
J
Arancibia
S
S
Belmar
J
J
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003907:Dexamethasone / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007103:Immobilization; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D013004:Somatostatin / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism*
D016194:Receptors, N-Methyl-D-Aspartate; D013004:Somatostatin; D016291:Dizocilpine Maleate; D003907:Dexamethasone