title: The activation of metabotropic glutamate receptors differentially affects GABA and alpha-melanocyte stimulating hormone release from the hypothalamus and the posterior pituitary of male rats.
abstract: The aim of the present study was to investigate the effect of metabotropic glutamate receptor (mGluR) activation on gamma-aminobutyric acid (GABA) and alpha-melanocyte stimulating hormone (alpha-MSH) release from hypothalamic fragments and posterior pituitaries. The actions of a number of subtype-selective mGluR agonists were monitored. A group I mGluR agonist, (S)-3-hydroxyphenylglycine (3-HPG; 0.5 mM), decreased K+-induced hypothalamic GABA release. (RS)-1-Aminoindan-1,5-dicarboxylic acid (AIDA), a specific group I mGluR antagonist (0.2 mM), blocked the effect of 3-HPG. (2S, 1'S, 2'S)-2-(Carboxycyclopropyl) glycine (L-CCG-I) and L-serine-O-phosphate (L-SOP; 0.01-1 mM), agonists of group II and III mGluRs, respectively, did not modify hypothalamic evoked GABA release. Group I mGluR activation decreased, whereas group III increased and group II induced no changes in GABA release from the posterior pituitary. 3-HPG (1 mM) and L-CCG-I (0.1 mM) decreased, whereas L-SOP (0.01-0.1 mM) did not change alpha-MSH release from hypothalamic fragments. No agonists of the three mGluR groups modified alpha-MSH release from the posterior pituitary. These results indicate that activation of mGluRs differentially affects GABA and alpha-MSH release from the hypothalamus and the posterior pituitary.
authors.affiliation: Centro de Investigaciones en Reproducción, Facultad de Medicina, Universidad de Buenos Aires, Piso 10, Buenos Aires, Argentina.
authors.forename: Macarena
authors.initials: M
authors.lastname: Pampillo
authors.forename: Teresa
authors.initials: T
authors.lastname: Scimonelli
authors.forename: Beatriz H
authors.initials: BH
authors.lastname: Duvilanski
authors.forename: María Ester
authors.initials: ME
authors.lastname: Celis
authors.forename: Adriana
authors.initials: A
authors.lastname: Seilicovich
authors.forename: Mercedes
authors.initials: M
authors.lastname: Lasaga
mesh_terms: D000818:Animals; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism*; D007189:Indans / Q000494:pharmacology; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D000521:alpha-MSH / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: C095756:1-aminoindan-1,5-dicarboxylic acid; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D007189:Indans; D018696:Neuroprotective Agents; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; C104077:metabotropic glutamate receptor type 1; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D005680:gamma-Aminobutyric Acid; D000521:alpha-MSH; C023010:4-hydroxyphenylglycine; D005998:Glycine