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Titolo:
Ionotropic glutamate receptors trigger microvesicle-mediated exocytosis ofL-glutamate in rat pinealocytes
Autore:
Yatsushiro, S; Yamada, H; Hayashi, M; Yamamoto, A; Moriyama, Y;
Indirizzi:
Okayama Univ, Fac Pharmaceut Sci, Dept Biochem, Okayama 7008530, Japan Okayama Univ Okayama Japan 7008530 Dept Biochem, Okayama 7008530, Japan Japan Sci & Technol Corp, CREST, Tokyo, Japan Japan Sci & Technol Corp Tokyo Japan Technol Corp, CREST, Tokyo, Japan Kansai Med Univ, Dept Physiol, Moriguchi, Osaka 570, Japan Kansai Med Univ Moriguchi Osaka Japan 570 ol, Moriguchi, Osaka 570, Japan
Titolo Testata:
JOURNAL OF NEUROCHEMISTRY
fascicolo: 1, volume: 75, anno: 2000,
pagine: 288 - 297
SICI:
0022-3042(200007)75:1<288:IGRTME>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
MELATONIN SYNTHESIS; NMDA RECEPTOR; CHEMICAL TRANSDUCTION; FUNCTIONAL EXPRESSION; MOLECULAR DIVERSITY; CA2+ PERMEABILITY; NERVOUS-SYSTEM; AMPA SUBTYPE; CLONED CDNAS; SUBUNIT;
Keywords:
ionotropic glutamate receptor; pinealocytes; exocytosis; synaptic-like microvesicle; L-glutamate; L-type Ca2+ channel;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Moriyama, Y Okayama Univ, Fac Pharmaceut Sci, Dept Biochem, Okayama 7008530, Japan Okayama Univ Okayama Japan 7008530 m, Okayama 7008530, Japan
Citazione:
S. Yatsushiro et al., "Ionotropic glutamate receptors trigger microvesicle-mediated exocytosis ofL-glutamate in rat pinealocytes", J NEUROCHEM, 75(1), 2000, pp. 288-297

Abstract

Rat pinealocytes receive noradrenergic innervation that stimulates melatonin synthesis. Besides melatonin, we showed previously that pinealocytes accumulate L-glutamate in microvesicles and secrete it through an exocytic mechanism. The secreted glutamate binds to the class II metabotropic glutamatereceptor and inhibits norepinephrine-stimulated melatonin synthesis in neighboring pinealocytes through an inhibitory cyclic AMP cascade. In this study, it was found that, in addition to metabotropic receptors, pinealocytes express functional ionotropic receptors. RT-PCR and northern analyses indicated the expression of mRNA for GluR1, KA2, and NR2C in pineal gland. The presence of GluR1 protein was confirmed by immunological techniques, but neither KA2 nor NR2C was detected. Consistent with this observation, the presence of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or kainate, non-N-methyl-D-aspartate receptor agonists, transiently stimulated increased the intracellular Ca2+ concentration of cultured pinealocytes, whereas N-methyl-D-aspartate did not. These responses were prevented by 6-cyano-7-nitroquinoxaline-2,3-dione, a selective antagonist for non-N-methyl-D-aspartate receptors, by L-type Ca2+ channel blockers such as nifedipine, or by omitting Ca2+ or Na+ in the medium. In the presence of Ca2+ and Na+, (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxarolepropionic acid or kainate evokedglutamate secretion from the cultured cells, which was prevented by 6-cyano-7-nitroquinoxaline-2,3-dione, L-type Ca2+ channel blockers, type E or B botulinum neurotoxin, or incubation at <20 degrees C. These results stronglysuggest that GluR1 is functionally expressed in pinealocytes and triggers microvesicle-mediated exocytosis of L-glutamate via activation of L-type Ca2+ channels. It is possible that GluR1 participates in a signaling cascade that enhances and expands the L-glutamate signal throughout the pineal gland.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 07:18:28