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Titolo:
CYCLOTHIAZIDE AND AMPA RECEPTOR DESENSITIZATION - ANALYSES FROM STUDIES OF AMPA-INDUCED RELEASE OF [H-3]-NORADRENALINE FROM HIPPOCAMPAL SLICES
Autore:
COWEN MS; BEART PM;
Indirizzi:
MONASH UNIV,DEPT PHARMACOL CLAYTON VIC 3168 AUSTRALIA MONASH UNIV,DEPT PHARMACOL CLAYTON VIC 3168 AUSTRALIA
Titolo Testata:
British Journal of Pharmacology
fascicolo: 3, volume: 123, anno: 1998,
pagine: 473 - 480
SICI:
0007-1188(1998)123:3<473:CAARD->2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
DEPENDENT PROTEIN-KINASE; GLUTAMATE-RECEPTOR; KAINATE RECEPTORS; REGULATING RECEPTORS; CULTURED NEURONS; NITRIC-OXIDE; PATCH-CLAMP; NMDA; ACID; -DIHYDROXY-6-NITRO-7-SULFAMOYL-BENZO(F)QUINOXALINE;
Keywords:
AMPA HA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONATE) RECEPTOR; CYCLOTHIAZIDE; DESENSITIZATION; RELEASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
33
Recensione:
Indirizzi per estratti:
Citazione:
M.S. Cowen e P.M. Beart, "CYCLOTHIAZIDE AND AMPA RECEPTOR DESENSITIZATION - ANALYSES FROM STUDIES OF AMPA-INDUCED RELEASE OF [H-3]-NORADRENALINE FROM HIPPOCAMPAL SLICES", British Journal of Pharmacology, 123(3), 1998, pp. 473-480

Abstract

1 Responses in brain produced by the activation of the pha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) subtype of ionotropic receptor for L-glutamate are often rapidly desensitizing. AMPA-induced desensitization and its characteristics, and the potentiating effect of cyclothiazide were investigated in vitro by analysing AMPA-induced release of [H-3]-noradrenaline from prisms of rat hippocampus. 2 AMPA (1-1000 mu M) stimulated the release of [3H]-noradrenaline in a concentration-dependent manner that was both calcium-dependent and tetrodotoxin-sensitive, and attenuated by the AMPA-selective antagonists, NBQX (1 and 10 mu M), LY 293558 (1 and 10 mu M) and GYKI 52466 (10 and 30 mu M). 3 By use of an experimental procedure with consecutive applications of AMPA (100 mu M, 28 min apart), the second response was reduced, indicative of receptor desensitization, and was reversed by cyclothiazidein a concentration-dependent manner (1-300 mu M). The concentration-response curve for AMPA-induced release of [H-3]-noradrenaline was shifted leftwards, but the reversal by cyclothiazide of the desensitized response was partial and failed to reach the maximal response of the first stimulus. 4 Observations made with various schedules of cyclothiazide application indicated that the initial AMPA-evoked response was already partially desensitized (150% potentiation by 100 mu M cyclothiazide) and that the desensitization was not likely to be due to a time-dependent diminution and was longlasting (second application of cyclothiazide was ineffective). 5 Go-application of a number of drugs with actions on second messenger systems, in association with the second AMPAstimulus, revealed significant potentiation of the AMPA-induced release of [H-3]- noradrenaline: forskolin (IO mu M, +78%), Rp-cAMPS (100 mu M, +65%), Ro 31-8220 (10 mu M, + 163%) and thapsigargin (100 mu M, 161%). 6 The AMPA receptor-mediated response regulating the release of [H-3]-noradrenaline from rat hippocampal slices was desensitized andcyclothiazide acted to reverse partially the desensitization in a concentration-dependent manner. Since the time-course of desensitization was longer lasting than that noted in previous electrophysiological studies, multiple events may be involved in the down-regulation of AMPA receptor activity including receptor phosphorylation and depletion of intracellular Ca2+ stores.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/08/20 alle ore 18:51:06