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Titolo:
Melatonin generates an outward potassium current in rat suprachiasmatic nucleus neurones in vitro independent of their circadian rhythm
Autore:
Van den Top, M; Buijs, RM; Ruijter, JM; Delagrange, P; Spanswick, D; Hermes, MLHJ;
Indirizzi:
Univ Warwick, Dept Biol Sci, Neurobiol Grp, Coventry CV4 7AL, W Midlands, England Univ Warwick Coventry W Midlands England CV4 7AL 7AL, W Midlands, England Netherlands Inst Brain Res, NL-1105 AZ Amsterdam, Netherlands Netherlands Inst Brain Res Amsterdam Netherlands NL-1105 AZ Netherlands Univ Amsterdam, Acad Med Ctr, Dept Anat & Embryol, NL-1105 AZ Amsterdam, Netherlands Univ Amsterdam Amsterdam Netherlands NL-1105 AZ Z Amsterdam, Netherlands Inst Rech Int Servier, F-92415 Courbevoie, France Inst Rech Int Servier Courbevoie France F-92415 92415 Courbevoie, France
Titolo Testata:
NEUROSCIENCE
fascicolo: 1, volume: 107, anno: 2001,
pagine: 99 - 108
SICI:
0306-4522(2001)107:1<99:MGAOPC>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEMBRANE-PROPERTIES; INWARD RECTIFIER; INVITRO; RECEPTOR; CHANNEL; AUTORADIOGRAPHY; MODULATION; SLICES; CORTEX; ACCESS;
Keywords:
hyperpolarisation; open rectifier; pertussis toxin-sensitive;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Van den Top, M Univ Warwick, Dept Biol Sci, Neurobiol Grp, Gibbert Hill Campus, Coventry CV4 7AL, W Midlands, England Univ Warwick Gibbert Hill Campus Coventry W Midlands England CV4 7AL
Citazione:
M. Van den Top et al., "Melatonin generates an outward potassium current in rat suprachiasmatic nucleus neurones in vitro independent of their circadian rhythm", NEUROSCIENC, 107(1), 2001, pp. 99-108

Abstract

The present study investigated the membrane mechanisms underlying the inhibitory influence of melatonin on suprachiasmatic nucleus (SCN) neurotics ina hypothalamic slice preparation, Perforated-patch recordings were performed to prevent the rapid rundown of spontaneous firing rate as observed during whole cell recordings and to preserve circadian rhythmicity in SCN neurones. In current-clamp mode melatonin (1 muM or 1 nM) application, in the presence of agents that block action potential generation and fast synaptic transmission, resulted in a membrane hyperpolarisation accompanied with a decrease in input resistance in the majority of SCN neurotics (71-86%). The amplitude or the hyperpolarisation was not found to be significantly different between circadian time 5-12 and 14-21. In voltage-clamp mode melatonin (1 muM or 1 nM) induced an outward current accompanied with an increase in membrane conductance. The current was found to be mainly potassium driven with voltage kinetics resembling those of an open rectifying potassium conductance. Investigations into the signal transduction mechanism revealed melatonin-induced inhibition of SCN neurotics to be sensitive to pertussis toxinbut independent of intracellular cAMP levels and phospholipase C activity. The present study shows that melatonin, at night-time physiological concentrations, reduces the neuronal excitability of the majority of SCN neuronesindependent of the time of application in the circadian cycle. Thus in vivo melatonin may be important for circadian time-keeping by amplifying the circadian rhythm in SCN neurones, by lowering their sensitivity to phase-shifting stimuli occurring at night, (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/20 alle ore 16:14:13