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Titolo:
Depression of transmitter release at synapses in the rat superior cervicalganglion: the role of transmitter depletion
Autore:
Lin, YQ; Graham, K; Bennett, MR;
Indirizzi:
Univ Sydney, Dept Physiol, Neurobiol Lab, Sydney, NSW 2006, Australia UnivSydney Sydney NSW Australia 2006 ol Lab, Sydney, NSW 2006, Australia Univ Sydney, Inst Biomed Res, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 ed Res, Sydney, NSW 2006, Australia
Titolo Testata:
AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL
fascicolo: 1-2, volume: 88, anno: 2001,
pagine: 16 - 24
SICI:
1566-0702(20010412)88:1-2<16:DOTRAS>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
METABOTROPIC GLUTAMATE RECEPTORS; FROG NEUROMUSCULAR-JUNCTION; SQUID GIANT SYNAPSE; PRESYNAPTIC DEPRESSION; ACETYLCHOLINE-RELEASE; SYMPATHETIC-GANGLION; ENDOGENOUS ADENOSINE; ALPHA-ADRENOCEPTORS; TRANSMISSION; FACILITATION;
Keywords:
transmitter; depression; sympathetic; boutons;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Bennett, MR Univ Sydney, Dept Physiol, Neurobiol Lab, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 ey, NSW 2006, Australia
Citazione:
Y.Q. Lin et al., "Depression of transmitter release at synapses in the rat superior cervicalganglion: the role of transmitter depletion", AUTON NEURO, 88(1-2), 2001, pp. 16-24

Abstract

The characteristics of depression of the excitatory postsynaptic potential(EPSP) during a short train of impulses to the rat superior cervical ganglion (SCG) have been ascertained with the object of determining the relativecontributions of transmitter depletion and autoreceptors to depression. Successive EPSPs in a short train were depressed after the first (V-o) up to about the fourth impulse when a steady-state depressed EPSP level (V-ss) was reached. V-ss increased with the stimulation frequency between 1 and 30 Hz. V-o recovered after a short train with a time constant of about 2.8 s inthe frequency range from 5 to 30 Hz. In order to determine if depression was related to changes in calcium influx with successive impulses in the train, preganglionic boutons were loaded with the calcium indicator Oregon Green(TM) 488 BAPTA-1 and line scans taken through individual boutons with a confocal laser microscope. Successive calcium transients were of about the same amplitude in boutons during short trains of impulses at 5 Hz. The contribution of autoreceptors activated by the action of endogenously derived adenosine on the extent of depression of the EPSP during short trains was ascertained by blocking these receptors with 8-phenyltheophylline (10 muM). There was no change in the extent or time course of development of depression. Similar results were obtained with the opioid receptor antagonist naloxone (10 muM) and the adrenergic receptor antagonist yohimbine (10 muM). Factors, which increased the extent of transmitter release during a train, such as increasing the external calcium concentration from 0.8 to 2.5 mM, increased depression. Factors. which decreased the extent of transmitter release such as increasing the exogenous adenosine concentration between 1 and 200 muM decreased depression. These results are interpreted in terms of a modelin which vesicles are mobilised by a calcium-dependent process from a store into an available pool of docked vesicles. Depletion of the docked vesicles during exocytosis then leads to depression of transmitter release duringa train of impulses. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 11:39:01