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Titolo:
CHOLINERGIC AND ELECTRICAL SYNAPSES BETWEEN SYNERGISTIC SPINAL MOTONEURONS IN THE XENOPUS-LAEVIS EMBRYO
Autore:
PERRINS R; ROBERTS A;
Indirizzi:
UNIV BRISTOL,SCH BIOL SCI,WOODLAND RD BRISTOL BS8 1UG AVON ENGLAND UNIV BRISTOL,SCH BIOL SCI BRISTOL BS8 1UG AVON ENGLAND
Titolo Testata:
Journal of physiology
fascicolo: 1, volume: 485, anno: 1995,
pagine: 135 - 144
SICI:
0022-3751(1995)485:1<135:CAESBS>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
RECURRENT AXON COLLATERALS; RENSHAW CELLS; SYNAPTIC POTENTIALS; ALPHA-MOTONEURONS; NEURONS; CORD; CAT; MECHANISMS; COORDINATION; LOCOMOTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
R. Perrins e A. Roberts, "CHOLINERGIC AND ELECTRICAL SYNAPSES BETWEEN SYNERGISTIC SPINAL MOTONEURONS IN THE XENOPUS-LAEVIS EMBRYO", Journal of physiology, 485(1), 1995, pp. 135-144

Abstract

1. To investigate central motoneurone synapses within the spinal cordof a simple vertebrate, the Xenopus embryo, simultaneous intracellular recordings were made from fifty-five pairs of spinal motoneurones. 2. Chemical synapses were found between seventeen out of thirty-five pairs on the same side of the spinal cord. Current-evoked spikes in the presynaptic neurone led to fast depolarizing postsynaptic potentials (PSPs) in the postsynaptic neurone at latencies of 0.5-1.5 ms. The PSPshad an average amplitude of 7 mV, a rise time of 8 ms and a half-falltime of 18 ms. 3. The presynaptic motoneurone was always the more rostral of the pair. No excitatory connections were found which crossed the cord. The fast PSPs were blocked by 10 mu M mecamylamine but not by1 mM kynurenic acid, so were mediated by nicotinic acetylcholine receptors (nAChRs). These are the first unitary excitatory postsynaptic potentials (EPSPs) mediated by nAChRs recorded intracellularly within the vertebrate central nervous system. 4. Bidirectional electrical synapses were found between five pairs of motoneurones. All these pairs were on the same side of the spinal cord and less than 70 mu m apart. Each neurone responded in a graded manner to either hyperpolarizing or depolarizing current injected into the other. 5. Since motoneurones are rhythmically active during swimming, both chemical and electrical synapses will add to the fast on-cycle excitation underlying spiking activity in other motoneurones. This may increase the reliability and localsynchrony of synergistic motoneurone firing during locomotion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 21:51:01