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Titolo:
INDEPENDENT DEPRESSIVE MECHANISMS OF GABA AND (+ -)-8-HYDROXY-DIPROPYLAMINOTETRALIN HYDROBROMIDE ON YOUNG-RAT SPINAL AXONS/
Autore:
SAKUMA J; CIPOREN J; ABRAHAMS J; YOUNG W;
Indirizzi:
NYU,MED CTR,DEPT NEUROSURG,550 1ST AVE NEW YORK NY 10016 NYU,MED CTR,DEPT NEUROSURG NEW YORK NY 10016
Titolo Testata:
Neuroscience
fascicolo: 3, volume: 75, anno: 1996,
pagine: 927 - 938
SICI:
0306-4522(1996)75:3<927:IDMOGA>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXCITATORY AMINO-ACIDS; DORSAL RAPHE NEURONS; HIPPOCAMPAL PYRAMIDAL CELLS; OPTIC-NERVE; MOLECULAR-CLONING; PERIPHERAL-NERVE; EXTRACELLULAR K+; ENDOGENOUS GABA; IMPACT INJURY; CORD ISCHEMIA;
Keywords:
(+/-)-8-HYDROXY-DIPROPYLAMINOTETRALIN HYDROBROMIDE (8-OH-DPAT); GABA; CONDUCTION VELOCITIES; OUABAIN; EXTRACELLULAR POTASSIUM [(K+)(E)];
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
69
Recensione:
Indirizzi per estratti:
Citazione:
J. Sakuma et al., "INDEPENDENT DEPRESSIVE MECHANISMS OF GABA AND (+ -)-8-HYDROXY-DIPROPYLAMINOTETRALIN HYDROBROMIDE ON YOUNG-RAT SPINAL AXONS/", Neuroscience, 75(3), 1996, pp. 927-938

Abstract

We compared the effect of GABA and the serotonin receptor agonist (+/-)-8-hydroxy-dipropylaminotetralin hydrobromide (8-OH-DPAT) on compound action potential amplitudes, latency, and conduction velocity in thespinal cord isolated from young (eight to 13-day-old) Long-Evans hooded rats. Supramaximally activated conducting action potentials and extracellular K+ activity were recorded with microelectrodes from the cuneatus-gracilis fasciculi and corticospinal tract. In the cuneatus-gracilis fasciculi, 8-OH-DPAT (10(-4) M) significantly reduced response amplitudes by 26.1+/-10.3% (mean+/-S.D., P <0.0001, paired t-test, n=27)and increased latencies by 20.3+/-7.9% (P <0.0001). GABA (10(-4) M) reduced amplitudes by 31.7+/-15.0% (P <0.0001, n=28) and increased latencies by 6.1+/-5.4% (P <0.0001). However, neither GABA nor 8-OH-DPAT significantly altered conduction velocities, suggesting that the latency shifts are due to changes in activation time and not conduction velocity. In cortical spinal tract, 8-OH-DPAT (10(-4) M) depressed response amplitudes by 18.9+/-9.6% (P <0.05, n=5), increased latencies by 23.3+/-7.2% (P <0.0001), but reduced conduction velocities by 19.9+/-10.2%. GABA (10(-4) M) reduced amplitudes by 16.4+/-7.5% (P <0.01, n=5), increased latencies by 5.3+/-2.3% (P <0.05), and did not change conduction velocities. Bicuculline or picrotoxin blocked the GABA effects butdid not affect the 8-OH-DPAT effects on both tracts. The potassium channel blocker tetraethylammonium did not alter the 8-OH-DPAT effects. The Na+/K+-ATPase inhibitor ouabain (10(-6) M) markedly enhanced the depressive GABA effects from 27.9+/-12.0% to 49.4+/-24.5% (P <0.01, n=9), but had no effect on 8-OH-DPAT-mediated effects. These results suggest that GABA and serotonin agonists depress axonal excitability through different and independent mechanisms. Copyright (C) 1996 IBRO.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 21:47:50