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Titolo:
TACHYKININS MAY MODIFY SPONTANEOUS EPILEPTIFORM ACTIVITY IN THE RAT ENTORHINAL CORTEX IN-VITRO BY ACTIVATING GABAERGIC INHIBITION
Autore:
MAUBACH KA; CODY C; JONES RSG;
Indirizzi:
UNIV BRISTOL,SCH MED SCI,DEPT PHYSIOL,UNIV WALK BRISTOL BS8 1TD AVON ENGLAND UNIV BRISTOL,SCH MED SCI,DEPT PHYSIOL BRISTOL BS8 1TD AVON ENGLAND
Titolo Testata:
Neuroscience
fascicolo: 4, volume: 83, anno: 1998,
pagine: 1047 - 1062
SICI:
0306-4522(1998)83:4<1047:TMMSEA>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL-NERVOUS-SYSTEM; ACID-INDUCED SEIZURES; P-IMMUNOREACTIVE NEURONS; APPLIED SUBSTANCE-P; PYRAMIDAL NEURONS; NEUROKININ-B; HIPPOCAMPAL-FORMATION; DIFFERENTIAL CHANGES; CORTICAL-NEURONS; CINGULATE CORTEX;
Keywords:
SUBSTANCE P; TACHYKININS; ENTORHINAL CORTEX; EPILEPTIFORM ACTIVITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
52
Recensione:
Indirizzi per estratti:
Citazione:
K.A. Maubach et al., "TACHYKININS MAY MODIFY SPONTANEOUS EPILEPTIFORM ACTIVITY IN THE RAT ENTORHINAL CORTEX IN-VITRO BY ACTIVATING GABAERGIC INHIBITION", Neuroscience, 83(4), 1998, pp. 1047-1062

Abstract

The effects of substance P and related tachykinins on intrinsic membrane properties and synaptic responses of neurons in cortical slices were determined. Substance P had no detectable effect on membrane properties of principal neurons in layer II or V of the rat medial entorhinal cortex or on neurons in either layer of the anterior cingulate cortex. Specific agonists at the neurokinin(1)-receptor were also without effect as were agonists at both neurokinin(2)- and neurokinin(3)-receptors. Substance P hyperpolarized a small number of principal neurons. These responses were weak and desensitized with repeated applications. Similar effects were seen with other neurokinin(1)-receptor agonists. Excitatory synaptic potentials mediated by either alpha-amino-3-hydroxy-5-methyl-4-isoxazolepionate- or N-methyl-D-aspartate-receptors in principal neurons of the entorhinal cortex were unaffected by substance P. Responses of entorhinal neurons to iontophoretically applied glutamate and N-methyl-D-aspartate were also unaffected. Inhibitory synapticpotentials mediated by either GABA(A)- or GABA(B)-receptors in entorhinal neurons were slightly but consistently enhanced by substance P. Neurons identified as interneurons on the basis of their firing characteristics were consistently depolarized by substance P. These responsesalso desensitized with repeated applications. Spontaneous epileptiform discharges evoked in entorhinal cortex by perfusion with a GABA(A)-receptor antagonist (bicuculline), were reduced in frequency and, sometimes, in duration by substance P. This effect was mimicked by other neurokinin, receptor agonists and blocked by neurokinin(1)-receptor antagonists. It was also mimicked by neurokinin A but not by a specific neurokinin(2)-receptor agonist. The reduction in frequency of dischargeswas also mimicked by a GABA(B)-receptor agonist, L-baclofen, and blocked by the GABA(B)-receptor antagonist, CGP55845A, Neurokinin B, and aspecific neurokinin(3)-receptor agonist (senktide), increased the frequency and (sometimes) duration of epileptiform discharges. Substance P could also increase frequency but this usually succeeded or precededa decrease in frequency. The effect of neurokinin B was reduced by a metabotropic glutamate receptor antagonist. Substance P appears to have little direct effect on principal neurons of the entorhinal cortex but may hyperpolarize them indirectly by activating interneurons and releasing GABA. This indirect inhibition may be responsible for the ability of substance P to reduce the frequency of epileptiform discharges in the entorhinal cortex and may suggest that neurokinin(1)-receptor agonists have potential as anticonvulsant drugs. (C) 1998 IBRO. Published by Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 13:24:15