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Titolo:
Opioid modulation of recurrent excitation in the hippocampal dentate gyrus
Autore:
Terman, GW; Drake, CT; Simmons, ML; Milner, TA; Chavkin, C;
Indirizzi:
Univ Washington, Sch Med, Dept Anesthesiol, Seattle, WA 98195 USA Univ Washington Seattle WA USA 98195 t Anesthesiol, Seattle, WA 98195 USA Univ Washington, Sch Med, Dept Pharmacol, Seattle, WA 98195 USA Univ Washington Seattle WA USA 98195 ept Pharmacol, Seattle, WA 98195 USA Univ Washington, Sch Med, Grad Program Neurobiol & Behav, Seattle, WA 98195 USA Univ Washington Seattle WA USA 98195 obiol & Behav, Seattle, WA 98195 USA Cornell Univ, Dept Neurol & Neurosci, Weill Med Coll, New York, NY 10021 USA Cornell Univ New York NY USA 10021 Weill Med Coll, New York, NY 10021 USA
Titolo Testata:
JOURNAL OF NEUROSCIENCE
fascicolo: 12, volume: 20, anno: 2000,
pagine: 4379 - 4388
SICI:
0270-6474(20000615)20:12<4379:OMOREI>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
LONG-TERM POTENTIATION; TEMPORAL-LOBE EPILEPSY; GUINEA-PIG HIPPOCAMPUS; KAINATE-TREATED RATS; MOSSY FIBER SYNAPSES; GRANULE CELLS; ULTRASTRUCTURAL-LOCALIZATION; DYNORPHIN IMMUNOREACTIVITY; SYNAPTIC REORGANIZATION; ENDOGENOUS DYNORPHINS;
Keywords:
hippocampus; dentate gyrus; kappa opioids; endogenous opioids; dynorphin; long-term potentiation; mossy fibers; hilus; granule cell; guinea pig;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Terman, GW Univ Washington, Sch Med, Dept Anesthesiol, Box 356540, Seattle, WA 98195 USA Univ Washington Box 356540 Seattle WA USA 98195 e, WA 98195 USA
Citazione:
G.W. Terman et al., "Opioid modulation of recurrent excitation in the hippocampal dentate gyrus", J NEUROSC, 20(12), 2000, pp. 4379-4388

Abstract

kappa opioid receptor activation inhibits granule cell-mediated excitatoryneurotransmission in the hippocampal formation via a decrease in glutamaterelease from both perforant path and mossy fiber terminals. We now report a third, anatomically and pharmacologically distinct site of such kappa opioid inhibition within the hippocampus. Granule cell population responses toselective stimulation of an excitatory hilar pathway were decreased by thekappa(1) opioid receptor agonist U69,593, an effect blocked by the kappa(1) antagonist norbinaltorphimine. U69,593 also inhibited hilar path induced long-term potentiation (LTP) of granule cell responses. LTP in this pathwaywas also blocked by the NMDA receptor antagonist D-2-amino-5-phosphonovalerate, unlike granule cell mossy fiber LTP in CA3. The kappa opioid peptide dynorphin is present in hilar mossy fiber collaterals. Ultrastructural analysis of these collaterals demonstrated dynorphin-containing vesicles in asymmetric synapses formed between axon terminals and granule cell dendrites, suggesting direct granule cell-granule cell connections. Evoked release of endogenous dynorphin within the hilus was effective in reducing hilar excitation of granule cells, although this release, incontrast to the release of dynorphin in the dentate molecular layer, was not dependent on L-type calcium channels. No hilar path excitation was observed in the absence of bicuculline, suggesting a strong GABA(A)-mediated inhibition of this pathway. However, hilar path activity could be seen after LTP, with or without bicuculline. Thus, kopioids can inhibit granule cell recurrent excitation, likely via effects on excitatory mossy fiber collaterals. Such collaterals are thought to be important in mediating temporal lobe epilepsy.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 12:14:44