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Titolo:
L-TYPE CALCIUM CHANNELS MEDIATE A SLOW EXCITATORY SYNAPTIC TRANSMISSION IN RAT MIDBRAIN DOPAMINERGIC-NEURONS
Autore:
BONCI A; GRILLNER P; MERCURI NB; BERNARDI G;
Indirizzi:
IST RICOVERO & CURA CARATTERE SCI SANTA LUCIA,EXPT NEUROL LAB,VIA ARDEATINA 306 I-00179 ROME ITALY IST RICOVERO & CURA CARATTERE SCI SANTA LUCIA,EXPT NEUROL LAB I-00179ROME ITALY UNIV TOR VERGATA,NEUROL CLIN I-00173 ROME ITALY
Titolo Testata:
The Journal of neuroscience
fascicolo: 17, volume: 18, anno: 1998,
pagine: 6693 - 6703
SICI:
0270-6474(1998)18:17<6693:LCCMAS>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
VENTRAL TEGMENTAL AREA; METABOTROPIC GLUTAMATE RECEPTORS; SUBSTANTIA-NIGRA; CA2+ CHANNELS; N-TYPE; SUBTHALAMIC NUCLEUS; GUINEA-PIG; TRANSMITTER RELEASE; IN-VITRO; P-TYPE;
Keywords:
DOPAMINE NEURONS; L-TYPE CALCIUM CHANNELS; DIHYDROPYRIDINES; EXCITATORY POSTSYNAPTIC CURRENTS; MIDBRAIN; ELECTROPHYSIOLOGY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
64
Recensione:
Indirizzi per estratti:
Citazione:
A. Bonci et al., "L-TYPE CALCIUM CHANNELS MEDIATE A SLOW EXCITATORY SYNAPTIC TRANSMISSION IN RAT MIDBRAIN DOPAMINERGIC-NEURONS", The Journal of neuroscience, 18(17), 1998, pp. 6693-6703

Abstract

Patch pipettes were used to record whole-cell synaptic currents undervoltage-clamp in dopaminergic neurons in slices of rat substantia nigra pars compacta and ventral tegmental area. We report that dihydropyridines (DHPs), L-type Ca2+ channel antagonists, depressed a slow EPSC (EPSCslow) evoked by a train of focally delivered electrical stimuli. In fact, the amplitude of the EPSCslow was reduced by the DHP antagonists nifedipine (1-100 mu M), nimodipine (1-100 mu M), and isradipine (30 nM-100 mu M) in a concentration-dependent and reversible manner. Onthe other hand, Bay-K 8644 (1 mu M), an L-type Ca2+ channel agonist, increased the EPSCslow. The DHPs depressed the EPSCslow only when the high-frequency stimulation that was used to evoke this synaptic current lasted >70 msec. On the other hand, Bay-K 8644 increased the amplitude of the EPSCslow only when it was evoked by a train <70 msec. Moreover, the DHPs did not affect the EPSCfast, the IPSC and the IPSCslow. The inhibition of the EPSCslow caused by the DHPs is attributed to presynaptic mechanisms because (1) the inward current generated by exogenously administered glutamate was not affected and (2) the EPSCslow was reduced to a similar degree even when the activation state of postsynaptic L-type Ca2+ channels was changed by holding the neurons at -100, -60, and +30 mV. Finally, a DHP-sensitive component of the EPSCslow could even be detected after the blockade of N-, Q-, and P-type Ca2+ channels by the combination of omega-conotoxin GVIA, omega-agatoxin IVA, and omega-conotoxin MVIIC. Taken together, these results indicate thatunder certain pat terns of synaptic activity, L-type Ca2+ channels regulate the synaptic release of excitatory amino acids on the dopaminergic neurons of the ventral mesencephalon.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 19:20:15