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Titolo:
REPETITIVE FIRING AND OSCILLATORY ACTIVITY OF PYRAMIDAL-LIKE BURSTINGNEURONS IN THE RAT SUBICULUM
Autore:
MATTIA D; KAWASAKI H; AVOLI M;
Indirizzi:
3801 UNIV MONTREAL PQ H3A 2B4 CANADA MCGILL UNIV,MONTREAL NEUROL INST MONTREAL PQ CANADA MCGILL UNIV,DEPT NEUROL & NEUROSURG MONTREAL PQ CANADA MCGILL UNIV,DEPT PHYSIOL MONTREAL PQ CANADA
Titolo Testata:
Experimental Brain Research
fascicolo: 3, volume: 114, anno: 1997,
pagine: 507 - 517
SICI:
0014-4819(1997)114:3<507:RFAOAO>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEMBRANE-POTENTIAL OSCILLATIONS; CORTEX LAYER-II; LONG-TERM POTENTIATION; HIPPOCAMPAL-NEURONS; IN-VITRO; DIFFERENTIAL ELECTRORESPONSIVENESS; ELECTROPHYSIOLOGICAL PROPERTIES; INTRINSIC-PROPERTIES; NEOCORTICAL NEURONS; SYNAPTIC RESPONSES;
Keywords:
FIRING MODES; AFTERHYPERPOLARIZATIONS; MEMBRANE OSCILLATIONS; SUBICULUM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
D. Mattia et al., "REPETITIVE FIRING AND OSCILLATORY ACTIVITY OF PYRAMIDAL-LIKE BURSTINGNEURONS IN THE RAT SUBICULUM", Experimental Brain Research, 114(3), 1997, pp. 507-517

Abstract

Electrophysiological characterization of neurons within the rat subiculum was carried out with intracellular recordings in an in vitro slice preparation. Subicular neurons responded to threshold pulses of depolarizing current delivered at a resting membrane potential (RMP) of -65.7+/-5.8 mV (mean+/-SD, n=85) with an initial burst of three to five fast action potentials that rode on a depolarizing envelope and was terminated by an afterhyperpolarization (burst AHP) (duration 113+/-35 ms; peak amplitude 2.7+/-0.6 mV, n=10). Tonic firing replaced the bursting mode at membrane potential less negative than -55 mV. Suprathreshold depolarizing pulses evoked at RMP both an initial burst and successive tonic firing. Intracellular staining with biocytin showed morphological features typical of pyramidal cells (n=8). The relationship between frequency of repetitive firing and injected current (f-I) revealedthat the burst firing frequency (250-300 Hz) was only slightly influenced by the amount of injected current. By contrast, the f-I curve of the tonic firing phase depended upon current intensity: it displayed an initial segment that increased at first linearly and then turned into a plateau for both the early and the late inter-spike intervals. Thefrequency of the tonic firing declined only slightly with time, thus suggesting a lack of adaptation. During tonic firing, each single action potential was followed by a fast AHP and a depolarizing afterpotential. Termination of repetitive firing was followed by an AHP (spike-train AHP; duration 223+/-101 ms, peak amplitude 5.6+/-2.4 mV, n=17). Fast spike-train and burst AHPs were reduced by bath application of the Ca2+-channel blockers Co2+ (2 mM) and Cd2+ (1 mM) (n=8), thus suggesting the participation of Ca2+ dependent K+ conductances in these AHPs. Subicular bursting neurons generated persistent, subthreshold voltage oscillations at 5.3+/-1 Hz (n=20) during steady depolarization positive to -60 mV; at values positive to -55 mV, the oscillatory activity could trigger clusters of single action potentials with a periodicity of0.9-2 Hz. Oscillations were not prevented by application of excitatory amino acid receptor and GABAA receptor antagonists (n=5), Ca2+-channel blockers (n=5), or Cs+ (3 mM; n=4), but were abolished by the Na+-channel blocker tetrodotoxin (1 mu M; n=6). Our findings demonstrate that pyramidal-like subicular neurons generate both bursting and non-adapting tonic firing, depending upon their membrane potential. These neurons also display oscillatory activity in the range of theta frequencythat depends on the activation of a voltage-gated Na+ conductance. These electrophysiological proper ties may play a role in the process ofsignals arising from the hippocampal formation before being funnelledtowards other limbic structures.

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Documento generato il 26/01/20 alle ore 10:12:48