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Titolo:
SYNAPTIC TRANSMISSION AT SINGLE VISUALIZED HIPPOCAMPAL BOUTONS
Autore:
LIU G; TSIEN RW;
Indirizzi:
STANFORD UNIV,MED CTR,DEPT MOLEC & CELLULAR PHYSIOL STANFORD CA 94305 STANFORD UNIV,MED CTR,DEPT MOLEC & CELLULAR PHYSIOL STANFORD CA 94305
Titolo Testata:
Neuropharmacology
fascicolo: 11, volume: 34, anno: 1995,
pagine: 1407 - 1421
SICI:
0028-3908(1995)34:11<1407:STASVH>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
LONG-TERM POTENTIATION; SECRETION; MINIATURE; CURRENTS; NEURONS; SYNAPSES; RELEASE; MODEL; CELLS;
Keywords:
HIPPOCAMPAL SYNAPSES; BOUTONS; NEUROTRANSMISSION; EXCITATORY POSTSYNAPTIC CURRENTS (EPSCS); INHIBITORY POSTSYNAPTIC CURRENTS (IPSCS);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
G. Liu e R.W. Tsien, "SYNAPTIC TRANSMISSION AT SINGLE VISUALIZED HIPPOCAMPAL BOUTONS", Neuropharmacology, 34(11), 1995, pp. 1407-1421

Abstract

We have used a focal stimulation method to study neurotransmission atsynapses onto hippocampal pyramidal neurons in cultures derived from neonatal rats. Single functional boutons were visualized by activity-dependent preloading with the fluorescent dye FM1-43, then focally stimulated by localized application of elevated K+/Ca2+ solution via a puffer pipette, while postsynaptic currents were recorded under whole cell voltage clamp (Liu and Tsien, 1995). This paper gives a detailed description of the main properties of this experimental system and of information it has provided about fundamental properties of hippocampal synapses. Most of the experiments focused on excitatory postsynaptic currents (EPSCs), but preliminary recordings of inhibitory events (IPSCs) are also reported here. The unitary EPSCs at individual synapses varied greatly in amplitude, but were relatively uniform in their time course. The frequency of the synaptic events was greatly reduced by lowering the external Ca2+ concentration or by application of baclofen, a GABA(B) receptor agonist. Frequent repetitive stimulation produced a decline in the incidence of EPSCs that was readily reversed upon rest. We attribute the decline to exhaustion of a pool of available vesicles; typically, recovery proceeded with a time constant of similar to 40 sec (23 degrees C), and involved a vesicular pool capable of generating similar to 90 EPSCs without recycling. While synaptic currents were broadly distributed in amplitude (Bekkers et al., 1990), this distribution was remarkably similar at multiple synapses on a given postsynaptic neuron. The median synaptic current amplitude varied 4-fold across different cells, decreasing markedly with increasingly dense synaptic innervation. The implications of these results for cellular signal processing and quantal analysis are discussed.

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Documento generato il 12/07/20 alle ore 06:31:31