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001-es BibID:	BIBFORM060205
Első szerző:	Luz, Liliana L.
Cím:	Peripherally driven low-threshold inhibitory inputs to lamina I local-circuit and projection neurones : a new circuit for gating pain responses / Liliana L. Luz, Peter Szucs, Boris V. Safronov
Dátum:	2014
ISSN:	0022-3751
Megjegyzések:	Spinal lamina I is a key element of the pain processing system which relays primary afferent input to supraspinal areas. However, little is known about how the signal is modulated by its intrinsic network including local-circuit neurones (LCNs) and much less numerous anterolateral tract projection neurones (PNs). Here, we used whole-cell patch clamp recordings in an isolated spinal cord preparation to examine properties of identified LCNs (n = 85) and PNs (n = 73) in their functionally preserved local networks. Forty LCNs showed spontaneous rhythmic firing (2-7 Hz) at zero current injection, which persisted in the presence of blockers of fast synaptic transmission. In the remaining cases, most LCNs and PNs fired tonically in response to depolarizing current injections. We identified LCNs and PNs receiving low-threshold primary afferent-driven inhibitory inputs, which in many cases were disynaptic and temporally preceded classical high-threshold excitatory inputs. This direct inhibitory link between low-threshold afferents and PNs can function as a postsynaptic gate controlling the nociceptive information flow in the spinal cord. The LCNs were found to be integrated into the superficial dorsal horn network by their receipt of monosynaptic and disynaptic inputs from other lamina I and II neurones. One-third of LCNs and two-thirds of PNs tested responded to substance P application. Thus, substance P released by a noxious afferent stimulation may excite PNs in two ways: directly, and via the activation of presynaptic LCN circuitries. In conclusion, we have described important properties of identified lamina I neurones and their roles in a new circuit for gating pain responses.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban ACSF artificial cerebrospinal fluid CV, conduction velocity LCNs, local-circuit neurones NK1Rs, neurokinin 1 receptors PNs, projection neurones RMP, resting membrane potential
Megjelenés:	Journal Of Physiology-London. - 592 : 7 (2014), p. 1519-1534. -
További szerzők:	Szűcs Péter (1974-) (kutatóorvos) Safronov, Boris V.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM040313
035-os BibID:	PMID:20876196
Első szerző:	Luz, Liliana L.
Cím:	Monosynaptic excitatory inputs to spinal lamina I anterolateral-tract-projecting neurons from neighbouring lamina I neurons / Liliana L. Luz, Peter Szucs, Raquel Pinho, Boris V. Safronov
Dátum:	2010
ISSN:	0022-3751
Megjegyzések:	Spinal lamina I receives nociceptive primary afferent input to project through diverse ascending pathways, including the anterolateral tract (ALT). Large projection neurons (PNs) form only a few per cent of the cell population in this layer, and little is known about their local input from other lamina I neurons. We combined single-cell imaging in the isolated spinal cord, paired recordings, 3-D reconstructions of biocytin-labelled neurons and computer simulations to study the monosynaptic input to large ALT-PNs from neighbouring (somata separated by less than 80 m) large lamina I neurons. All 11 connections identified were excitatory. We have found that an axon of a presynaptic neuron forms multiple synapses on an ALT-PN, and both Ca(2+)-permeable and Ca(2+)-impermeable AMPA receptors are involved in transmission. The monosynaptic EPSC latencies (1-12 ms) are determined by both post- and presynaptic factors. The postsynaptic delay, resulting from the electrotonic EPSC propagation in the dendrites of an ALT-PN, could be 4 ms at most. The presynaptic delay, caused by the spike propagation in a narrow highly branched axon of a local-circuit neuron, can be about 10 ms for neighbouring ALT-PNs and longer for more distant neurons. In many cases, the EPSPs evoked by release from a lamina I neuron were sufficient to elicit a spike in an ALT-PN. Our data show that ALT-PNs can receive input from both lamina I local-circuit neurons and other ALT-PNs. We suggest that lamina I is a functionally interconnected layer. The intralaminar network described here can amplify the overall output from the principal spinal nociceptive projection area.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Physiology. - 588 : 22 (2010), p. 4489-4505. -
További szerzők:	Szűcs Péter (1974-) (kutatóorvos) Pinho, Raquel Safronov, Boris V.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM040330
Első szerző:	Maccaferri, Gianmaria
Cím:	Cell surface domain specific postsynaptic currents evoked by identified GABAergic neurones in rat hippocampus in vitro / Gianmaria Maccaferri, J. David B. Roberts, Peter Szucs, Carol A. Cottingham, Peter Somogyi
Dátum:	2000
Megjegyzések:	1. Inhibitory postsynaptic currents (IPSCs) evoked in CA1 pyramidal cells (n = 46) by identified interneurones (n = 43) located in str. oriens were recorded in order to compare their functional properties and to determine the effect of synapse location on the apparent IPSC kinetics as recorded using somatic voltage clamp at -70 mV and nearly symmetrical [Cl-]. 2. Five types of visualised presynaptic interneurone, oriens-lacunosum moleculare (O-LMC), basket (BC), axo-axonic (AAC), bistratified (BiC) and oriens-bistratified (O-BiC) cells, were distinguished by immunocytochemistry and/or synapse location using light and electron microscopy. 3. Somatostatin immunoreactive O-LMCs, innervating the most distal dendritic shafts and spines, evoked the smallest amplitude (26 +/- 10 pA, s.e.m., n = 8) and slowest IPSCs (10-90 % rise time, 6.2 +/- 0.6 ms; decay, 20.8 +/- 1.7 ms, n = 8), with no paired-pulse modulation of the second IPSC (93 +/- 4 %) at 100 ms interspike interval. In contrast, parvalbumin-positive AACs evoked larger amplitude (308 +/- 103 pA, n = 7) and kinetically faster (rise time, 0.8 +/- 0.1 ms; decay 11.2 +/- 0.9 ms, n = 7) IPSCs showing paired-pulse depression (to 68 +/- 5 %, n = 6). Parvalbumin- or CCK-positive BCs (n = 9) terminating on soma/dendrites, BiCs (n = 4) and O-BiCs (n = 7) innervating dendrites evoked IPSCs with intermediate kinetic parameters. The properties of IPSCs and sensitivity to bicuculline indicated that they were mediated by GABAA receptors. 4. In three cases, kinetically complex, multiphasic IPSCs, evoked by an action potential in the recorded basket cells, suggested that coupled interneurones, possibly through electrotonic junctions, converged on the same postsynaptic neurone. 5. The population of O-BiCs (4 of 4 somatostatin positive) characterised in this study had horizontal dendrites restricted to str. oriens/alveus and innervated stratum radiatum and oriens. Other BiCs had radial dendrites as described earlier. The parameters of IPSCs evoked by BiCs and O-BiCs showed the largest cell to cell variation, and a single interneurone could evoke both small and slow as well as large and relatively fast IPSCs. 6. The kinetic properties of the somatically recorded postsynaptic current are correlated with the innervated cell surface domain. A significant correlation of rise and decay times for the overall population of unitary IPSCs suggests that electrotonic filtering of distal responses is a major factor for the location and cell type specific differences of unitary IPSCs, but molecular heterogeneity of postsynaptic GABAA receptors may also contribute to the observed kinetic differences. Furthermore, domain specific differences in the short-term plasticity of the postsynaptic response indicate a differentiation of interneurones in activity-dependent responses.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Physiology. - 524 : 1 (2000), p. 91-116. -
További szerzők:	Roberts, J. David B. Szűcs Péter (1974-) (kutatóorvos) Cottingham, Carol A. Somogyi Péter
Internet cím:	Szerző által megadott URL Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM004505
Első szerző:	Pinto, Vitor
Cím:	Monosynaptic convergence of C- and A(delta)-afferent fibres from different segmental dorsal roots on to single substantia gelatinosa neurones in the rat spinal cord / Vitor Pinto, Peter Szűcs, Victor A. Derkach, Boris V. Safronov
Dátum:	2008
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	The Journal of Physiology (London). - 586 : 17 (2008), p. 4165-4177. -
További szerzők:	Szűcs Péter (1974-) (kutatóorvos) Derkach, Victor A. Safronov, Boris V.
Internet cím:	elektronikus változat DOI
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