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001-es BibID:	BIBFORM040326
035-os BibID:	PMID:14523064
Első szerző:	Melnick, Igor V.
Cím:	Ionic basis of tonic firing in spinal substantia gelatinosa neurons of rat / Igor V. Melnick, Sónia F. A. Santos, Karolina Szokol, Péter Szűcs, Boris V. Safronov
Dátum:	2004
ISSN:	0022-3077
Megjegyzések:	Ionic conductances underlying excitability in tonically firing neurons (TFNs) from substantia gelatinosa (SG) were studied by the patch-clamp method in rat spinal cord slices. Ca(2+)-dependent K(+) (K(CA)) conductance sensitive to apamin was found to prolong the interspike intervals and stabilize firing evoked by a sustained membrane depolarization. Suppression of Ca(2+) and K(CA) currents, however, did not abolish the basic pattern of tonic firing, indicating that it was generated by voltage-gated Na(+) and K(+) currents. Na(+) and K(+) channels were further analyzed in somatic nucleated patches. Na(+) channels exhibited fast activation and inactivation kinetics and followed two-exponential time course of recovery from inactivation. The major K(+) current was carried through tetraethylammonium (TEA)-sensitive rapidly activating delayed-rectifier (K(DR)) channels with a slow inactivation. The TEA-insensitive transient A-type K(+) (K(A)) current was very small in patches and was strongly inactivated at resting potential. Block of K(DR) rather than K(A) conductance by 1 mM TEA lowered the frequency and stability of firing. Intracellular staining with biocytin revealed at least three morphological groups of TFNs. Finally, on the basis of present data, we created a model of TFN and showed that Na(+) and K(DR) currents are sufficient to generate a basic pattern of tonic firing. It is concluded that the balanced contribution of all ionic conductances described here is important for generation and modulation of tonic firing in SG neurons.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Neurophysiology. - 91 : 2 (2004), p. 646-655. -
További szerzők:	Santos, Sónia F. A. Szokol Karolina Szűcs Péter (1974-) (kutatóorvos) Safronov, Boris V.
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001-es BibID:	BIBFORM029092
Első szerző:	Szűcs Péter (kutatóorvos)
Cím:	Neurons with distinctive firing patterns, morphology and distribution in laminae V-VII of the neonatal rat lumbar spinal cord / Szűcs P., Odeh F., Szokol K., Antal M.
Dátum:	2003
Megjegyzések:	It is generally accepted that neurons in the ventral spinal grey matter, a substantial proportion of which can be regarded as constituents of the spinal motor apparatus, receive and integrate synaptic inputs arising from various peripheral, spinal and supraspinal sources. Thus, a profound knowledge concerning the integrative properties of interneurons in the spinal ventral grey matter appears to be essential for a fair understanding of operational principles of spinal motor neural assemblies. Using the whole cell patch clamp configuration in a correlative physiological and morphological experimental approach, here we demonstrate that the intrinsic membrane properties of neurons vary widely in laminae V-VII of the ventral grey matter of the neonatal rat lumbar spinal cord. Based on their firing patterns in response to depolarizing current steps, we have classified the recorded neurons into four categories: 'phasic', 'repetitive', 'single' and 'slow'. Neurons with firing properties characteristic of the 'phasic', 'repetitive' and 'single' cells have previously been reported also in the superficial and deep spinal dorsal horn, but this is the first account in the literature in which 'slow' neurons have been recovered and described in the spinal cord. The physiological heterogeneity in conjunction with the morphological correlation and distribution of neurons argues that different components of motor neural assemblies in the spinal ventral grey matter possess different signal processing characteristics.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	European Journal of Neuroscience. - 17 : 3 (2003), p. 537-544. -
További szerzők:	Odeh, Francis Szokol Karolina Antal Miklós (1951-) (orvos, anatómus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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