Találati lista | Tudóstér

001-es BibID:	BIBFORM040762
Első szerző:	Batta József Tamás (fül-orr-gégész)
Cím:	Regulation of the lateral wall stiffness by acetylcholine and GABA in the outer hair cells of the guinea pig / Batta T. J., Panyi Gy., Szucs A., Sziklai I.
Dátum:	2004
ISSN:	0953-816X
Megjegyzések:	Acetylcholine (ACh) and GABA, the main neurotransmitters of the efferent innervation of the outer hair cells (OHCs), are assumed to regulate the efficacy of the cochlear amplifier through a variety of mechanisms. The recently described stretch-induced changes of the lateral wall stiffness (regulatory stiffness response) and the stretch-induced slow cell motility of OHCs may be important regulatory mechanisms in this process. We found that ACh in cochleobasal OHCs significantly reduces the stiffness of the lateral wall but increases the regulatory stiffness response and stretch-induced slow cell motility. Qualitatively similar cellular responses were evoked by GABA in cochleoapical OHCs. The effects of ACh could be inhibited by strychnine, the specific inhibitor of the alpha(9) ACh receptors expressed in OHCs, whereas the effects of GABA could be blocked by bicuculline, a specific GABA(A) receptor antagonist. In the absence of extracellular Ca(2+) the effects of ACh and GABA on the regulatory stiffness response were reduced, indicating the involvement of Ca(2+) in the control of this process. Based on our results we suggest that efferent innervation protects the organ of Corti against high sound intensities and supports adaptation by modification of the micromechanical properties of OHCs. This could be governed by ACh and GABA indirectly, via the potentiation of stretch-induced cell shortening in a Ca(2+)-dependent manner, rather than by a direct stiffness regulation-related mechanism.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	European Journal Of Neuroscience. - 20 : 12 (2004), p. 3364-3370. -
További szerzők:	Panyi György (1966-) (biofizikus) Szűcs Attila (1970-) (fül-orr-gégész) Sziklai István (1954-) (fül-orr-gégész)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM040494
Első szerző:	Dallos Péter
Cím:	Acetylcholine, outer hair cell electromotility, and the cochlear amplifier / Peter Dallos, David Z. Z. He, Xi Lin, István Sziklai, Samir Mehta, Burt N. Evans
Dátum:	1997
Megjegyzések:	The dominant efferent innervation of the cochlea terminates on outer hair cells (OHCs), with acetylcholine (ACh) being its principal neurotransmitter. OHCs respond with a somatic shape change to alterations in their membrane potential, and this electromotile response is believed to provide mechanical feedback to the basilar membrane. We examine the effects of ACh on electromotile responses in isolated OHCs and attempt to deduce the mechanism of ACh action. Axial electromotile amplitude and cell compliance increase in the presence of the ligand. This response occurs with a significantly greater latency than membrane current and potential changes attributable to ACh and is contemporaneous with Ca2+ release from intracellular stores. It is likely that increased axial compliance largely accounts for the increase in motility. The mechanical responses are probably related to a recently demonstrated slow efferent effect. The implications of the present findings related to commonly assumed efferent behavior in vivo are considered.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Journal of Neuroscience. - 17 : 6 (1997), p. 2212-2226. -
További szerzők:	He, David Z. Z. Lin, Xi Mehta, Shamir Evans, Burt N. Sziklai István (1954-) (fül-orr-gégész)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM039760
035-os BibID:	PMID:12453052
Első szerző:	Szabo Zsolt
Cím:	Ionic currents determining the membrane characteristics of type I spiral ganglion neurons of the guinea pig / Zs. Szabó, Cs. Harasztosi, I. Sziklai, G. Szűcs, Z. Rusznák
Dátum:	2002
ISSN:	0953-816X
Megjegyzések:	Enzymatically isolated type I spiral ganglion neurons of the guinea pig have been investigated in the present study. The identity of the cells was confirmed by using anti-neuron-specific enolase immunostaining. The presence and shredding of the myelin sheath was also documented by employing anti-S100 immunoreaction. The membrane characteristics of the cells were studied by using the whole-cell patch-clamp technique. The whole-cell capacitance of the cells was 9 +/- 2 pF (n = 51), while the resting membrane potential of the cells was -62 +/- 9 mV (n = 19). When suprathreshold depolarizing stimuli were applied, the neurons fired a single action potential at the beginning of the stimulation. It was confirmed in this study that type I spiral ganglion cells possess a hyperpolarization-activated nonspecific cationic current (Ih). The major characteristics of this current component were unaffected by the enzyme treatment. Type I spiral ganglion cells also expressed various depolarization-activated K+ current components. A high-threshold outward current was sensitive to 1-10 mm TEA+ application. The ganglion cells also expressed a relatively small, but nevertheless present, transient outward current component which was less sensitive to TEA+ but could be inhibited by 100 micro m 4-aminopyridine. A DTX-I-sensitive current was responsible for some 30% of the total outward current (at 0 mV), showed rapid activation at membrane potentials positive to -50 mV and demonstrated very little inactivation. However, inhibition of the highly 4-AP- or DTX-I-sensitive component did not alter the rapidly inactivating nature of the firing pattern of the cells.
Tárgyszavak:	Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	European Journal of Neuroscience. - 16 : 10 (2002), p. 1887-1895. -
További szerzők:	Harasztosi Csaba Sziklai István (1954-) (fül-orr-gégész) Szűcs Géza (1948-) (élettanász) Rusznák Zoltán (1965-) (élettanász)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: