JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 84: 139-151, 2000;
0022-3077/00 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (32)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chen, J. W. Y.
Right arrow Articles by Eatock, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chen, J. W. Y.
Right arrow Articles by Eatock, R. A.

The Journal of Neurophysiology Vol. 84 No. 1 July 2000, pp. 139-151
Copyright ©2000 by the American Physiological Society

Major Potassium Conductance in Type I Hair Cells From Rat Semicircular Canals: Characterization and Modulation by Nitric Oxide

James W. Y. Chen1,2 and Ruth Anne Eatock2

 1Neuroscience Program, University of Rochester, Rochester, New York 14642; and  2The Bobby R. Alford Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, Texas 77030

Chen, James W. Y. and Ruth Anne Eatock. Major Potassium Conductance in Type I Hair Cells From Rat Semicircular Canals: Characterization and Modulation by Nitric Oxide. J. Neurophysiol. 84: 139-151, 2000. Mammalian vestibular organs have two types of hair cell, type I and type II, which differ morphologically and electrophysiologically. Type I hair cells alone express an outwardly rectifying current, IK,L, which activates at relatively negative voltages. We used whole cell and patch configurations to study IK,L in hair cells isolated from the sensory epithelia of rat semicircular canals. IK,L was potassium selective, blocked by 4-aminopyridine, and permeable to internal cesium. It activated with sigmoidal kinetics and was half-maximally activated at -74.5 ± 1.6 mV (n = 35; range -91 to -50 mV). It was a very large conductance (91 ± 8 nS at -37 mV; 35 nS/pF for a cell of average size). Patch recordings from type I cells revealed a candidate ion channel with a conductance of 20-30 pS. Because IK,L was activated at the resting potential, the cells had low input resistances (Rm): median 25 MOmega at -67 mV versus 1.3 GOmega for type II cells. Consequently, injected currents comparable to large transduction currents (300 pA) evoked small (<= 10 mV) voltage responses. The cells' small voltage responses and negative resting potentials (VR = -81.3 ± 0.2 mV, n = 144) pose a problem for afferent neurotransmission: how does the receptor potential depolarize the cell into the activation range of Ca2+ channels (positive to -60 mV) that mediate transmitter release? One possibility, suggested by spontaneous positive shifts in the activation range of IK,L during whole cell recording, is that the activation range might be modulated in vivo. Any factor that reduces the number of IK,L channels open at VR will increase Rm and depolarize VR. Nitric oxide (NO) is an ion channel modulator that is present in vestibular epithelia. Four different NO donors, applied externally, inhibited the IK,L conductance at -67 mV, with mean effects ranging from 33 to 76%. The NO donor sodium nitroprusside inhibited channel activity in patches when they were cell-attached but not excised, suggesting an intracellular cascade. Consistent with an NO-cGMP cascade, 8-bromo-cGMP also inhibited whole cell IK,L. Ca2+-dependent NO synthase is reported to be in hair cells and nerve terminals in the vestibular epithelium. Excitatory input to vestibular organs may lead, through Ca2+ influx, to NO production and inhibition of IK,L. The resulting increase in Rm would augment the receptor potential, a form of positive feedback.




This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
J. C. Holt, S. Chatlani, A. Lysakowski, and J. M. Goldberg
Quantal and Nonquantal Transmission in Calyx-Bearing Fibers of the Turtle Posterior Crista
J Neurophysiol, September 1, 2007; 98(3): 1083 - 1101.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
J. R. Holt, E. A. Stauffer, D. Abraham, and G. S. G. Geleoc
Dominant-Negative Inhibition of M-Like Potassium Conductances in Hair Cells of the Mouse Inner Ear
J. Neurosci., August 15, 2007; 27(33): 8940 - 8951.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
A. Brugeaud, C. Travo, D. Dememes, M. Lenoir, J. Llorens, J.-L. Puel, and C. Chabbert
Control of Hair Cell Excitability by Vestibular Primary Sensory Neurons
J. Neurosci., March 28, 2007; 27(13): 3503 - 3511.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
A. Almanza, F. Navarrete, R. Vega, and E. Soto
Modulation of Voltage-Gated Ca2+ Current in Vestibular Hair Cells by Nitric Oxide
J Neurophysiol, February 1, 2007; 97(2): 1188 - 1195.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
K. M. Hurley, S. Gaboyard, M. Zhong, S. D. Price, J. R. A. Wooltorton, A. Lysakowski, and R. A. Eatock
M-Like K+ Currents in Type I Hair Cells and Calyx Afferent Endings of the Developing Rat Utricle
J. Neurosci., October 4, 2006; 26(40): 10253 - 10269.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
F. Mercado, I. A. Lopez, D. Acuna, R. Vega, and E. Soto
Acid-Sensing Ionic Channels in the Rat Vestibular Endorgans and Ganglia
J Neurophysiol, September 1, 2006; 96(3): 1615 - 1624.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
V. Zampini, P. Valli, G. Zucca, and S. Masetto
Single-Channel L-Type Ca2+ Currents in Chicken Embryo Semicircular Canal Type I and Type II Hair Cells
J Neurophysiol, August 1, 2006; 96(2): 602 - 612.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
N.-L. R. Han, J.-S. Ye, A. C. H. Yu, and F.-S. Sheu
Differential Mechanisms Underlying the Modulation of Delayed-Rectifier K+ Channel in Mouse Neocortical Neurons by Nitric Oxide
J Neurophysiol, April 1, 2006; 95(4): 2167 - 2178.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
K. J. Rennie and M. A. Streeter
Voltage-Dependent Currents in Isolated Vestibular Afferent Calyx Terminals
J Neurophysiol, January 1, 2006; 95(1): 26 - 32.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
G. S. G. Geleoc, J. R. Risner, and J. R. Holt
Developmental Acquisition of Voltage-Dependent Conductances and Sensory Signaling in Hair Cells of the Embryonic Mouse Inner Ear
J. Neurosci., December 8, 2004; 24(49): 11148 - 11159.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
J. W. Jacklet and D. G. Tieman
Nitric Oxide and Histamine Induce Neuronal Excitability by Blocking Background Currents in Neuron MCC of Aplysia
J Neurophysiol, February 1, 2004; 91(2): 656 - 665.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
H. Bao, W. H. Wong, J. M. Goldberg, and R. A. Eatock
Voltage-Gated Calcium Channel Currents in Type I and Type II Hair Cells Isolated From the Rat Crista
J Neurophysiol, July 1, 2003; 90(1): 155 - 164.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
A. M. Brichta, A. Aubert, R. A. Eatock, and J. M. Goldberg
Regional Analysis of Whole Cell Currents From Hair Cells of the Turtle Posterior Crista
J Neurophysiol, December 1, 2002; 88(6): 3259 - 3278.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
J. M. Goldberg and A. M. Brichta
Functional Analysis of Whole Cell Currents From Hair Cells of the Turtle Posterior Crista
J Neurophysiol, December 1, 2002; 88(6): 3279 - 3292.
[Abstract] [Full Text] [PDF]

Home page
 Ann. N. Y. Acad. Sci.Home page
M. J. CORREIA, K. J. RENNIE, and P. KOO
Return of Potassium Ion Channels in Regenerated Hair Cells: Possible Pathways and the Role of Intracellular Calcium Signaling
Ann. N.Y. Acad. Sci., October 1, 2001; 942(1): 228 - 240.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online