help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
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
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mao, B.-Q.
Right arrow Articles by Victor, J. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mao, B.-Q.
Right arrow Articles by Victor, J. D.
Biophysical Journal 84:2756-2767 (2003)
© 2003 The Biophysical Society

Role of Hyperpolarization-Activated Currents for the Intrinsic Dynamics of Isolated Retinal Neurons

Bu-Qing Mao*, Peter R. MacLeish{dagger} and Jonathan D. Victor*

* Department of Neurology and Neuroscience and {dagger} Department of Ophthalmology-Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, New York 10021

Correspondence: Address reprint requests to Jonathan D. Victor, Dept. of Neurology and Neuroscience, Weill Medical College of Cornell University, 1300 York Ave., New York, NY 10021. Tel.: 212-746-2343; Fax: 212-746-8984; E-mail: jdvicto{at}med.cornell.edu.

The intrinsic dynamics of bipolar cells and rod photoreceptors isolated from tiger salamanders were studied by a patch-clamp technique combined with estimation of effective impulse responses across a range of mean membrane voltages. An increase in external K+ reduces the gain and speeds the response in bipolar cells near and below resting potential. High external K+ enhances the inward rectification of membrane potential, an effect mediated by a fast, hyperpolarization-activated, inwardly rectifying potassium current (KIR). External Cs+ suppresses the inward-rectifying effect of external K+. The reversal potential of the current, estimated by a novel method from a family of impulse responses below resting potential, indicates a channel that is permeable predominantly to K+. Its permeability to Na+, estimated from Goldman-Hodgkin-Katz voltage equation, was negligible. Whereas the activation of the delayed-rectifier K+ current causes bandpass behavior (i.e., undershoots in the impulse responses) in bipolar cells, activation of the KIR current does not. In contrast, a slow hyperpolarization-activated current (Ih) in rod photoreceptors leads to pronounced, slow undershoots near resting potential. Differences in the kinetics and ion selectivity of hyperpolarization-activated currents in bipolar cells (KIR) and in rod photoreceptors (Ih) confer different dynamical behavior onto the two types of neurons.




This article has been cited by other articles:


Home page
 J. Neurosci.Home page
R. Narayanan and D. Johnston
The h Channel Mediates Location Dependence and Plasticity of Intrinsic Phase Response in Rat Hippocampal Neurons
J. Neurosci., May 28, 2008; 28(22): 5846 - 5860.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
A. Suryanarayanan and M. M. Slaughter
Synaptic Transmission Mediated by Internal Calcium Stores in Rod Photoreceptors
J. Neurosci., February 8, 2006; 26(6): 1759 - 1766.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
P. Koulen, J. Liu, E. Nixon, and C. Madry
Interaction between mGluR8 and Calcium Channels in Photoreceptors Is Sensitive to Pertussis Toxin and Occurs Via G Protein {beta}{gamma} Subunit Signaling
Invest. Ophthalmol. Vis. Sci., January 1, 2005; 46(1): 287 - 291.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2003 by the Biophysical Society.