JN Journal of Neurophysiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 80: 2538-2549, 1998;
0022-3077/98 $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 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 Google Scholar
Google Scholar
Right arrow Articles by Baker, M. D.
Right arrow Articles by Bostock, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Baker, M. D.
Right arrow Articles by Bostock, H.

The Journal of Neurophysiology Vol. 80 No. 5 November 1998, pp. 2538-2549
Copyright ©1998 The American Physiological Society

Inactivation of Macroscopic Late Na+ Current and Characteristics of Unitary Late Na+ Currents in Sensory Neurons

Mark D. Baker and Hugh Bostock

Sobell Department of Neurophysiology, Institute of Neurology, London WC1N 3BG, United Kingdom

Baker, Mark D. and Hugh Bostock. Inactivation of macroscopic late Na+ current and characteristics of unitary late Na+ currents in sensory neurons. J. Neurophysiol. 80: 2538-2549, 1998. Na+ currents in adult rat large dorsal root ganglion neurons were recorded during long duration voltage-clamp steps by patch clamping whole cells and outside-out membrane patches. Na+ current present >60 ms after the onset of a depolarizing pulse (late Na+ current) underwent partial inactivation; it behaved as the sum of three kinetically distinct components, each of which was blocked by nanomolar concentrations of tetrodotoxin. Inactivation of one component (late-1) of the whole cell current reached equilibrium during the first 60 ms; repolarizing to -40 or -50 mV from potentials of -30 mV or more positive gave rise to a characteristic increase in current (tau  >=  5 ms), attributed to removal of inactivation. A second component (late-2) underwent slower inactivation (tau  > 80 ms) at potentials more positive than -80 mV, and steady-state inactivation appeared complete at -30 mV. In small membrane patches, bursts of brief openings (gamma  = 13-18 pS) were usually recorded. The distribution of burst durations indicated that two populations of channel were present with inactivation rates corresponding to late-1 and late-2 macroscopic currents. The persistent Na+ current in the whole cell that extended to potentials more positive than -30 mV appeared to correspond to sporadic, brief openings that were recorded in patches (mean open time ~0.1 ms) over a wide potential range. None of the three types of gating described corresponded to activation/inactivation gating overlap of fast transient currents.




This article has been cited by other articles:


Home page
 J. Gen. Physiol.Home page
C. G. Vanoye, C. Lossin, T. H. Rhodes, and A. L. George Jr.
Single-channel Properties of Human NaV1.1 and Mechanism of Channel Dysfunction in SCN1A-associated Epilepsy
J. Gen. Physiol., December 27, 2005; 127(1): 1 - 14.
[Abstract] [Full Text] [PDF]

Home page
 BrainHome page
D. Burke, K. Bartley, I. J. Woodforth, A. Yakoubi, and J. P. H. Stephen
The effects of a volatile anaesthetic on the excitability of human corticospinal axons
Brain, May 1, 2000; 123(5): 992 - 1000.
[Abstract] [Full Text] [PDF]


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