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


     

J Neurophysiol 69: 2222-2231, 1993;
0022-3077/93 $5.00
This Article
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 Bardoni, R.
Right arrow Articles by Belluzzi, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bardoni, R.
Right arrow Articles by Belluzzi, O.

Journal of Neurophysiology, Vol 69, Issue 6 2222-2231, Copyright © 1993 by APS

ARTICLES

Kinetic study and numerical reconstruction of A-type current in granule cells of rat cerebellar slices

R. Bardoni and O. Belluzzi
Istituto di Fisiologia Generale dell'Universita, Ferrara, Italy.

1. Whole-cell voltage-clamp techniques were used to study voltage-activated transient potassium currents in a large sample (n = 143) of granule cells (GrC) from rat cerebellar slices. Tetrodotoxin (TTX; 0.1 microM) was used to block sodium currents, while calcium current was too small to be seen under ordinary conditions. 2. Depolarizing pulses from -50 mV evoked a slow, sustained outward current, developing with a time constant of 10 ms, inactivating over a time scale of seconds and which could be suppressed by 20 mM tetraethylammonium (TEA). By preventing the Ca2+ inflow, this slow outward current could be further separated into a Ca(2+)-dependent and a Ca(2+)-independent component. 3. After conditioning hyperpolarizations to potentials negative to -60 mV, depolarizations elicited transient outward current, peaking in 1-2 ms and inactivating rapidly (approximately 10 ms at 20 degrees C), showing the overall kinetic characteristics of the A-current (IA). The current activated following third-order kinetics and showed a maximal conductance of 12 nS per cell, corresponding to a normalized conductance of 3.8 nS/pF. 4. IA was insensitive to TEA and to the Ca(2+)-channel blockers. 4-Aminopyridine (4-AP) reduced the A-current amplitude by approximately 20%, and the delayed outward currents by > 80%. 5. Voltage-dependent steady-state inactivation of peak IA was described by a Boltzmann function with a slope factor of 8.4 mV and half-inactivation occurring at -78.8 mV. Activation of IA was characterized by a Boltzmann curve with the midpoint at -46.7 mV and with a slope factor of 19.8 mV. 6. IA activation and inactivation was best fitted by the Hodgkin-Huxley m3h formalism. The rate of activation, tau a, was voltage-dependent, and had values ranging from 0.55 ms at -40 mV to 0.2 ms at +50 mV. Double-pulse experiment showed that development and removal of inactivation followed a single-exponential time course; the inactivation time constant, tau ha, was markedly voltage-dependent and ranged from approximately 10 ms at -40 and -100 mV and 70 ms at -70 mV. 7. A set of continuous equations has been developed describing the voltage-dependence of both the steady-state and time constant of activation and inactivation processes, allowing a satisfactory numerical reconstruction of the A-current over the physiologically significant membrane voltage range.(ABSTRACT TRUNCATED AT 400 WORDS)


This article has been cited by other articles:


Home page
 J. Neurosci.Home page
F. Prestori, P. Rossi, B. Bearzatto, J. Laine, D. Necchi, S. Diwakar, S. N. Schiffmann, H. Axelrad, and E. D'Angelo
Altered Neuron Excitability and Synaptic Plasticity in the Cerebellar Granular Layer of Juvenile Prion Protein Knock-Out Mice with Impaired Motor Control
J. Neurosci., July 9, 2008; 28(28): 7091 - 7103.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
H. H Jerng, K. Kunjilwar, and P. J Pfaffinger
Multiprotein assembly of Kv4.2, KChIP3 and DPP10 produces ternary channel complexes with ISA-like properties
J. Physiol., November 1, 2005; 568(3): 767 - 788.
[Abstract] [Full Text] [PDF]

Home page
 J. Pharmacol. Exp. Ther.Home page
D. L. B. Winkelman, C. L. Beck, D. L. Ypey, and M. E. O'Leary
Inhibition of the A-Type K+ Channels of Dorsal Root Ganglion Neurons by the Long-Duration Anesthetic Butamben
J. Pharmacol. Exp. Ther., September 1, 2005; 314(3): 1177 - 1186.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
F. Jow, Z.-H. Zhang, D. C. Kopsco, K. C. Carroll, and K. Wang
Functional coupling of intracellular calcium and inactivation of voltage-gated Kv1.1/Kv{beta}1.1 A-type K+ channels
PNAS, October 26, 2004; 101(43): 15535 - 15540.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
J. S. Rothman and P. B. Manis
Kinetic Analyses of Three Distinct Potassium Conductances in Ventral Cochlear Nucleus Neurons
J Neurophysiol, June 1, 2003; 89(6): 3083 - 3096.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. Bal and D. Oertel
Potassium Currents in Octopus Cells of the Mammalian Cochlear Nucleus
J Neurophysiol, November 1, 2001; 86(5): 2299 - 2311.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
E. D'Angelo, T. Nieus, A. Maffei, S. Armano, P. Rossi, V. Taglietti, A. Fontana, and G. Naldi
Theta-Frequency Bursting and Resonance in Cerebellar Granule Cells: Experimental Evidence and Modeling of a Slow K+-Dependent Mechanism
J. Neurosci., February 1, 2001; 21(3): 759 - 770.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
R. Shibata, K. Nakahira, K. Shibasaki, Y. Wakazono, K. Imoto, and K. Ikenaka
A-Type K+ Current Mediated by the Kv4 Channel Regulates the Generation of Action Potential in Developing Cerebellar Granule Cells
J. Neurosci., June 1, 2000; 20(11): 4145 - 4155.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. R. Stewart, T. Zigova, and M. B. Luskin
Potassium Currents in Precursor Cells Isolated From the Anterior Subventricular Zone of the Neonatal Rat Forebrain
J Neurophysiol, January 1, 1999; 81(1): 95 - 102.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. Maex and E. D. Schutter
Synchronization of Golgi and Granule Cell Firing in a Detailed Network Model of the Cerebellar Granule Cell Layer
J Neurophysiol, November 1, 1998; 80(5): 2521 - 2537.
[Abstract] [Full Text] [PDF]

Home page
 Learn. Mem.Home page
K. P. Giese, J. F. Storm, D. Reuter, N. B. Fedorov, L.-R. Shao, T. Leicher, O. Pongs, and A. J. Silva
Reduced K+ Channel Inactivation, Spike Broadening, and After-Hyperpolarization in Kvbeta 1.1-Deficient Mice with Impaired Learning
Learn. Mem., September 1, 1998; 5(4): 257 - 273.
[Abstract] [Full Text]

Home page
 J. Neurophysiol.Home page
E. D'Angelo, G. D. Filippi, P. Rossi, and V. Taglietti
Ionic Mechanism of Electroresponsiveness in Cerebellar Granule Cells Implicates the Action of a Persistent Sodium Current
J Neurophysiol, August 1, 1998; 80(2): 493 - 503.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. M. Sanchez, A. Surkis, and C. S. Leonard
Voltage-Clamp Analysis and Computer Simulation of a Novel Cesium-Resistant A-Current in Guinea Pig Laterodorsal Tegmental Neurons
J Neurophysiol, June 1, 1998; 79(6): 3111 - 3126.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
P. Serodio and B. Rudy
Differential Expression of Kv4 K+ Channel Subunits Mediating Subthreshold Transient K+ (A-Type) Currents in Rat Brain
J Neurophysiol, February 1, 1998; 79(2): 1081 - 1091.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
E. D'Angelo, G. De Filippi, P. Rossi, and V. Taglietti
Synaptic Activation of Ca2+ Action Potentials in Immature Rat Cerebellar Granule Cells In Situ
J Neurophysiol, September 1, 1997; 78(3): 1631 - 1642.
[Abstract] [Full Text] [PDF]


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