JN Add DOIs to your references at manuscript stage!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 85: 580-593, 2001;
0022-3077/01 $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 (24)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kjaerulff, O.
Right arrow Articles by Kiehn, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kjaerulff, O.
Right arrow Articles by Kiehn, O.

The Journal of Neurophysiology Vol. 85 No. 2 February 2001, pp. 580-593
Copyright ©2001 by the American Physiological Society

5-HT Modulation of Multiple Inward Rectifiers in Motoneurons in Intact Preparations of the Neonatal Rat Spinal Cord

Ole Kjaerulff and Ole Kiehn

Division of Neurophysiology, Department of Medical Physiology, The Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark

Kjaerulff, Ole and Ole Kiehn. 5-HT Modulation of Multiple Inward Rectifiers in Motoneurons in Intact Preparations of the Neonatal Rat Spinal Cord. J. Neurophysiol. 85: 580-593, 2001. This study introduces novel aspects of inward rectification in neonatal rat spinal motoneurons (MNs) and its modulation by serotonin (5-HT). Whole cell tight-seal recordings were made from MNs in an isolated lumbar spinal cord preparation from rats 1-2 days of age. In voltage clamp, hyperpolarizing step commands were generated from holding potentials of -50 to -40 mV. Discordant with previous reports involving slice preparations, fast inward rectification was commonly expressed and in 44% of the MNs co-existed with a slow inward rectification related to activation of Ih. The fast inward rectification is likely caused by an IKir. Thus it appeared around EK and was sensitive to low concentrations (100-300 µM) of Ba2+ but not to ZD 7288, which blocked Ih. Both IKir and Ih were inhibited by Cs2+ (0.3-1.5 mM). Extracellular addition of 5-HT (10 µM) reduced the instantaneous conductance, most strongly at membrane potentials above EK. Low [Ba2+] prevented the 5-HT-induced instantaneous conductance reduction below, but not that above, EK. This suggests that 5-HT inhibits IKir, but also other instantaneous conductances. The biophysical parameters of Ih were evaluated before and under 5-HT. The maximal Ih conductance, Gmax, was 12 nS, much higher than observed in slice preparations. Gmax was unaffected by 5-HT. In contrast, 5-HT caused a 7-mV depolarizing shift in the activation curve of Ih. Double-exponential fits were generally needed to describe Ih activation. The fast and slow time constants obtained by these fits differed by an order of magnitude. Both time constants were accelerated by 5-HT, the slow time constant to the largest extent. We conclude that spinal neonatal MNs possess multiple forms of inward rectification. Ih may be carried by two spatially segregated channel populations, which differ in kinetics and sensitivity to 5-HT. 5-HT increases MN excitability in several ways, including inhibition of a barium-insensitive leak conductance, inhibition of IKir, and enhancement of Ih. The quantitative characterization of these effects should be useful for further studies seeking to understand how neuromodulation prepares vertebrate MNs for concerted behaviors such as locomotor activity.




This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
T. Endo and O. Kiehn
Asymmetric Operation of the Locomotor Central Pattern Generator in the Neonatal Mouse Spinal Cord
J Neurophysiol, December 1, 2008; 100(6): 3043 - 3054.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
S. M. ElBasiouny and V. K. Mushahwar
Suppressing the excitability of spinal motoneurons by extracellularly applied electrical fields: insights from computer simulations
J Appl Physiol, November 1, 2007; 103(5): 1824 - 1836.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
I. A. Rybak, N. A. Shevtsova, M. Lafreniere-Roula, and D. A. McCrea
Modelling spinal circuitry involved in locomotor pattern generation: insights from deletions during fictive locomotion
J. Physiol., December 1, 2006; 577(2): 617 - 639.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
G. Zhong, M. Diaz-Rios, and R. M. Harris-Warrick
Serotonin Modulates the Properties of Ascending Commissural Interneurons in the Neonatal Mouse Spinal Cord
J Neurophysiol, March 1, 2006; 95(3): 1545 - 1555.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
S. Chevallier, F. Nagy, and J.-M. Cabelguen
Cholinergic control of excitability of spinal motoneurones in the salamander
J. Physiol., February 1, 2006; 570(3): 525 - 540.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
M. Manuel, C. Meunier, M. Donnet, and D. Zytnicki
How Much Afterhyperpolarization Conductance Is Recruited by an Action Potential? A Dynamic-Clamp Study in Cat Lumbar Motoneurons
J. Neurosci., September 28, 2005; 25(39): 8917 - 8923.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
S. J. B. Butt, L. Lundfald, and O. Kiehn
EphA4 defines a class of excitatory locomotor-related interneurons
PNAS, September 27, 2005; 102(39): 14098 - 14103.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
H. Nishimaru, C. E. Restrepo, J. Ryge, Y. Yanagawa, and O. Kiehn
Mammalian motor neurons corelease glutamate and acetylcholine at central synapses
PNAS, April 5, 2005; 102(14): 5245 - 5249.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
A. R. Mercer, P. Kloppenburg, and J. G. Hildebrand
Plateau Potentials in Developing Antennal-Lobe Neurons of the Moth, Manduca sexta
J Neurophysiol, April 1, 2005; 93(4): 1949 - 1958.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
M. G. Maltenfort and T. M. Hamm
Estimation of the Electrical Parameters of Spinal Motoneurons Using Impedance Measurements
J Neurophysiol, September 1, 2004; 92(3): 1433 - 1444.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
M. A. Madriaga, L. C. McPhee, T. Chersa, K. J. Christie, and P. J. Whelan
Modulation of Locomotor Activity by Multiple 5-HT and Dopaminergic Receptor Subtypes in the Neonatal Mouse Spinal Cord
J Neurophysiol, September 1, 2004; 92(3): 1566 - 1576.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
J. Gilmore and B. Fedirchuk
The excitability of lumbar motoneurones in the neonatal rat is increased by a hyperpolarization of their voltage threshold for activation by descending serotonergic fibres
J. Physiol., July 1, 2004; 558(1): 213 - 224.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
B. Fedirchuk and Y. Dai
Monoamines increase the excitability of spinal neurones in the neonatal rat by hyperpolarizing the threshold for action potential production
J. Physiol., June 1, 2004; 557(2): 355 - 361.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
J.-F. Perrier, A. Alaburda, and J. Hounsgaard
5-HT1A receptors increase excitability of spinal motoneurons by inhibiting a TASK-1-like K+ current in the adult turtle
J. Physiol., April 15, 2003; 548(2): 485 - 492.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
S. Tanaka, N. Wu, C.-F. Hsaio, J. Turman Jr., and S. H. Chandler
Development of Inward Rectification and Control of Membrane Excitability in Mesencephalic V Neurons
J Neurophysiol, March 1, 2003; 89(3): 1288 - 1298.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
S. J. B. Butt, R. M. Harris-Warrick, and O. Kiehn
Firing Properties of Identified Interneuron Populations in the Mammalian Hindlimb Central Pattern Generator
J. Neurosci., November 15, 2002; 22(22): 9961 - 9971.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
M. Mock, C. Schwarz, and P. Thier
Serotonergic Control of Cerebellar Mossy Fiber Activity by Modulation of Signal Transfer by Rat Pontine Nuclei Neurons
J Neurophysiol, August 1, 2002; 88(2): 549 - 564.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
J. E Sirois, C. Lynch III, and D. A Bayliss
Convergent and reciprocal modulation of a leak K+ current and Ih by an inhalational anaesthetic and neurotransmitters in rat brainstem motoneurones
J. Physiol., June 15, 2002; 541(3): 717 - 729.
[Abstract] [Full Text] [PDF]


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