| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Lab Neurophysiology, INSERM U603, Paris, France
* To whom correspondence should be addressed. E-mail: nicole.ropert{at}univ-paris5.fr.
The GABAergic neurons of the nucleus reticularis thalami (nRT) express the type 2 hyperpolarization-activated cAMP-sensitive (HCN2) subunit mRNA, but surprisingly, they were reported to lack the hyperpolarization-activated (Ih) current carried by this subunit. Using the voltage-clamp recordings in the thalamocortical slice preparation of the newborn and juvenile mice (P6-P23), we demonstrate that, in the presence of 1 mM barium (Ba2+), the nRT neurons express a slow hyperpolarization-activated inward current, suggesting that the Ih is present but masked in control conditions by K+ leak currents. We investigate the identity of the hyperpolarization-activated current in the nRT by studying its physiological and pharmacological profile in presence of Ba2+. We show that it has voltage- and time-dependent properties typical of the Ih, that it is blocked by cesium and ZD7288, two blockers of the Ih, and that it is carried both by the K+ and Na+ ions.We could also alter the gating characteristics of the hyperpolarization-activated current in the nRT by adding a non-hydrolysable analog of cAMP to the pipette solution. Finally, using the current-clamp recording, we showed that blocking the hyperpolarization-activated current induced an hyperpolarization correlated with an increase of the Rin of the nRT neurons. In conclusion, our results demonstrate that the nRT neurons express the Ih with slow kinetics similar to those described for the homomeric HCN2 channels and we show that the Ih of the nRT contributes to the excitability of the nRT neurons in normal conditions.
This article has been cited by other articles:
|
|
 |
|
  S. Yang and C. L. Cox Excitatory and anti-oscillatory actions of nitric oxide in thalamus J. Physiol., August 1, 2008; 586(15): 3617 - 3628. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J. Bolivar, D. Tapia, G. Arenas, M. Castanon-Arreola, H. Torres, and E. Galarraga A hyperpolarization-activated, cyclic nucleotide-gated, (Ih-like) cationic current and HCN gene expression in renal inner medullary collecting duct cells Am J Physiol Cell Physiol, April 1, 2008; 294(4): C893 - C906. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. A. Graham, A. M. Brichta, P. R. Schofield, and R. J. Callister Altered potassium channel function in the superficial dorsal horn of the spastic mouse J. Physiol., October 1, 2007; 584(1): 121 - 136. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S.-W. Ying, F. Jia, S. Y. Abbas, F. Hofmann, A. Ludwig, and P. A. Goldstein Dendritic HCN2 Channels Constrain Glutamate-Driven Excitability in Reticular Thalamic Neurons J. Neurosci., August 8, 2007; 27(32): 8719 - 8732. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Debanne, P. Gastrein, and E. Campanac Queer channels in hippocampal basket cells: h-current without sag J. Physiol., July 1, 2006; 574(1): 2 - 2. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
