QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, April 7, 2004, 24(14):3694-3702; doi:10.1523/JNEUROSCI.5641-03.2004

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Kang, Y. Articles by Shigemoto, R. Search for Related Content PubMed PubMed Citation Articles by Kang, Y. Articles by Shigemoto, R.

 Previous Article  |  Next Article 

Cellular/Molecular
Bidirectional Interactions between H-Channels and Na⁺–K⁺ Pumps in Mesencephalic Trigeminal Neurons

Youngnam Kang,^1,3 Takuya Notomi,² Mitsuru Saito,¹ Wei Zhang,¹ and Ryuichi Shigemoto^2,3

¹Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan, ²Department of Physiological Sciences, School of Life Science, Graduate University for Advanced Studies (Sokendai), and Division of Cerebral Structure, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan, and ³Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012, Japan

The Na⁺–K⁺ pump current (I_p) and the h-current (I_h) flowing through hyperpolarization-activated channels (h-channels) participate in generating the resting potential. These two currents are thought to be produced independently. We show here bidirectional interactions between Na⁺–K⁺ pumps and h-channels in mesencephalic trigeminal neurons. Activation of I_h leads to the generation of two types of ouabain-sensitive I_p with temporal profiles similar to those of instantaneous and slow components of I_h, presumably reflecting Na⁺ transients in a restricted cellular space. Moreover, the I_p activated by instantaneous I_h can facilitate the subsequent activation of slow I_h. Such counteractive and cooperative interactions were also disclosed by replacing extracellular Na⁺ with Li⁺, which is permeant through h-channels but does not stimulate the Na⁺–K⁺ pump as strongly as Na⁺ ions. These observations indicate that the interactions are bidirectional and mediated by Na⁺ ions. Also after substitution of extracellular Na⁺ with Li⁺, the tail I_h was reduced markedly despite an enhancement of I_h itself, attributable to a negative shift of the reversal potential for I_h presumably caused by intracellular accumulation of Li⁺ ions. This suggests the presence of a microdomain where the interactions can take place. Thus, the bidirectional interactions between Na⁺–K⁺ pumps and h-channels are likely to be mediated by Na⁺ microdomain. Consistent with these findings, hyperpolarization-activated and cyclic nucleotide-modulated subunits (HCN1/2) and the Na⁺–K⁺ pump3 isoform were colocalized in plasma membrane of mesencephalic trigeminal neurons having numerous spines.

Key words: H-channel; Na⁺–K⁺ pump; bidirectional interactions; Na⁺-transient; microdomain; spines; excitability; mesencephalic trigeminal neurons

---

Received Dec 22, 2003; revised March 1, 2004; accepted March 1, 2004.

This article has been cited by other articles:

				T. A. Vander Jagt, J. A. Connor, and C. W. Shuttleworth Localized Loss of Ca2+ Homeostasis in Neuronal Dendrites Is a Downstream Consequence of Metabolic Compromise during Extended NMDA Exposures J. Neurosci., May 7, 2008; 28(19): 5029 - 5039. [Abstract] [Full Text] [PDF]

				H. Sato, Y. Shimanuki, M. Saito, H. Toyoda, T. Nokubi, Y. Maeda, T. Yamamoto, and Y. Kang Differential Columnar Processing in Local Circuits of Barrel and Insular Cortices J. Neurosci., March 19, 2008; 28(12): 3076 - 3089. [Abstract] [Full Text] [PDF]

				Y. Kang, Y. Dempo, A. Ohashi, M. Saito, H. Toyoda, H. Sato, H. Koshino, Y. Maeda, and T. Hirai Nitric Oxide Activates Leak K+ Currents in the Presumed Cholinergic Neuron of Basal Forebrain J Neurophysiol, December 1, 2007; 98(6): 3397 - 3410. [Abstract] [Full Text] [PDF]

				Y. Kang, M. Saito, H. Sato, H. Toyoda, Y. Maeda, T. Hirai, and Y.-C. Bae Involvement of Persistent Na+ Current in Spike Initiation in Primary Sensory Neurons of the Rat Mesencephalic Trigeminal Nucleus J Neurophysiol, March 1, 2007; 97(3): 2385 - 2393. [Abstract] [Full Text] [PDF]

				C.-F. Hsiao, N. Wu, and S. H. Chandler Voltage-Dependent Calcium Currents in Trigeminal Motoneurons of Early Postnatal Rats: Modulation by 5-HT Receptors J Neurophysiol, September 1, 2005; 94(3): 2063 - 2072. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help