Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness

Yevgenij Yanovsky, Jeffrey Zigman, Anna L. Kernder, Alisa Bein, Ichiro Sakata, Sherri Osborne-Lawrence, Helmut L. Haas, Olga A. Sergeeva

Research output: Contribution to journalArticle

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Abstract

The histaminergic neurons in the tuberomamillary nucleus (TMN) of the posterior hypothalamus are involved in the control of arousal. These neurons are sensitive to hypercapnia as has been shown in experiments examining c-Fos expression, a marker for increased neuronal activity. We investigated the mechanisms through which TMN neurons respond to changes in extracellular levels of acid/CO 2. Recordings in rat brain slices revealed that acidification within the physiological range (pH from 7.4 to 7.0), as well as ammonium chloride (5 mM), excite histaminergic neurons. This excitation is significantly reduced by antagonists of type I metabotropic glutamate receptors and abolished by benzamil, an antagonist of acid sensing ion channels (ASICs) and Na +/Ca 2+ exchanger, or by ouabain which blocks Na +/K + ATPase. We detected variable combinations of 4 known types of ASICs in single TMN neurons, and observed activation of ASICs in single dissociated TMN neurons only at pH lower than 7.0. Thus, glutamate, which is known to be released by glial cells and orexinergic neurons, amplifies the acid/CO 2-induced activation of TMN neurons. This amplification demands the coordinated function of metabotropic glutamate receptors, Na +/Ca 2+ exchanger and Na +/K + ATPase. We also developed a novel HDC-Cre transgenic reporter mouse line in which histaminergic TMN neurons can be visualized. In contrast to the rat, the mouse histaminergic neurons lacked the pH 7.0-induced excitation and displayed only a minimal response to the mGluR I agonist DHPG (0.5 μM). On the other hand, ammonium- induced excitation was similar in mouse and rat. These results are relevant for the understanding of the neuronal mechanisms controlling acid/CO 2-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. Moreover, the new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.

Original languageEnglish (US)
JournalFrontiers in Systems Neuroscience
Issue numberMARCH
DOIs
StatePublished - Mar 21 2012

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Wakefulness
Ammonium Compounds
Protons
Neurons
Acid Sensing Ion Channels
Carbon Monoxide
Sodium-Calcium Exchanger
Metabotropic Glutamate Receptors
Arousal
Acids
Posterior Hypothalamus
Ammonium Chloride
Hepatic Encephalopathy
Hypercapnia
Obstructive Sleep Apnea
Ouabain
Neuroglia
Transgenic Mice
Glutamic Acid

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Cellular and Molecular Neuroscience
  • Cognitive Neuroscience
  • Developmental Neuroscience

Cite this

Yanovsky, Y., Zigman, J., Kernder, A. L., Bein, A., Sakata, I., Osborne-Lawrence, S., ... Sergeeva, O. A. (2012). Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness. Frontiers in Systems Neuroscience, (MARCH). https://doi.org/10.3389/fnsys.2012.00023

Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness. / Yanovsky, Yevgenij; Zigman, Jeffrey; Kernder, Anna L.; Bein, Alisa; Sakata, Ichiro; Osborne-Lawrence, Sherri; Haas, Helmut L.; Sergeeva, Olga A.

In: Frontiers in Systems Neuroscience, No. MARCH, 21.03.2012.

Research output: Contribution to journalArticle

Yanovsky, Y, Zigman, J, Kernder, AL, Bein, A, Sakata, I, Osborne-Lawrence, S, Haas, HL & Sergeeva, OA 2012, 'Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness', Frontiers in Systems Neuroscience, no. MARCH. https://doi.org/10.3389/fnsys.2012.00023
Yanovsky, Yevgenij ; Zigman, Jeffrey ; Kernder, Anna L. ; Bein, Alisa ; Sakata, Ichiro ; Osborne-Lawrence, Sherri ; Haas, Helmut L. ; Sergeeva, Olga A. / Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness. In: Frontiers in Systems Neuroscience. 2012 ; No. MARCH.
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