Dissertation / PhD Thesis

PreJuSER-44167

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Charakterisierung von hyperpolarisationsaktivierten und zyklisch Nukleotid-gesteuerten Ionenkanälen (HCN-Kanäle) in der Retina und im Gehirn der Ratte

Scholten, A. (Corresponding author)FZJ*

2001
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/20245

Report No.: Juel-3936

Abstract: Hyperpolarization-activated and cyclic nucleotide-gated channels (HCN-channels) have been characterized electrophysiologically in numerous tissues. They play a fundamental role in shaping the autonomous rhythmic activity of pacemaker-cells. In many neurons, HCN-channels co-determine resting potential and membrane conductance and thereby play an important role in the integrative behavior of neurons and the sensitivity to synaptic input. Recently, four different genes for HCN-channels have been identified in all mammalian species investigated. But little is known about the cellular expression pattem of HCN-channel subtypes, and their function in these cells. Moreover, it is not clear, whether or not the different subtypes form heteromeric channels. In the present study specific antibodies against all four HCN-channel subtypes were raised. Biochemical studies revealed, that all four HCN-channel subtypes are expressed in the rat retina, and in the rat and mouse brain in glycosylated form. The sizes of deglycosylated channel proteins are in good agreement with the estimated molecular weights of the HCN-channels. Other posttranscriptional or posttranslational modifications, that would change the sizes of the proteins in westemblot experiments, were not detected. Immunohistochemical stainings of the rat retina showed different expression patterns for the four HCN-channel subtypes: In most bipolar celltypes only one HCN-channel subtype was detected. Only in type 5 bipolar cells and some ganglion cells HCN1 and HCN4 are co-localized and might form heteromeric channels. Immunoprecipitation experiments were performed to detect heteromeric HCN1/HCN4-complexes in co-transfected HEK 293-cells and in the rat retina. But the results were not unequivocal. To reveal the function of HCN-channels in different brain neurons, first investigation an the cellular expression pattern of the HCN-channels in the rat brain were started. As in the retina the HCN-channel subtypes are differentially expressed. The electrophysiological properties of the HCN-channel subtypes, as well as their cellular and subcellular localization indicate some of the physiological functions of HCN-channels in different cell types. We can now search for other ion channels or receptors, that interact with the HCN-channels. This knowledge will help to elucidate the role of HCN-channels in signal cascades or other cellular processes.

Note: Record converted from VDB: 12.11.2012
Note: Köln. Univ., Diss. 2001

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Contributing Institute(s):

1. Zelluläre Signalverarbeitung (IBI-1)

Research Program(s):

1. Zelluläre Signalverarbeitung (42.20.1)

Appears in the scientific report 2001

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Database coverage:

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