| T-type Ca2+ channels mediate propagation of odor-induced Ca2+ transients in rat olfactory receptor neurons. | |
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MedLine Citation:
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PMID: 17110049 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Propagation of odor-induced Ca(2+) transients from the cilia/knob to the soma in mammalian olfactory receptor neurons (ORNs) is thought to be mediated exclusively by high-voltage-activated Ca(2+) channels. However, using confocal Ca(2+) imaging and immunocytochemistry we identified functional T-type Ca(2+) channels in rat ORNs. Here we show that T-type Ca(2+) channels in ORNs also mediate propagation of odor-induced Ca(2+) transients from the knob to the soma. In the presence of the selective inhibitor of T-type Ca(2+) channels mibefradil (10-15 microM) or Ni(2+) (100 microM), odor- and forskolin/3-isobutyl-1-methyl-xanthine (IBMX)-induced Ca(2+) transients in the soma and dendrite were either strongly inhibited or abolished. The percentage of inhibition of the Ca(2+) transients in the knob, however, was 40-50% less than that in the soma. Ca(2+) transients induced by 30 mM K(+) were partially inhibited by mibefradil, but without a significant difference in the extent of inhibition between the knob and soma. Furthermore, an increase of as little as 2.5 mM in the extracellular K(+) concentration (7.5 mM K(+)) was found to induce Ca(2+) transients in ORNs, and such responses were completely inhibited by mibefradil or Ni(2+). Total replacement of extracellular Na(+) with N-methyl-d-glutamate inhibited none of the odor-, forskolin/IBMX- or 7.5 mM K(+)-induced Ca(2+) transients. Positive immunoreactivity to the Ca(v)3.1, Ca(v)3.2 and Ca(v)3.3 subunits of the T-type Ca(2+) channel was observed throughout the soma, dendrite and knob. These data suggest that involvement of T-type Ca(2+) channels in the propagation of odor-induced Ca(2+) transients in ORNs may contribute to signal transduction and odor sensitivity. |
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Authors:
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S H Gautam; K-I Otsuguro; S Ito; T Saito; Y Habara |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-11-15 |
Journal Detail:
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Title: Neuroscience Volume: 144 ISSN: 0306-4522 ISO Abbreviation: Neuroscience Publication Date: 2007 Jan |
Date Detail:
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Created Date: 2006-12-12 Completed Date: 2007-03-28 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7605074 Medline TA: Neuroscience Country: United States |
Other Details:
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Languages: eng Pagination: 702-13 Citation Subset: IM |
Affiliation:
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Laboratory of Physiology, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. |
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| MeSH Terms | |
Descriptor/Qualifier:
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1-Methyl-3-isobutylxanthine
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pharmacology Aniline Compounds / metabolism Animals Calcium / metabolism* Calcium Channel Blockers / pharmacology Calcium Channels, T-Type / physiology* Dose-Response Relationship, Drug Drug Interactions Forskolin / pharmacology Gene Expression Regulation / drug effects Immunohistochemistry / methods Male Mibefradil / pharmacology Microscopy, Confocal / methods Nickel / pharmacology Odors* Olfactory Bulb / cytology Olfactory Receptor Neurons / physiology* Phosphodiesterase Inhibitors / pharmacology Potassium Chloride / pharmacology Rats Rats, Wistar Time Factors Xanthenes / metabolism |
| Chemical | |
Reg. No./Substance:
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0/Aniline Compounds; 0/Calcium Channel Blockers; 0/Calcium Channels, T-Type; 0/Fluo 4; 0/Phosphodiesterase Inhibitors; 0/Xanthenes; 116644-53-2/Mibefradil; 28822-58-4/1-Methyl-3-isobutylxanthine; 66428-89-5/Forskolin; 7440-02-0/Nickel; 7440-70-2/Calcium; 7447-40-7/Potassium Chloride |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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