Document Detail

Molecular identification of Kvalpha subunits that contribute to the oxygen-sensitive K+ current of chemoreceptor cells of the rabbit carotid body.
MedLine Citation:
PMID:  12122138     Owner:  NLM     Status:  MEDLINE    
Rabbit carotid body (CB) chemoreceptor cells possess a fast-inactivating K+ current that is specifically inhibited by hypoxia. We have studied the expression of Kvalpha subunits, which might be responsible for this current. RT-PCR experiments identified the expression of Kv1.4, Kv3.4, Kv4.1 and Kv4.3 mRNAs in the rabbit CB. There was no expression of Kv3.3 or Kv4.2 transcripts. Immunocytochemistry with antibodies to tyrosine hydroxylase (anti-TH) and to specific Kv subunits revealed the expression of Kv3.4 and Kv4.3 in chemoreceptor cells, while Kv1.4 was only found in nerve fibres. Kv4.1 mRNA was also found in chemoreceptor cells following in situ hybridization combined with anti-TH antibody labelling. Kv4.1 and Kv4.3 appeared to be present in all chemoreceptor cells, but Kv3.4 was only expressed in a population of them. Electrophysiological experiments applying specific toxins or antibodies demonstrated that both Kv3.4 and Kv4.3 participate in the oxygen-sensitive K+ current of chemoreceptor cells. However, toxin application experiments confirmed a larger contribution of members of the Kv4 subfamily. [Ca2+]i measurements under hypoxic conditions and immunocytochemistry experiments in dispersed CB cells demonstrated the expression of Kv3.4 and Kv4.3 in oxygen-sensitive cells; the presence of Kv3.4 in the chemoreceptor cell membrane was not required for the response to low PO2. In summary, three Kv subunits (Kv3.4, Kv4.1 and Kv4.3) may be involved in the fast-inactivating outward K+ current of rabbit CB chemoreceptor cells. The homogeneous distribution of the Kv4 subunits in chemoreceptor cells, along with their electrophysiological properties, suggest that Kv4.1, Kv4.3, or their heteromultimers, are the molecular correlate of the oxygen-sensitive K+ channel.
Diego Sanchez; Jose R López-López; M Teresa Pérez-García; Gloria Sanz-Alfayate; Ana Obeso; Maria D Ganfornina; Constancio Gonzalez
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  542     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-17     Completed Date:  2003-02-10     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  369-82     Citation Subset:  IM    
Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Valladolid, Spain.
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MeSH Terms
Base Sequence
Carotid Body / cytology,  physiology*
Cells, Cultured
Chemoreceptor Cells / physiology*
DNA Primers
Kv1.4 Potassium Channel
Membrane Potentials / physiology
Neurons / cytology,  physiology*
Patch-Clamp Techniques
Potassium / physiology*
Potassium Channels / chemistry,  genetics,  physiology*
Potassium Channels, Voltage-Gated*
Protein Subunits / genetics,  physiology
RNA, Messenger / genetics
Shal Potassium Channels
Reg. No./Substance:
0/DNA Primers; 0/Kv1.4 Potassium Channel; 0/Potassium Channels; 0/Potassium Channels, Voltage-Gated; 0/Protein Subunits; 0/RNA, Messenger; 0/Shal Potassium Channels; 7440-09-7/Potassium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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