RGD Reference Report - Kv1.1 and Kv1.3 channels contribute to the delayed-rectifying K+ conductance in rat choroid plexus epithelial cells. - Rat Genome Database

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Kv1.1 and Kv1.3 channels contribute to the delayed-rectifying K+ conductance in rat choroid plexus epithelial cells.

Authors: Speake, T  Kibble, JD  Brown, PD 
Citation: Speake T, etal., Am J Physiol Cell Physiol 2004 Mar;286(3):C611-20. Epub 2003 Nov 5.
RGD ID: 1300201
Pubmed: PMID:14602579   (View Abstract at PubMed)
DOI: DOI:10.1152/ajpcell.00292.2003   (Journal Full-text)

The choroid plexuses secrete, and maintain the composition of, the cerebrospinal fluid. K+ channels play an important role in these processes. In this study the molecular identity and properties of the delayed-rectifying K+ (Kv) conductance in rat choroid plexus epithelial cells were investigated. Whole cell K+ currents were significantly reduced by 10 nM dendrotoxin-K and 1 nM margatoxin, which are specific inhibitors of Kv1.1 and Kv1.3 channels, respectively. A combination of dendrotoxin-K and margatoxin caused a depolarization of the membrane potential in current-clamp experiments. Western blot analysis indicated the presence of Kv1.1 and Kv1.3 proteins in the choroid plexus. Furthermore, the Kv1.3 and Kv1.1 proteins appear to be expressed in the apical membrane of the epithelial cells in immunocytochemical studies. The Kv conductance was inhibited by 1 microM serotonin (5-HT), with maximum inhibition to 48% of control occurring in 8 min (P < 0.05 by Student's t-test for paired data). Channel inhibition by 5-HT was prevented by the 5-HT2C antagonist mesulergine (300 nM). It was also attenuated in the presence of calphostin C (a protein kinase C inhibitor). The conductance was partially inhibited by 1,2-dioctanoyl-sn-glycerol and phorbol 12-myristate 13-acetate, both of which activate protein kinase C. These data suggest that 5-HT acts at 5-HT2C receptors to activate protein kinase C, which inhibits the Kv channels. In conclusion, Kv1.1 and Kv1.3 channels make a significant contribution to K+ efflux at the apical membrane of the choroid plexus.



Gene Ontology Annotations    Click to see Annotation Detail View

Cellular Component

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Kcna1Ratapical plasma membrane  IDA  RGD 

Molecular Function

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Kcna1Ratdelayed rectifier potassium channel activity  IMP  RGD 
Kcna3Ratdelayed rectifier potassium channel activity  IMP  RGD 
Kcna3Ratoutward rectifier potassium channel activity  IMP  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Kcna1  (potassium voltage-gated channel subfamily A member 1)
Kcna3  (potassium voltage-gated channel subfamily A member 3)


Additional Information