Dopamine D(1)-like Receptor-Mediated Inhibition of Cl/HCO(3)(-) Exchanger Activity in Rat Intestinal Epithelial IEC-6 Cells is Regulated by G Protein-Coupled Receptor Kinase 6 (GRK 6).
The present study investigated the effect of dopamine D(1)-like receptor stimulation on the Cl(-)/HCO(3)(-) exchange activity in rat intestinal epithelial IEC-6 cells. The Cl(-)/HCO(3)(-) exchange activity was found to be a chloride-dependent, DIDS-sensitive and niflumate-insensitive process. The presence of the SLC26A6 anion exchanger was detected by both RT-PCR and immunoblotting analysis in IEC-6 cells, in which three different small interfering RNAs (siRNAs) targeting SLC26A6 markedly inhibited Cl(-)/HCO(3)(-) exchange. Activation of dopamine D(1)-like receptors with SKF 38393 inhibited Cl(-)/HCO(3)(-) exchanger activity, this being antagonized by the D(1) selective antagonist SKF 83566. However, effects of SKF 38393 were maximal at 5 min of exposure to the agonist and rapidly diminished with no effect at 15 min, suggestive of agonist-induced desensitization of D(1)-like receptors. Pretreatment of cells with heparin, a non-selective inhibitor of G protein-coupled receptor kinases (GRKs), prevented the observed attenuation of SKF 38393-induced inhibition of Cl(-)/HCO(3)(-) exchange. Overnight pretreatment with anti-GRK6A and anti-GRK6B, but not with anti-GRK4 antibodies, prevented the loss of SKF 38393-mediated effects. Both PKA and PKC signaling pathways participate in SKF 38393-mediated inhibition of Cl(-)/HCO(3)(-) exchange. These findings suggest that SLC26A6 is at least one of the anion exchanger's family members responsible for Cl(-)/HCO(3)(-) exchange in IEC-6 cells. Dopamine D(1) receptors in IEC-6 rapidly desensitize to D(1)-like agonist stimulation and GRK 6, but not GRK 4, appear to be involved in agonist-mediated responsiveness and desensitization. Copyright (c) 2006 S. Karger AG, Basel.[1]References
- Dopamine D(1)-like Receptor-Mediated Inhibition of Cl/HCO(3)(-) Exchanger Activity in Rat Intestinal Epithelial IEC-6 Cells is Regulated by G Protein-Coupled Receptor Kinase 6 (GRK 6). Fraga, S., Luo, Y., Jose, P., Zandi-Nejad, K., Mount, D., Soares-da-Silva, P. Cell. Physiol. Biochem. (2006) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
