Dopamine D-1-like receptor-mediated inhibition of Cl-/HCO3- exchanger activity in rat intestinal epithelial IEC-6 cells is regulated by G protein-coupled receptor kinase 6 (GRK 6)

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Sonia Fraga (Author) FFUP; Luo, YJ (Author) Other; Jose, PA (Author) Other; Zandi Nejad, K (Author) Other; Mount, DB (Author) Other; soares-da-silva, p (Author) FMUP

Journal

Title: Cellular Physiology and Biochemistry

Vol. 18

Pages: 347-360

ISSN: 1015-8987

Publisher: Cell Physiol Biochem Press

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-004-P9R

DOI: 10.1159/000097612

Abstract (EN): The present study investigated the effect of dopamine D-1-like receptor stimulation on the Cl-/HCO3- exchange activity in rat intestinal epithelial IEC-6 cells. The Cl-/ HCO3-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-/HCO3(-) exchange. Activation of dopamine D-1-like receptors with SKF 38393 inhibited Cl-/HCO3- 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-/HCO3- exchange. Overnight pretreatment with anti-GRK6A and antiGRK6B, 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-/HCO3- exchange. These findings suggest that SLC26A6 is at least one of the anion exchanger's family members responsible for Cl-/HCO3- 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14