Acute inhibition of the betaine transporter by ATP and adenosine in renal MDCK cells

Stephen A. Kempson, Jason M. Edwards, Alyssa Osborn, Michael Sturek

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Extracellular ATP interacts with purinergic P2 receptors to regulate a range of physiological responses, including downregulation of transport activity in the nephron. ATP is released from cells by mechanical stimuli such as cell volume changes, and autocrine signaling by extracellular ATP could occur in renal medullary cells during diuresis. This was tested in Madin-Darby canine kidney (MDCK) cells, a model used frequently to study P1 and P2 receptor activity. ATP was released within 1 min after transfer from 500 to 300 mosmol/kgH2O medium. A 30-min incubation with ATP produced dose-dependent inhibition (0.01- 0.10 mM) of the renal betaine/GABA transporter (BGT1) with little effect on other osmolyte transporters. Inhibition was reproduced by specific agonists for P2X (α,β-methylene-ATP) and P2Y (UTP) receptors. Adenosine, the final product of ATP hydrolysis, also inhibited BGT1 but not taurine transport. Inhibition by ATP and adenosine was blocked by pertussis toxin and A73122, suggesting involvement of inhibitory G protein and PLC in postreceptor signaling. Both ATP and adenosine (0.1 mM) produced rapid increases in intracellular Ca2+, due to the mobilization of intracellular Ca2+ stores and Ca2+ influx. Blocking these Ca2+ increases with BAPTA-AM also blocked the action of ATP and adenosine on BGT1 transport. Finally, immunohistochemical studies indicated that inhibition of BGT1 transport may be due to endocytic accumulation of BGT1 proteins from the plasma membrane. We conclude that ATP and adenosine, through stimulation of PLC and intracellular Ca2+, may be rapidly acting regulators of BGT1 transport especially in response to a fall in extracellular osmolarity.

Original languageEnglish
JournalAmerican Journal of Physiology - Renal Physiology
Volume295
Issue number1
DOIs
StatePublished - Jul 2008

Fingerprint

Madin Darby Canine Kidney Cells
Adenosine
Adenosine Triphosphate
Kidney
betaine plasma membrane transport proteins
Autocrine Communication
GABA Plasma Membrane Transport Proteins
Purinergic P2 Receptors
Taurine
Diuresis
Nephrons
Pertussis Toxin
Cell Size
GTP-Binding Proteins
Osmolar Concentration
Hydrolysis
Down-Regulation
Cell Membrane

Keywords

  • Endocytosis
  • G proteins
  • Intracellular Ca
  • Madin-Darby canine kidney cells
  • Phospholipase C

ASJC Scopus subject areas

  • Physiology
  • Urology

Cite this

Acute inhibition of the betaine transporter by ATP and adenosine in renal MDCK cells. / Kempson, Stephen A.; Edwards, Jason M.; Osborn, Alyssa; Sturek, Michael.

In: American Journal of Physiology - Renal Physiology, Vol. 295, No. 1, 07.2008.

Research output: Contribution to journalArticle

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