Decrease in ambient [Cl-] stimulates nitric oxide release from cultured rat mesangial cells

H. Tsukahara, Y. Krivenko, L. C. Moore, M. S. Goligorsky

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32 Citations (Scopus)

Abstract

It has been hypothesized that fluctuations of the ionic composition in the interstitium of juxtaglomerular apparatus (JGA) modulate the function of extraglomerular mesangial cells (MC), thereby participating in tubuloglomerular feedback (TGF) signal transmission. We examined the effects of isosmotic reductions in ambient sodium concentration ([Na+]) and [Cl-] on cytosolic calcium concentration ([Ca2+](i)) in cultured rat MC. Rapid reduction of [Na+] or [Cl-] in the bath induced a concentration-dependent rise in [Ca2+](i). MC are much more sensitive to decreases in ambient [Cl- ] than to [Na+]; a decrease in [Cl-] as small as 14 mM was sufficient to elicit a detectable [Ca2+](i) response. These observations suggest that MC can be readily stimulated by modest perturbations of extracellular [Cl-]. Next, we examined whether activation of MC by lowered ambient [Cl-] influences cellular nitric oxide (NO) production. Using an amperometric NO sensor, we found that a 13 mM decrease in ambient [Cl-] caused a rapid, Ca2+/calmodulin-dependent rise in NO release from MC. This response was not inhibitable by dexamethasone, indicating the involvement of the constitutive rather than the inducible type of NO synthase in MC. In addition, the NO release was blunted by indomethacin pretreatment, suggesting that a metabolite(s) of cyclooxygenase regulates the activation of NO synthase in MC. Our findings that small perturbations in external [Cl-] stimulate MC to release NO, a highly diffusible and rapidly acting vasodilator, provide a possible mechanism to explain the transmission of the signal for the TGF response within the JGA.

Original languageEnglish
Pages (from-to)F190-F195
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume267
Issue number1 36-1
DOIs
Publication statusPublished - 1994

Keywords

  • amperometric nitric oxide sensor
  • chloride ion concentration
  • cytosolic calcium
  • nitric oxide synthase
  • tubuloglomerular feedback

ASJC Scopus subject areas

  • Physiology

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