Stimulation by sparkling water of gastroduodenal HCO3- secretion in rats

Med Sci Monit. 2009 Dec;15(12):BR349-56.


Background: We examined the effect of sparkling water on gastroduodenal HCO3- secretion in rats and investigated the factors involved in these responses.

Material/methods: Under urethane anesthesia, a chambered stomach or a proximal duodenal loop was superfused with saline, and HCO3- secretion was measured at pH 7.0 using a pH-stat.

Results: The amount of CO2 in sparkling water was about 7.2 g/L. The mucosal exposure with sparkling water increased the secretion of HCO3- in both the stomach and duodenum. The HCO3- response in the duodenum was partially inhibited by indomethacin, acetazolamide or sensory deafferentation and was totally abolished by the co-administration of the former two agents. By contrast, the response in the stomach was almost totally inhibited by acetazolamide and partially mitigated by indomethacin but not sensory deafferentation. DIDS [an inhibitor of the Cl-/HCO3- exchanger (AE) and the Na+-HCO3- cotransporter (NBC)] and DMA [an inhibitor of the Na+/H+ exchanger 1 (NHE1)] partially mitigated the HCO3- response in the duodenum but not the stomach. The mucosal application of sparkling water increased prostaglandin E2 content in these tissues.

Conclusions: Sparkling water stimulates HCO3- secretion in both the stomach and the duodenum, but the mechanisms involved differ in these two tissues; the response in the former is mainly due to the intracellular supply of HCO3- with the aid of carbonic anhydrase, while in the latter the response is dependent on the NHE1, AE and NBC, and is mediated by endogenous prostaglandins as well as capsaicin-sensitive afferent neurons, in addition to the intracellular supply of HCO3-.

MeSH terms

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
  • Acetazolamide / pharmacology
  • Afferent Pathways / drug effects
  • Afferent Pathways / physiology
  • Amiloride / analogs & derivatives
  • Amiloride / pharmacology
  • Animals
  • Bicarbonates / metabolism*
  • Capsaicin / pharmacology
  • Carbonated Beverages / toxicity*
  • Dinoprostone / metabolism
  • Duodenum / drug effects
  • Duodenum / metabolism
  • Gastric Mucosa / drug effects*
  • Gastric Mucosa / metabolism*
  • Indomethacin / pharmacology
  • Intestinal Mucosa / drug effects*
  • Intestinal Mucosa / metabolism*
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Water / pharmacology*


  • Bicarbonates
  • Water
  • 5-dimethylamiloride
  • Amiloride
  • Dinoprostone
  • Acetazolamide
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • Capsaicin
  • Indomethacin