Digestive Diseases and Sciences

, Volume 37, Issue 5, pp 737–743 | Cite as

Role of capsaicin-sensitive sensory nerves in acid-induced bicarbonate secretion in rat stomach

  • Koji Takeuchi
  • Koji Ueshima
  • Jiro Matsumoto
  • Susumu Okabe
Original Articles


The effect of capsaicin-sensitive afferent nerves on the alkaline secretory response induced by mucosal acidification was investigated in theex vivo stomachs of anesthetized rats. The stomach was mounted on a Lucite chamber and perfused with saline (pH 4.5) in the absence of acid secretion (omeprazole pretreatment: 60 mg/kg, intraperitoneal), and luminal pH and transmucosal potential difference (PD) were monitored simultaneously. Under these conditions the gastric mucosa responded to intravenous infection of prostaglandin E2 (PGE2: 300 μg/kg) and mucosal acidification (0.2 N HCl for 10 min) by a significant increase of pH with a slight decrease of PD; the HCO3 output was 9.2±0.7 μmol and 8.4±0.8 μmol, respectively. The increased pH and HCO3 responses were significantly inhibited by prior administration of indomethacin (5 mg/kg, subcutaneously) or chemical deafferentation following capsaicin injections (total dose: 100 mg/kg, subcutaneously), whereas those induced by PGE2 remained unchanged after either treatment. On the other hand, the mucosal application of capsaicin (0.3–6 mg/ml) increased the luminal pH and HCO3 output in a concentration-related manner, and this action was also significantly attenuated by either indomethacin or chemical deafferentation of capsaicin-sensitive sensory neurons. These results suggest that capsaicin-sensitive sensory nerves may be involved in the mechanism of acid-induced HCO3 secretion in the stomach, in addition to endogenous PGs, and these two pathways may interact somewhere in the stimulatory process.

Key Words

capsaicin gastric mucosa HCO3 secretion mucosal acidification sensory nerve 


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Copyright information

© Plenum Publishing Corporation 1992

Authors and Affiliations

  • Koji Takeuchi
    • 1
  • Koji Ueshima
    • 1
  • Jiro Matsumoto
    • 1
  • Susumu Okabe
    • 1
  1. 1.Department of Applied PharmacologyKyoto Pharmaceutical UniversityKyoto 607Japan

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