Role of luminal Ca2+ on normal and damaged gastric mucosa in the rat.
Influence of luminal Ca2+ on the integrity of normal mucosa and recovery of damaged mucosa in anesthetized rat stomachs was studied using a perfusion system. Changes in the mucosal integrity were monitored by measuring transmucosal potential difference (PD) and luminal pH. EDTA, a Ca2+ chelator, dose-dependently reduced PD and increased luminal pH. Five mM Ca2+ (CaCl2) alone produced no changes in either PD and luminal pH, but the PD which was reduced by 250 mM EDTA was significantly recovered. Ethanol or NaCl concentration-dependently reduced PD, but gradually reverted to baseline levels. While 5 mM Ca2+ or 5 mM EDTA did not influence the reduction in PD with 50% ethanol and 1 M NaCl, these agents either enhanced or delayed the recovery processes in reduced PD, respectively. Five mM Ca2+ enhanced the recovery of PD which was reduced by 50% ethanol plus 5 mM EDTA. Gastric damage induced by 50% ethanol plus 5 mM EDTA was much more severe than that induced by 50% ethanol alone or 50% ethanol plus 5 mM Ca2+. Both 50% ethanol and 1 M NaCl significantly increased Ca2+ contents in the gastric lumen. Luminal Ca2+ appears to play an important role in maintaining mucosal integrity, under normal physiological conditions, and in accelerating the recovery process of damaged mucosa in rat stomachs.
K
K
Takeuchi
Y
Y
Nobuhara
S
S
Okabe
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D004492:Edetic Acid / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D014945:Wound Healing
D007473:Ion Channels; D012462:Saline Solution, Hypertonic; D000431:Ethanol; D004492:Edetic Acid; D002118:Calcium