Mechanism of gastric hyperemia induced by intragastric hypertonic saline in rats.
BACKGROUND
Intragastric hypertonic (2 mol/L) saline produces injury in the gastric mucosa and a significant increase in gastric blood flow (hyperemia) in anesthetized rats. We studied the mechanism of this hyperemia.


METHODS
Rats were treated with intravenous boluses of NG-nitro-L-arginine methyl ester (3 mg/kg) to block synthesis of endogenous nitric oxide, pyrilamine (1 mg/kg) to inhibit H1 receptors, or indomethacin (5 mg/kg) to block synthesis of endogenous prostaglandins during blood flow studies or with subcutaneous capsaicin (125 mg/kg) 10-14 days before blood flow studies to ablate capsaicin-sensitive afferent nerves. Gastric mucosal blood flow was measured by hydrogen gas clearance before and during intragastric administration of 2 mol/L saline.


RESULTS
The gastric hyperemia induced by intragastric 2 mol/L saline was completely blocked only by indomethacin. The associated gastric mucosal damage was increased significantly.


CONCLUSIONS
In the rat stomach, the gastric hyperemia induced by intragastric 2 mol/L saline is mediated by endogenous prostaglandins and plays a protective role. Endogenous nitric oxide, H1 receptors, and capsaicin-sensitive afferent nerves are not involved in this protective hyperemia.
Endoh
K
K
Research and Medical Services, Sepulveda Veterans Administration Medical Center, California.
Kao
J
J
Domek
M J
MJ
Leung
F W
FW
D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006940:Hyperemia / Q000139:chemically induced* / Q000473:pathology; D007213:Indomethacin / Q000494:pharmacology; D007441:Intubation, Gastrointestinal; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000494:pharmacology; D013270:Stomach / Q000098:blood supply* / Q000473:pathology
D012462:Saline Solution, Hypertonic; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin