Functional and morphological alterations in the rat stomach following exposure to hypertonic NaCl solution.
We examined the effects of 1 M NaCl as a mild irritant on gastric potential difference (PD), acid secretion, mucosal blood flow (MBF), and DNA synthetic activity in anesthetized rat stomachs and compared these effects with those of 4 M NaCl as a strong irritant. Both 1 M and 4 M NaCl produced a PD reduction (mucosal injury), but the reduced PD recovered faster in the mucosa exposed to 1 M NaCl as compared to 4 M NaCl. Acid secretion ceased after exposure to these hypertonic NaCl solutions, but histamine infusion (8 mg/kg/hr) stimulated acid secretion only in the mucosa exposed to 1 M NaCl. The MBF was significantly increased in response to 1 M NaCl, while exposure to 4 M NaCl had no effect on the MBF. These changes in acid secretion and MBF induced by 1 M NaCl were significantly antagonized by pretreatment with indomethacin (5 mg/kg, s.c.). The levels of PGE2 and 6-keto PGF1 alpha in the corpus mucosa were significantly increased in the stomach exposed to both 1 M and 4 M NaCl, and these increases disappeared in the presence of indomethacin. The rate of [3H]-thymidine incorporation was significantly reduced in the mucosa after exposure to 4 M NaCl, but remained unaltered in the stomach exposed to 1 M NaCl. These results suggest that although both 1 M and 4 M NaCl produced mucosal injury (PD reduction) and enhanced PGs formation, a variety of functional alterations mediated by PGs occurred in response to injury in the stomach exposed to 1 M NaCl. The presence or absence of these functional responses may be associated with the biphasic actions on the gastric mucosa of these hypertonic NaCl solutions as mild and strong irritants.
D000222:Adaptation, Physiological; D000818:Animals; D004247:DNA / Q000096:biosynthesis; D005744:Gastric Acid / Q000378:metabolism; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D007509:Irritants / Q000494:pharmacology; D008297:Male; D011453:Prostaglandins / Q000032:analysis; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*
D007509:Irritants; D011453:Prostaglandins; D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride; D004247:DNA; D007213:Indomethacin