Influences of stress on gastric alkaline secretion in rats.
Influences of restraint plus water-immersion stress on gastric alkaline response and mucosal blood flow were investigated in the rat. Under normal conditions, the stomach secreted alkali at the rate of approximately 1 microEq/15 min in the presence of omeprazole (60 mg/kg i.p.) and responded to mucosal acidification (1000 mM HCI for 10 min) by a significant rise of output (approximately 2.5 microEq/15 min), and the latter process was significantly blocked by indomethacin (5 mg/kg s.c.), quinacrine (100 mg/kg s.c.) and vasopressin (10 unit/kg/hr i.v.). Restraint alone decreased basal rates of HCO3- secretion but had no effect on acid-induced HCO3- output. Additional water-immersion stress further reduced alkaline secretion, totally abolished the increased HCO3- response to acid and significantly suppressed the increase of HCO3- output caused by 16,16-dimethyl prostaglandin E2 (3-30 micrograms/kg s.c.). During restraint stress mucosal blood flow was reduced only by 30% but after exposure to additional water-immersion, it further decreased to about 25% of normal values. Both indomethacin and quinacrine had no effect on mucosal blood flow, whereas vasopressin markedly reduced mucosal blood flow by about 80%. These results suggest that stress not only reduced basal rates of alkaline secretion in the stomach but also impaired the mucosal ability to increase HCO3- output in response to acid. These secretory disorders caused by stress may be attributed to both a decrease of mucosal blood flow and prostaglandin deficiency in the mucosa.
Takeuchi
K
K
Department of Applied Pharmacology, Kyoto Pharmaceutical University, Japan.
Furukawa
O
O
Okada
M
M
Niida
H
H
Okabe
S
S
D000818:Animals; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D007101:Immersion; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009853:Omeprazole / Q000494:pharmacology; D011796:Quinacrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013312:Stress, Physiological / Q000503:physiopathology*; D014667:Vasopressins / Q000494:pharmacology
D014667:Vasopressins; D011796:Quinacrine; D009853:Omeprazole; D007213:Indomethacin