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Theory of Gastric Ventilation: Hypercapnia Stimulates Gastric Acid Secretion in the Rat
Author(s) -
Held Heather E.,
Landon Carol S.,
Dean Jay B.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.930.1
Subject(s) - hypercapnia , stomach , normocapnia , ventilation (architecture) , gastric acid , anesthesia , respiratory system , medicine , room air distribution , tidal volume , chemistry , mechanical engineering , physics , engineering , thermodynamics
We recently described gastric ventilation, in which hypercapnia stimulates gastric acid and bicarbonate secretion in the gastric lumen, where it produces CO 2 that may be vented through esophagus. This study attempts to correlate respiratory and gastric responses to CO 2 . Rats were implanted with gastric catheters. A pH probe sat in the stomach while animals were in a head‐body plethysmograph. Animals breathed air and air +5% CO 2 while awake (n=4) and anesthetized (n=1). While awake, hypercapnia decreased gastric pH (mean ± SE 3.52 ± 0.35 in air; 3.42 ±0.39 in CO 2 ) and tidal volume (V T , 1.12 ± 0.1 ml in air; 0.83 ± 0.1 ml in CO 2 ) but increased frequency of breathing (f, 98.0 ± 6.2 breaths/min in air; 140.4 ± 7.5 breaths/min in CO 2 ) and minute ventilation (V E , 71.7 ± 8.1 ml/min in air; 124.1 ± 15.1 ml/min in CO 2 ). Isoflurane blunted the hypercapnic ventilatory response (V T 1.35 ml in air, 0.66 ml in CO 2 ; f 41.2 breaths/min air, 36.6 breaths/min CO 2 ; V E 42.9 ml/min in air, 24.0 ml/min in CO 2 ) and the gastric response (pH 1.27 in air, 1.29 in CO 2 ). This shows that systemic pH affects gastric acid secretion, which may explain the observed comorbidity of hypercapnia and gastrointestinal disease. (ONR)