Opposite effects of H2-receptors on parietal cells and chief cells. Gastric acid and pepsin secretion stimulated by histamine and food combined in dogs: the role of vagal innervation.

The effect of H2-stimulation and blockade was studied in a dog model which made possible physiological stimulation by food and comparison of vagally innervated and denervated acid and pepsin response at the same time. 5 dogs were equipped with two pouches separated from the stomach, and stimulation was done by histamine as continuous infusion combined with a standard meal--a mixture of liver, heart and bonemeal , 10 g/kg. The response was compared with the effect of H2-blockade, cimetidine 5 g/kg, given 30 min before the meal. H2-agonism stimulated acid secretion and strongly inhibited pepsin secretion, and when H2-antagonism was applied, the effects were quite opposite. The results may explain the great differences in acid and pepsin secretion seen after H2-blockade.