Does histamine have two vasodilator actions on the gastric mucosa?

It has been shown previously that there is a greater gastric mucosal blood flow response to histamine than to gastrin stimulation for similar acid secretory values. We have confirmed these observations under steady state conditions and also shown that the oxygen consumption depends on acid secretion in a similar way for both histamine and gastrin stimulation. Furthermore the degree of oxygen extraction from the gastric circulation is significantly less (p less than 0.001) during histamine stimulation than during gastrin stimulation. This supports the hypothesis that histamine causes a vasodilatation in the gastric mucosa in two ways, one may be linked to secretory activity and the other a pure dilator action.