On the Relative Importance of Aerobic Metabolism in Small Nematode Parasites of the Alimentary Tract I. Oxygen Tensions in the Normal Environment of the Parasites

Abstract

As a preliminary to the study of the relative importance of aerobic mechanisms in the metabolism of Nippostrongylus muris, Nematodirus spathiger, N. filicollis and Haemonchus contortus at O2 pressures of the normal environmental fluids of these parasites, the detn. of O2 in the contents of the small intestine of the rat and sheep, and the abomasum of the sheep, has been carried out. The method used allowed measurements to be made close to the mucosa of the alimentary canal of anesthetized animals in which the circulation was left intact, and the procedure ensured that conditions in the normal gut were very little disturbed. In the small intestine of the rat, O2 tensions varied from 30.2 to 8.9 mm. Hg; these readings were usually lower as distances from the pylorus were increased. O2 was always present in the contents of the small intestine of the sheep close to the mucosa, but in smaller amounts than those found under similar conditions in the rat. As the O2 tensions in regions very close to the intestinal mucosa of rats were influenced by the nature of the gases inspired by the animals, it is apparent that some O2 diffused into the intestinal contents from the blood stream.