Blood Flow and Flow Distribution in the Small Intestine of the Cat as Analysed by the Kr⁸⁵Wash‐Out Technique

Abstract

Abstract The blood flow and flow distribution of the small intestine of cat were studied at various levels of vascular smooth muscle tone by means of the Kr 85 wash‐out technique. At “resting” total intestinal blood flow about 80 per cent of flow was distributed to the mucosa‐submucosa, where the flow rate amounted to 40–80 ml/min × 100 g. Blood flow of the muscularis was then 10–20 ml/min × 100 g. As total intestinal blood flow was increased by constant, intra‐arterial infusions of isopropylnoradrenaline a larger and larger part of intestinal blood flow was distributed to a highly vascularized part of the intestine probably located in the submucosa and adjacent parts of the mucosa. At intense vasodilatation (venous outflow 225 ml/min × 100 g) about 60 per cent of total flow passed through these intestinal structures, the blood flow of which amounted to 800–1000 ml/min × 100 g. The blood flow of the rest of the mucosa‐submucosa increased concomitantly to 150–200 ml/min × 100 g and that of the muscularis to 35–40 ml/min × 100 g.