[Changes in the mesenteric microcirculation of rats in acute hypoxic hypoxia]

Hypoxia was induced in rats giving them to inspire gaseous mixture corresponding to an altitude of 6000 m. Arterial and venous vessels of the mesentery, from 9 to 43 mum in diameter, were studied; their diameter, blood pressure and blood flow velocity in them were measured. Arterial microvessels proved to dilate in hypoxia. The maximal increase in their diameter (by 3-5 mum) occurred during the first 3-5 min after the gaseous mixture was given to inspire. Blood pressure and blood flow velocity in these vessels decreased during the whole course of the experiment.