The effect of uridine and inosine on capillary permeability in the rat

The effect of uridine and inosine on capillary permeability in the rat was investigated. Uridine produced a significant expansion of the albumin space which was accompanied by a significant increase in haematocrit indicating a leakage of water and proteins from the intra- to the extravascular compartment. This was attributed to a prominent constrictor effect of this substance on the post-capillary vessels. Inosine, on the contrary, produced an increase of the albumin space which was accompanied by a fall in haematocrit, indicating an expansion of the plasma volume. This was attributed to the vasodilator effect of inosine. It is suggested that these two substances may be involved in the control of the circulation.