[Longitudinal oxygen gradients in cerebra micro vessels in acute anaemia in rats].

Using a fine-tip oxygen microelectrodes the longitudinal gradients of oxygen tension (pO2) have been studied in small arterioles (with lumen diameter in control of 5 +/- 20 microm) and in capillaries of the rat brain cortex during stepwise decrease of the blood haemoglobin concentration [Hb] from control [Hb]--14.4 +/- 0.3 g/dl to 10.

Tissue oxygen tension profiles close to brain arterioles and venules in the rat cerebral cortex during the development of acute anemia.

Acute anemia (stages 1 and 2) led to decreases in pO2 at the walls of radial venules (lumen diameter 13.1 +/- 0.5 microm) and in the tissues at distances of up to 40 mum from the walls, indicating increased extraction of oxygen from the blood by the smallest microvessels.

[Profiles next to the walls of the rat cerebral arterioles and venules in acute anemia].

Acute anemia was shown to result in increase of pO2 in the wall of radial arterioles (with lumen diameter of 14.7 +/- 0.9 microm) and in the tissue near the studied arterioles, while decreasing as compared to control values at the distance 60 urn from the vessel wall.

Transmural oxygen tension gradients in rat cerebral cortex arterioles.

Modified needle oxygen microelectrodes and vital microscopy were used to measure transmural oxygen tension gradients (PO2) in pial arterioles with lumen diameters of 20-90 microm. A relationship between the magnitude of the transmural PO2 gradient and arteriole wall tone was found: in control conditions, PO2 gradients were 1.17 +/- 0.

[Transmural gradients of oxygen tension on cerebral microvessels in rats].

Using modified oxygen needle microelectrodes, vital microscopy with video-recording facilities, measurements of tissue oxygen tension (PO2) profiles near the cortical arterioles and transmural PO2 gradients on pial arterioles of the rat were performed. At control transmural PO2 gradient averaged 1.17 +/- 0.