Nitric oxide generated from L-arginine is a messenger for cell- to-cell communication. Abnormalities in nitric oxide release have been implicated in diseases ranging from hypertension and atherosclerosis to septic shock and rheumatoid arthritis. We report here the in vivo and in vitro measurements of nitric oxide in the cardiovascular system using a porphyrinic sensor specific for NO. The sensor has a detection limit 10“9 M, response time of 0.1-10 ms and diameter of 1-20 fi m. Protected by an intravenous catheter or Swan-Ganz catheter, the sensor can be implanted into tissues as well as into the blood stream. Nitric oxide concentrations were measured directly in the heart and also in veins and arteries, ranging in diameter from 100 nm to 5 mm. Nitric oxide production was induced by the action of different physical agents (shear stress, stretching) as well as various chemical substances agonists (bradykinin, acetylcholine, ATP).
We report here the in vitro measurements of nitric oxide in the cardiovascular system using a porphyrinic sensor specific for NO. Nitric oxide concentrations were measured directly in different parts of the heart and also in different arteries and veins, ranging from 100 /um to 5 mm in diameter. Highest NO * concentrations were found in the heart and particularly in the areas of aortic and pulmonary valves. The NO * concentration in the arteries was higher than in the veins. A clearcut positive correlation was obtained by plotting the vessel diameter and production of nitric oxide.
Our main objective was to test whether chronic orthostatic body position induces network changes in the saphenous vein superficial tributary system of the rat. Fourteen male Sprague-Dawley rats were kept in tilted tube cages (45º head-up position) for two weeks to induce chronic gravitational load to their leg veins. Ten animals housed in normal cages and four animals kept in horizontally positioned tube cages served as controls. The whole superficial network of the left saphenous vein was microprepared surgically under anesthesia, superfused with saline and observed under a videomicroscope, while normal flow and pressure were maintained in the lumen. Branching angles, lengths of venous segments and their diameters were measured offline from digitized images using special image-analyzing software. Several branching angles at the popliteal confluence were significantly reduced by 12.5-15.8 %. The in vivo diameter of the main branch (936±34 vs. 805±44 µm) and of one of the popliteal tributaries (776±38 vs. 635±36 µm) increased (p<0.05), comparing vessels from tilted animals with those from normal controls. Maintaining the animals in horizontal tube cages did not induce the above alterations. The increased diameters and reduced branching angles of the saphenous vein network observed are adaptive responses of the venous network to a long-term gravitational load., M. Lóránt, G. L. Nádasy, G. Raffai, E. Monos., and Obsahuje bibliografii