Recent observations (Rothschild & Gascon, 1966 have shown that water-soluble, sulphated polysaccharides (cellulose, starch or glycogen sulphates, carrageenin) promote the release of bradykinin when added to the plasma of the rat, guinea-pig or man. Preliminary results (Rothschild, 1967a) indicated that cellulose sulphate, at doses which cause extensive plasma kininogen depletion, was well tolerated by rats or guinea-pigs; these have led to a more detailed study of the pharmacodynamic properties of this compound. In the present investigation changes in arterial blood pressure, total protein and kininogen content, esterolytic and fibrinolytic activity, clotting time, platelet, leucocyte and haematocrit values in plasma or blood of rats treated with cellulose sulphate were investigated. The results obtained permit a better evaluation of the possible usefulness of this polysaccharide as a plasma kininogen-depleting agent in the rat.
METHODSCellulose sulphate was prepared from Whatman ashless cellulose powder according to Astrup, Galsmar & Volkert (1944); this procedure gave greater yields and a better reproducibility of the product than the technique described by Karrer, Koenig & Usteri (1943). Kinin precursor (kininogen) in plasma was determined according to Diniz & Carvalho (1963).Esterolytic activity on benzoyl-arginine ethyl ester (BAEE) was determined by the colorimetric method of Brown (1960). Rapid spontaneous inactivation of the esterase occurred during the separation of plasma; enzymic activity was therefore determined in whole blood added, immediately upon withdrawal, to 5 vol. of the buffered substrate solution employed for incubation. This procedure, which probably did not entirely prevent the spontaneous inactivation of the enzyme, nevertheless permitted the demonstration of a high level of esterolytic activity in the blood of rats treated with cellulose sulphate.Blood clotting times were determined by the Lee & White method, as described by Wintrobe (1961). Total leucocyte counts in peripheral blood were performed using a Neubauer counting chamber. Platelets were estimated in peripheral blood diluted with 1.0% of ammonium oxalate, under the Zeiss phase contrast microscope, using a Fuchs-Rosenthal counting chamber.Total plasma protein was determined according to Mokrasch & McGilvery (1956).Fibrinolytic activity was determined by the bovine fibrin plate method of Astrup & Mullertz (1952). Incubations were performed at room temperature (21°-25°C) for a period of 17 hr. The A. M. ROTHSCHILD bovine thrombin utilized was prepared according to the method of Eagle as described by Hawk, Oser & Summerson (1947).The isolated hindquarters of the rat were perfused under positive pressure with Tyrode solution entering the aorta cannulated just below the renal bifurcation. The perfused fluid was collected at a rate of approximately 0.5 ml./min from the inferior vena cava cannulated at the same level. Histamine was assayed on the isolated atropinized guinea-pig ileum, using a standard of histamine dihydrochloride.Male...