[Isolation and characteristics of calmodulin from the brains of rats with spontaneous genetic hypertension].

Using column chromatography with phenylcepharase, calmodulin was isolated from the brain of rats with spontaneous hypertension (SHR) and control normotensive rats (NKWR). As judged from the findings of electrophoresis in polyacrylamide gel, UV-spectroscopy and spectrofluometry, the obtained samples of calmodulin contained no significant admixture of other proteins. The Ca-binding capacity of calmodulin of the brain of SHR and NKWR estimated by the method of fluorescent probes were identical. There were also no differences in their capacity to interact with troponine I and to activate the Ca-pump of the erythrocytic membrane and phosphodiesterase of the cardiac muscle. A study on the dependence of activity of phosphodiesterase on the protein content of the brain homogenate from SHR and NKWR revealed no differences in the calmodulin levels in this tissue. On the basis of these data a conclusion was made that impairments of the intracellular distribution of calcium in primary hypertension described earlier are not related to disorders in the metabolism of the universal Ca-binding protein-regulator.