[Calcitonin gene-related peptide in normotensive and spontaneously hypertensive rats]

Using specific radioimmunoassay, radioimmunoreceptor analysis and gel filtration, we found that calcitonin gene-related peptides (CGRP) were distributed in various tissues of normotensive rat (WKY) and spontaneously hypertensive rat (SHR), the highest content was in the lumbar spinal cord (1197 +/- 94.8 pg/mg tissue), the lowest in the auricle (15.0 +/- 2.1 pg/mg tissue). Compared with WKY, the plasma CGRP concentration decreased and the CGRP content in abdominal aorta and hypothalamus increased in SHR. By gel filtration, it showed that only one major molecular form of CGRP was present in the tissues. The CGRP specific binding sites were present both in SHR and WKY hearts, but the number of CGRP binding sites in SHR heart was higher and the binding affinity lower than those in WKY heart. Besides, CGRP can reduce the mean arterial pressure (MAP) in the SHR in a dose-dependent way. The above data indicated that CGRP may play an important role in the pathogenesis of hypertension and exert possibly a therapeutic effect on hypertension.