Myosin and actin from aortae of spontaneously hypertensive and normotensive rats

Contractile proteins were extracted from thoracic aortae of 9-month-old spontaneously hypertensive stroke-prone (SHRSP) and normotensive Wistar Kyoto rats (WKY). The average wet weight of the aortae from SHRSP was approximately 1.6-fold heavier than that of WKY. On polyacrylamide gel electrophoresis of the myofibrillar extracts prepared from normalized, equal weights of aortae of SHRSP and WKY, both the compositions and concentrations of major polypeptides including myosin heavy chains and actin were nearly identical in these extracts. The myosins purified from these extracts contained identical light chains of about 20- and 17 kDa. Proteolytic peptide maps of the heavy chains of myosin from SHRSP were also indistinguishable from those of WKY, suggesting that the same isoforms of myosin are expressed in both aortae. From these results it is suggested that the qualitative differences may be small, if any, between the major contractile proteins in the aortae of SHRSP and those of WKY.