Prevention of age-related V1 myosin isozyme decrement in the adult rat heart.

The present investigation was undertaken to determine whether nifedipine could modulate the age-related relative decline in V1 myosin isozyme. Adult rats at age 24 weeks were treated with nifedipine. Myosin isozyme levels (V1, V2, and V3) at age 36 weeks, after 12 weeks of treatment with nifedipine, were compared with age-matched controls without nifedipine. As a natural effect of aging, the V1 percent was reduced from 63 +/- 6 at 16 wks to 29 +/- 3 at 36 wks (P < 0.001). In the 36 week treated Wistar-Kyoto (WKY) rats, the V1 level was 62 +/- 4, which was 47% higher than the age-matched untreated WKY. The V1 content of 36-week treated rats was the same as that of 16-week untreated rats. We conclude that the myosin isozyme changes occurring with aging can be prevented with nifedipine begun in the young adult rat.