The ultrastructural effects of triparanol on rat atrial muscle

Summary The atrial musculature of rats given the cholesterol inhibitor triparanol (MER/29) (250 mg/kg daily) for 8 days was examined under the electron microscope and compared with that from untreated animals. The sarcoplasmic core of muscle fibers from animals given triparanol exhibited a new formation of sarcoplasmic granules which displayed a crystalline latticework with opaque lines approximately 40–60 Å separated by clear spaces 50–70 Å. They were partially or completely surrounded by a membrane. The crystalline bodies in cardiac muscle fibers were not as numerous as those observed in adrenocortical, testicular interstitial, or luteal cells as reported earlier by the investigators.This research was supported by USPHS Grants HE 12751, NS 05665, and 00690.Recipient of Career Research Development Award 1 K 3 GM 28064.