EFFECTIVENESS OF CALORIC RESTRICTION IN PREVENTING AGE-RELATED-CHANGES IN RAT SKELETAL-MUSCLE

The dihydropyridine receptor (DHPR) and ryanodine receptor (RYR1) are needed for excitation-contraction coupling in skeletal muscle. Previou s studies from this laboratory have shown DHPR-RYR1 uncoupling in SS-m onth-old Fischer 344 x Brown Norway F1 (F344BNF1) rats fed ad libitum. The purpose of the present study is to determine whether caloric rest riction prevents age-related impairments in skeletal muscle function a nd expression of DHPR and RyR1. Bundles of soleus and extensor digitor um longus (EDL) were studied from rats fed ad libitum and on 60 percen t caloric restriction. Significant differences were found in peak twit ch or tetanic tension between the ad libitum and calorie-restricted gr oups in soleus and EDL muscles. A significant increase in the expressi on of DHPR and RyR1 was observed in caloric restricted rats. These res ults show that calorie restriction preserves the mechanical properties of aging hind-limb skeletal muscle and maintains the level of DHPR an d RyR1 in aged F344BNF1 rats fed ad libitum. (C) 1998 Academic Press.