Effects of Chronic Low-Frequency Electrical Stimulation and ß-GPA Feeding on the Aerobic Capacity Related Gene Expression in Rat Plantaris Muscle = Effects of Chronic Low-Frequency Electrical Stimulation and ß-GPA Feeding on the Aerobic Capacity Related Gene Expression in Rat Plantaris Muscle

다국어 초록 (Multilingual Abstract)

Female Sprague Dawley rats were divided into two main groups, lab chow or lab chow with 2% ß-guanidinopropionic acid(ß-GPA). Each main group was subdivided into four chronic low-frequency electrical stimulation(CLFES) groups of 0, 3, 14, or 28 days. Following this treatment the plantaris muscle was evaluated for changes in biochemical properties. There was an increase in oxidative capacity as evidenced by a 200% increase in citrate synthase(CS) and cytochrome oxidase(COX) activity. The mitochondrial RNA processing endonuclease RNA(MRP-RNA) increased by 500% with just 3 days of stimulation and remained at this level or decreased slightly over the rest of the stimulation period. Creatine depletion by feeding ß-GPA induced an 100% increase in CS and COX activity which rose to a 180% increase with CLFES. While CLFES induced a rise in CS and COX which was preceded by elevation in MRP-RNA, creatine depletion alone did not elevate MRP-RNA, yet stimulated an increase in enzyme activity. The level of mRNA for CS and COX subunit III were mainly affected by the application of electrical stimulation, not by chronic creatine depletion. CLFES induced a transformation to more oxidative fibers which was greater in magnitude than the creatine depletion alone, but less than the interaction of CLFES upon ß-GPA fed rats. These data demonstrate that specific challenges to homeostatic balance within skeletal muscle use specific alterations in pre-translational, translational, and post-translational regulation to achieve their adaptive response.