Ultrastructural variations in frog muscles subjected to sciatectomy.

Fine structural variations in two different types of muscles of frog (Rana cyanophlictis) subjected to sciatectomy were studied electronmicroscopically. Gastrocnemius muscle showed marked myofibrillar disarray and degeneration due to sciatectomy, while sartorius muscle was relatively less affected. The extent of sciatectomy induced fine structural variation was in proportion to the degree of denervation atrophy (as reflected by loss of wet muscle weight) in these muscles. Differences in the degree of degenerative changes in atrophying muscles may be attributed to variations in fiber type composition and stretch effects imposed during swimming movements.

Changes in ascorbic acid content and acetylcholinesterase activity in the muscle of frog following sciatectomy.

Unilateral-sciatectomy for three months in the frog, Rana cyanophlictis resulted in a substantial increase on unit weight basis in the ascorbic acid (ASA) and dehydroascorbic acid (DHA) contents of the sciatectomized gastrocnemius muscle. Diketogulonic acid (DKA) levels did not vary. On whole muscle-weight basis only the ASA level increased. The AChE activity in sciatectomized muscle is significantly lower than that of the control. Partially purified preparation of the AChE from the sciatectomized muscle showed different kinetics compared to that from innervated control. In vitro additions of ASA in physiological concentration to the enzyme assay medium inhibited the AChE activity significantly and the inhibition was an un-competitive type. Reduced activity of the enzyme has been correlated to the increased concentration of ASA in the sciatectomized muscle.