[Seasonal changes in the composition of the titin isoforms in muscles of hibernating ground squirrels].
An electrophoretic study of changes in the content of intact titin isoforms, N2B-, N2BA-, N2A-titins and T2 in skeletal and cardiac muscles of ground squirrel (Spermophillus undulatus) in different periods: summer activity, autumn activity, hibernation, arousal, and winter activity has been carried out. In atriums and ventricles of autumn activity ground squirrels, an increase (approximately 1.5 times) in the N2BA-to-N2B ratio in comparison with that in cardiac muscle of summer activity ground squirrels has been observed. During hibernation, the decrease in the relative content of N2B,- N2BA-titins and T2 in cardiac muscle and of N2A-titin and T2 in skeletal muscles has been tested against the background of preservation of the relative amount of intact titin isoforms. During arousal of ground squirrel and in short-time period of winter activity, a rapid restoration in the content of N2B,- N2BA-, N2A-titins and T2 in muscles has been observed. In this case, in cardiac muscle of hibernating, arousing and winter active ground squirrels, the increased N2BA-to-N2B ratio has been preserved. The changes in the titin content are discussed in the context of adaptation of ground squirrels to hibernation.
Electrophoresis, Polyacrylamide Gel
Pub Type(s)English Abstract
Research Support, Non-U.S. Gov't