Effects of Nifedipine on the Mechanical Properties of Sarcolemma and Modulation of Dynamics of the Increase in the Basal Calcium Level in Fibers of Rat Soleus Muscle under Shortterm Hypogravity Conditions

摘要

It has been shown that the modulation of the mechanical properties of sarcolemma mediated by nifedipine may be related to the dynamics of accumulation of calcium ions under short-term rat hindlimb suspension. The basal calcium level was measured with a fluorescent probe Fluo-4AM, the transverse stiffness of different parts of the contractile apparatus and sarcolemma was estimated by atomic force microscopy, and the content of desmin was determined by gel electrophoresis with immunoblotting. It has been found that nifedipine has a protective effect on muscle fibers under hypogravity by decreasing the degradation of desmin and proteins that determine the transverse stiffness of sarcolemma and the contractile apparatus, and the intensity of the increase in the basal calcium level. It was shown that selective blocking of L-channels leads to an increase in the basal calcium level in intact soleus fibers. At the same time, the transverse stiffness of sar-colemma and the contractile apparatus increases. The mechanism of this increase is still unclear, but it is thought to mediate the protective action of nifedipine.