Microcurrent electrical neuromuscular stimulation (MENS) is
known as an extracellular stimulus for the regeneration of injured
skeletal muscle in sports medicine. However, the effects of
MENS-associated increase in muscle protein content are not fully
clarified. The purpose of this study was to investigate the effects
of MENS on the muscular protein content, intracellular signals,
and the expression level of caveolin-3 (Cav-3), tripartite motifcontaining 72 (TRIM72) and MM isoenzyme of creatine kinase
(CK-MM) in skeletal muscle using cell culture system. C2C12
myotubes on the 7th day of differentiation phase were treated
with MENS (intensity: 10-20 μA, frequency: 0.3 Hz, pulse width:
250 ms, stimulation time: 15-120 min). MENS-associated
increase in the protein content of myotubes was observed,
compared to the untreated control level. MENS upregulated the
expression of Cav-3, TRIM72, and CK-MM in myotubes.
A transient increase in phosphorylation level of Akt was also
observed. However, MENS had no effect on the phosphorylation
level of p42/44 extracellular signal-regulated kinase-1/2 and
5’AMP-activated protein kinase. MENS may increase muscle
protein content accompanied with a transient activation of Akt
and the upregulation of Cav-3 and TRIM72.
The system of zero-pressure gas dynamics conservation laws describes the dynamics of free particles sticking under collision while mass and momentum are conserved. The existence of such solutions was established some time ago. Here we report a uniqueness result that uses the Oleinik entropy condition and a cohesion condition. Both of these conditions are automatically satisfied by solutions obtained in previous existence results. Important tools in the proof of uniqueness are regularizations, generalized characteristics and flow maps. The solutions may contain vacuum states as well as singular measures.