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Electromagnetic Fields in Biological Systems
(25°C), the SMF exposure induced an increase in NE content in gastrocnemius muscle at
128 mT (+25%) but had no effect at 67 mT (+1%), indicating a stimulatory effect of SMF on
the noradrenergic system activity. However, the SMF did not induce significant increase
in HSP72 levels in gastrocnemius muscles (+29%). The results indicate that noradrenergic systems in gastrocnemius muscles are affected by SMF exposure. Furthermore,
the same research group showed that SMF (128 mT, 1 h/day for 5–15 consecutive days)
effects on glucose and lipid metabolism are time dependent (Lahbib et al. 2010).
Jimena et al. (2009) investigated the effect of an ELF-EMF (60 Hz, 0.7 mT, for 2 hours)
on oxidative damage and skeletal muscle injury prompted by mepivacaine injection
in the anterior tibial muscle of Wistar rats. Results revealed that mepivacaine induces
oxidative stress, EMF prevents the harmful effects induced by mepivacaine, and EMF
facilitates the regeneration process of skeletal muscle. In conclusion, the results showed
the ability of EMFs to modify skeletal muscle response to mepivacaine.
Sakuraba et al. (2005) assessed the potential application and effectiveness of functional magnetic stimulation (FMS) for preventing skeletal muscle atrophy in adult
rats. Functional magnetic stimulation using magnetic stimulator was performed to the
soleus muscle of rats by placing a round magnetic coil on the back of the third to fifth
lumbar vertebral levels (L3–L5) at 1 T and 20 Hz, 60 min/d for ≤10 days. An RT-PCR was
applied to evaluate relative amounts of messenger ribonucleic acid (mRNA) specific to
four myosin heavy chain (MHC) isoforms in soleus muscle during contractile activity by
FMS. Ten-day unloading by hind limb suspension induced a drastic decrease in MHCIβ
and MHCIIa mRNA expressions, although expressions of MHCIIb and MHCIId(x)
mRNA were not decreased. The FMS resuscitated the downregulation of mRNA levels
of MHCIβ and MHCIIa. These results suggest that FMS on acute atrophied muscles is
useful for preventing muscle atrophy.
Raux et al. (2010) examined the hypothesis that modulating supplementary motor
area (SMA) activity using rTMS (5 and 10 Hz) alters primary motor cortex (M1 DIA ) excitability in humans. The amplitude and latency of diaphragm MEPs (MEP DIA ), evoked
through single pulse M1 DIA stimulation before and up to 16 minutes after SMA stimulation, were taken as indicators of M1 DIA excitability. The MEP from the first dorsal interosseous (FDI) muscle (MEP FDI ) served as a control. Four SMA-conditioning sessions
were performed in random order at 1-week intervals. Two aimed at increasing the SMA
activity (5 and 10 Hz, both at 110% of FDI active motor threshold [aMT] and referred to
as 5 Hz and 10 Hz, respectively) and two aimed at decreasing it (1 Hz either at 110% of
FDI aMT or at resting motor threshold [rMT]). The 5 Hz significantly increased MEP DIA
and MEP FDI amplitudes within a maximum of 11–16 minutes poststimulation. The 10 Hz
increased MEP FDI amplitude with a similar time course, but it did not increase MEP DIA
amplitude. Both aMT and rMT failed to decrease MEP DIA and MEP FDI amplitudes. The
MEP DIA and MEP FDI latencies were unaffected by rTMS. These results demonstrate that
5 Hz rTMS over the SMA can increase the excitability of M1 DIA . These observations are
consistent with the hypothesis of a functional connection between SMA and M1 DIA .
3.3.1.8 Skeletal System
Aydin and Bezer (2011) ascertained the effect that an SMF device (22–26 mT) implanted
in rabbit femur had on fracture healing. Results verified that an intramedullary implant
Electromagnetic Fields in Biological Systems
(25°C), the SMF exposure induced an increase in NE content in gastrocnemius muscle at
128 mT (+25%) but had no effect at 67 mT (+1%), indicating a stimulatory effect of SMF on
the noradrenergic system activity. However, the SMF did not induce significant increase
in HSP72 levels in gastrocnemius muscles (+29%). The results indicate that noradrenergic systems in gastrocnemius muscles are affected by SMF exposure. Furthermore,
the same research group showed that SMF (128 mT, 1 h/day for 5–15 consecutive days)
effects on glucose and lipid metabolism are time dependent (Lahbib et al. 2010).
Jimena et al. (2009) investigated the effect of an ELF-EMF (60 Hz, 0.7 mT, for 2 hours)
on oxidative damage and skeletal muscle injury prompted by mepivacaine injection
in the anterior tibial muscle of Wistar rats. Results revealed that mepivacaine induces
oxidative stress, EMF prevents the harmful effects induced by mepivacaine, and EMF
facilitates the regeneration process of skeletal muscle. In conclusion, the results showed
the ability of EMFs to modify skeletal muscle response to mepivacaine.
Sakuraba et al. (2005) assessed the potential application and effectiveness of functional magnetic stimulation (FMS) for preventing skeletal muscle atrophy in adult
rats. Functional magnetic stimulation using magnetic stimulator was performed to the
soleus muscle of rats by placing a round magnetic coil on the back of the third to fifth
lumbar vertebral levels (L3–L5) at 1 T and 20 Hz, 60 min/d for ≤10 days. An RT-PCR was
applied to evaluate relative amounts of messenger ribonucleic acid (mRNA) specific to
four myosin heavy chain (MHC) isoforms in soleus muscle during contractile activity by
FMS. Ten-day unloading by hind limb suspension induced a drastic decrease in MHCIβ
and MHCIIa mRNA expressions, although expressions of MHCIIb and MHCIId(x)
mRNA were not decreased. The FMS resuscitated the downregulation of mRNA levels
of MHCIβ and MHCIIa. These results suggest that FMS on acute atrophied muscles is
useful for preventing muscle atrophy.
Raux et al. (2010) examined the hypothesis that modulating supplementary motor
area (SMA) activity using rTMS (5 and 10 Hz) alters primary motor cortex (M1 DIA ) excitability in humans. The amplitude and latency of diaphragm MEPs (MEP DIA ), evoked
through single pulse M1 DIA stimulation before and up to 16 minutes after SMA stimulation, were taken as indicators of M1 DIA excitability. The MEP from the first dorsal interosseous (FDI) muscle (MEP FDI ) served as a control. Four SMA-conditioning sessions
were performed in random order at 1-week intervals. Two aimed at increasing the SMA
activity (5 and 10 Hz, both at 110% of FDI active motor threshold [aMT] and referred to
as 5 Hz and 10 Hz, respectively) and two aimed at decreasing it (1 Hz either at 110% of
FDI aMT or at resting motor threshold [rMT]). The 5 Hz significantly increased MEP DIA
and MEP FDI amplitudes within a maximum of 11–16 minutes poststimulation. The 10 Hz
increased MEP FDI amplitude with a similar time course, but it did not increase MEP DIA
amplitude. Both aMT and rMT failed to decrease MEP DIA and MEP FDI amplitudes. The
MEP DIA and MEP FDI latencies were unaffected by rTMS. These results demonstrate that
5 Hz rTMS over the SMA can increase the excitability of M1 DIA . These observations are
consistent with the hypothesis of a functional connection between SMA and M1 DIA .
3.3.1.8 Skeletal System
Aydin and Bezer (2011) ascertained the effect that an SMF device (22–26 mT) implanted
in rabbit femur had on fracture healing. Results verified that an intramedullary implant