J Korean Orthop Assoc.  2002 Aug;37(4):559-566.

Effect of Intermittent Electrical Stimulation of Sciatic Nerve on Expression of Neuronal Nitric Oxide Synthase (nNOS) Protein in the Soleus and Medial Gastrocnemius Muscles following Hindlimb Suspension in Rats

Affiliations
  • 1Department of Orthopaedic Surgery, Daerim St. Mary's Hospital, Seoul, Korea. Kim21416@korea.com
  • 2Department of Physiology, School of Medicine, Wonkwang University, Iksan, Korea.

Abstract

PURPOSE: The present study was designed to evaluate the effect of intermittent electrical stimulation (ES) of the sciatic nerve on the expression of neuronal nitric oxide synthase (nNOS) protein in the soleus and in the medial gastrocnemius muscles 2 weeks following hindlimb suspension (HS).
MATERIALS AND METHODS
In the HS+ES group, a pair of stainless steel electrodes were placed at the midportion of the unilateral sciatic nerve during hindlimb unloading. Square wave pluses with a 5 seconds ON-OFF pattern were applied to the sciatic nerve 4 hours a day for 14 days. The electrical stimulation parameters were 20 Hz, 0.3 ms, 1-5 voltage. 14 days later the sciatic nerve stimulation maximal twitch response was measured in the soleus and medial gastrocnemius muscles using an isometric tension transducer and polygraph. Western blot was used to analyze the expression of nitric oxide synthase (nNOS) protein in hindlimb muscles.
RESULTS
The soleus muscle consisted of slow-twitch muscle fiber and showed a prominent decrease in maximum twitch tension and muscle weight than the medial gastrocnemius muscle 2 weeks after hindlimbs suspension. Hindlimbs suspension caused a reduction in the relative quantity of nNOS protein by 89% and 55% in the soleus and the medial gastrocnemius muscles, respectively, after 2 weeks of unloading compared with the ambulatory controls. However, intermittent electrical stimulation of the sciatic nerve delayed reduction significantly with respect to the expression of nNOS protein and twitch tension during hindlimb unloading.
CONCLUSION
The results suggest that application of electrical stimulation to the sciatic nerve has a significant effect on NO signal transduction by regulating nNOS expression in atrophied hindlimb extensor muscles.

Keyword

Soleus muscle; Medial gastrocnemius muscle; Muscle atrophy; Electrical stimulation of sciatic nerve (ES); Neuronal nitric oxide synthase (nNOS) protein; NO

MeSH Terms

Animals
Blotting, Western
Electric Stimulation*
Electrodes
Hindlimb Suspension*
Hindlimb*
Muscle Fibers, Slow-Twitch
Muscle, Skeletal
Muscles*
Muscular Atrophy
Neurons*
Nitric Oxide Synthase
Nitric Oxide Synthase Type I*
Rats*
Sciatic Nerve*
Signal Transduction
Stainless Steel
Transducers
Nitric Oxide Synthase
Nitric Oxide Synthase Type I
Stainless Steel
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