Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2004 Sep 24;5(1):33.
doi: 10.1186/1471-2474-5-33.

Magnesium administration provokes motor unit survival, after sciatic nerve injury in neonatal rats

N Gougoulias  1 , A Hatzisotiriou, D Kapoukranidou, M Albani
Affiliations

Magnesium administration provokes motor unit survival, after sciatic nerve injury in neonatal rats

N Gougoulias et al. BMC Musculoskelet Disord. .

Abstract

Background: We examined the time course of the functional alterations in two types of muscles following sciatic nerve crush in neonatal rats and the neuroprotective effect of Mg2+.

Methods: The nerve crush was performed on the 2nd postnatal day. MgSO4*7H2O was administered daily for two weeks. Animals were examined for the contractile properties and for the number of motor units of extensor digitorum longus and soleus muscles at three postnatal stages and adulthood. Four experimental groups were included in this study: i) controls, ii) axotomized rats, iii) magnesium treated controls and iv) axotomized and Mg2+-treated rats.

Results: Axotomy resulted in 20% MU survival in EDL and 50% in soleus. In contrast, magnesium treatment resulted in a significant motor unit survival (40% survival in EDL and 80% in soleus). The neuroprotective effects of Mg2+ were evident immediately after the Mg2+-treatment. Immature EDL and soleus muscles were slow and fatigueable. Soleus gradually became fatigue resistant, whereas, after axotomy, soleus remained fatigueable up to adulthood. EDL gradually became fastcontracting. Tetanic contraction in axotomized EDL was just 3,3% of the control side, compared to 15,2% in Mg2+-treated adult rats. The same parameter for axotomized soleus was 12% compared to 97% in Mg2+-treated adult rats.

Conclusions: These results demonstrate that motoneuron death occurs mostly within two weeks of axotomy. Magnesium administration rescues motoneurons and increases the number of motor units surviving into adulthood. Fast and slow muscles respond differently to axotomy and to subsequent Mg2+ treatment in vivo.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Time course of changes in the number of motor units of EDL and soleus muscles in the left hindlimb. The number of motor units in the right (control) hindlimb is set 40 in the EDL and 30 in the soleus.
Figure 2
Figure 2
Representative Isometric Tension and Fatigue Recordings of EDL and Soleus in adult rats
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Buller AJ, Eccles JC and Eccles EM. Interactions between motoneurons and muscles in respect of the characteristic speeds of their responses. J Physiol. 1960;150:417–439. - PMC - PubMed
    1. Vrbova G, Gordon T, Jones R. Neve Muscle interaction. 2. Chapman and Hall; 1995.
    1. Rothman SM, Olney JW. Excitotoxicity and the NMDA receptor. TINS. 1987;10:299–302. doi: 10.1016/0166-2236(87)90177-9. - DOI - PubMed
    1. Lodge D, Johnson KM. Noncompetitive excitatory amino acid receptor antagonists. TIPS. 1990;11:81–86. doi: 10.1016/0165-6147(90)90323-Z. - DOI - PubMed
    1. Lawson SJ, Lowrie MB. The role of apoptosis and excitotoxicity in the death of spinal motoneurons and interneurons after neonatal nerve injury. Neuroscience. 1998;87:337–48. doi: 10.1016/S0306-4522(98)00120-1. - DOI - PubMed

MeSH terms