PT  - JOURNAL ARTICLE
AU  - Rufeng Xu
AU  - Miriam M. Salpeter
TI  - Acetylcholine Receptors in Innervated Muscles of Dystrophic<em>mdx</em> Mice Degrade as after Denervation
AID  - 10.1523/JNEUROSCI.17-21-08194.1997
DP  - 1997 Nov 01
TA  - The Journal of Neuroscience
PG  - 8194--8200
VI  - 17
IP  - 21
4099  - http://www.jneurosci.org/content/17/21/8194.short
4100  - http://www.jneurosci.org/content/17/21/8194.full
SO  - J. Neurosci.1997 Nov 01; 17
AB  - Acetylcholine receptors (AChRs) are present at the top of the postsynaptic membrane of the neuromuscular junction (NMJ) at very high density, possibly anchored to cytoskeletal elements. The present study investigated whether AChR degradation is affected in animals lacking dystrophin, a protein that is an integral part of the cytoskeletal complex and is missing in Duchenne muscular dystrophy. The animal model for Duchenne muscular dystrophy, the mutant mdx mouse, was used to determine whether disruption of the cytoskeleton, caused by the absence of dystrophin, affects AChR degradation. Of the two populations of junctional AChRs, Rs (expressed in innervated adult muscles) and Rr (expressed in embryonic or denervated muscles), only Rs are affected in mdx animals. In innervatedmdx soleus, diaphragm, and sternomastoid muscles, the AChRs have an accelerated degradation rate (t1/2 of ∼3–5 d), similar to that acquired by Rs in control muscles after denervation. The Rs inmdx NMJs do not accelerate further when the muscles are denervated. The absence of dystrophin does not affect the degradation rate of the Rr AChRs (t1/2 of 1 d), which are expressed after denervation in mdx as in control muscles. These results suggest that dystrophin or an intact cytoskeletal complex may be required for neuronal stabilization of Rs receptors at the adult neuromuscular junctions.