Selective reduction in the nicotinic acetylcholine receptor and dystroglycan at the postsynaptic apparatus of mdx mouse superior cervical ganglion

Our previous data suggested that in mouse sympathetic superior cervical gan glion (SCG) the dystrophin-dystroglycan complex may be involved in the stab ilization of the nicotinic acetylcholine receptor (nAChR) clusters. Here we used SCG of dystrophic mdx mice, which express only the shorter isoforms o f dystrophin (Dys), to investigate whether the lack of the full-length dyst rophin (Dp427) could affect the localization of the dystroglycan and the al pha 3 nAChR subunit (alpha 3AChR) at the postsynaptic apparatus. We found a selective reduction in intraganglionic postsynaptic specializations immuno positive for alpha 3AChR and for alpha- and beta-dystroglycan compared with the wild-type. Moreover, in mdx mice, unlike the wild-type, the disassembl y of intraganglionic synapses induced by postganglionic nerve crush occurre d at the slower rate and was not preceded by the loss of immunoreactivity f or Dys isoforms, beta-dystroglycan, and alpha 3AChR. These data indicate th at the absence of Dp427 at the intraganglionic postsynaptic apparatus of md x mouse SCG interferes with the presence of both dystroglycan and nAChR clu sters at these sites and affects the rate of synapse disassembly induced by postganglionic nerve crush. Moreover, they suggest that the decrease in ga nglionic nAChR may be one of the factors responsible for autonomic imbalanc e described in Duchenne muscular dystrophy patients.