Delayed synapse elimination in mouse levator palpebrae superioris muscle
- 16 June 2011
- journal article
- research article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 519 (15), 2907-2921
- https://doi.org/10.1002/cne.22700
Abstract
At birth, synaptic sites in developing rodent muscles are innervated by numerous motor axons. During subsequent weeks, this multiple innervation disappears as one terminal strengthens, and all the others are eliminated. Experimental perturbations that alter neuromuscular activity affect the rate of synaptic refinement, with more activity accelerating the time to single innervation and neuromuscular blockade retarding it. However, it remains unclear whether patterns of muscle use (driven by endogenous neuronal activity) contribute to the rate of synapse elimination. For this reason we examined the timing of supernumerary nerve terminal elimination at synapses in extraocular muscles (EOMs), a specialized set of muscles controlling eye movements. On the basis of their exceptionally high patterns of activity, we hypothesized that synaptic refinement would be greatly accelerated at these synapses. We found, however, that rates of synaptic refinement were only modestly accelerated in rectus and oblique EOMs compared with synapses in somite‐derived skeletal muscle. In contrast to these results, we observed a dramatic delay in the elimination of supernumerary nerve terminals from synapses in the levator palpebrae superioris (LPS) muscle, a specialized EOM that initiates and maintains eyelid elevation. In mice, natural eye opening occurs at the end of the second postnatal week of development. Thus, although synapse elimination is occurring in most EOMs and somite‐derived skeletal muscles, it appears to be dramatically delayed in a set of specialized eyelid muscles that remain immobile during early postnatal development. J. Comp. Neurol. 519:2907–2921, 2011.Keywords
This publication has 65 references indexed in Scilit:
- Postnatal development enhances the effects of cholinergic inputs on recruitment threshold and firing rate of rat oculomotor nucleus motoneuronsNeuroscience, 2010
- To build a synapse: signaling pathways in neuromuscular junction assemblyDevelopment, 2010
- Collagen XIX is expressed by interneurons and contributes to the formation of hippocampal synapsesJournal of Comparative Neurology, 2009
- Polyneuronal Innervation of Single Muscle Fibers in Cat Eye Muscle: Inferior ObliqueJournal of Neurophysiology, 2009
- Comprehensive expression profiling by muscle tissue class and identification of the molecular niche of extraocular muscleThe FASEB Journal, 2003
- Induction, assembly, maturation and maintenance of a postsynaptic apparatusNature Reviews Neuroscience, 2001
- DEVELOPMENT OF THE VERTEBRATE NEUROMUSCULAR JUNCTIONAnnual Review of Neuroscience, 1999
- Gradual loss of synaptic cartels precedes axon withdrawal at developing neuromuscular junctionsNeuron, 1993
- Structure of developing frog neuromuscular junctionsJournal of Neurocytology, 1980
- Regional differences in the timing of synapse elimination in skeletal muscles of the neonatal rabbitBrain Research, 1979