ABSTRACT Introduction: Before the nerve contacts the skeletal muscle, the nicotinic acetylcholine receptors (nAChRs) form aggregates known as prepatterned clusters. We investigated their role in the occurrence of Ca2+ spikes and twitching during myogenesis. Methods: Cultured mouse myotubes were used as cell models. Cells were subjected to a combination of immunostaining, Ca2+ imaging and electrophysiological analysis. Results: A single prepatterned nAChR cluster per myotube was generally detected. A correlation between formation of the prepatterned clusters and occurrence of Ca2+ spikes and twitching was observed. Increase in size of the prepatterned clusters raised the frequency of Ca2+ spikes and twitching. Blockade of the electrical activity triggered by the autocrine activation of prepatterned nAChR induced over-numbered nAChR clusters. Conclusions: Prepatterned nAChR aggregation is required for Ca2+ spikes and twitching of developing myotubes. Moreover, prepatterned nAChR-driven electrical activity preserves the distribution of nAChRs, mimicking the effect of synaptic activity before innervation. Muscle Nerve 46: 112–121, 2012

Novel role for prepatterned nicotinic acetylcholine receptors during myogenesis

FORMAGGIO, Elena;FUMAGALLI, Guido Francesco;
2012

Abstract

ABSTRACT Introduction: Before the nerve contacts the skeletal muscle, the nicotinic acetylcholine receptors (nAChRs) form aggregates known as prepatterned clusters. We investigated their role in the occurrence of Ca2+ spikes and twitching during myogenesis. Methods: Cultured mouse myotubes were used as cell models. Cells were subjected to a combination of immunostaining, Ca2+ imaging and electrophysiological analysis. Results: A single prepatterned nAChR cluster per myotube was generally detected. A correlation between formation of the prepatterned clusters and occurrence of Ca2+ spikes and twitching was observed. Increase in size of the prepatterned clusters raised the frequency of Ca2+ spikes and twitching. Blockade of the electrical activity triggered by the autocrine activation of prepatterned nAChR induced over-numbered nAChR clusters. Conclusions: Prepatterned nAChR aggregation is required for Ca2+ spikes and twitching of developing myotubes. Moreover, prepatterned nAChR-driven electrical activity preserves the distribution of nAChRs, mimicking the effect of synaptic activity before innervation. Muscle Nerve 46: 112–121, 2012
myogenesis; nicotinic acetylcholine receptors; skeletal muscle; agrin
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11562/538949
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