Authors: Stéphanie Wagner Olivier M Dorchies Herrade Stoeckel JeanMarie Warter Philippe Poindron Kenneth Takeda
Publish Date: 2003/08/28
Volume: 447, Issue: 1, Pages: 14-22
Abstract
Under normal conditions in situ muscle fibers and motoneurons the main partners of motor units are strongly dependent on each other This interdependence hinders ex vivo studies of neuromuscular disorders where nervous or muscular components are considered separately To allow in vitro access to complex nerve–muscle relationships we developed a novel nervemuscle coculture system where mouse muscle innervation is assured by rat spinal cord explants The degree of muscular maturation during coculture was evaluated using the distribution of nicotinic acetylcholine receptors AChRs and their electrophysiological characteristics before and after innervation In myotubes from noninnervated cultures AChRs were diffusely distributed over the entire myotube surface Their singlechannel conductance 335±06 pS and mean open time 81±07 ms are characteristic of AChRs described in embryonic or denervated skeletal muscles In innervated muscle fibers from cocultures AChRs appear as discrete aggregates and colocalize with synaptotagmin In addition to the embryonic type currents in innervated fibers AChR currents having high conductance 533±59 pS and short mean open time 26±01 ms characteristic of AChRs at mature neuromuscular junctions were observed Our data support the use of this new nerve–muscle coculture system as a reliable model for the study of murine muscular differentiation and function
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