COCULTURE OF RAT EMBRYONIC PROPRIOCEPTIVE SENSORY NEURONS AND MYOTUBES

With the aim to study the cellular mechanisms underlying the process o f muscle spindle (re)generation, dorsal root ganglia (DRG) neurons der ived from 16-day rat embryos were cocultured with developing myotubes in a compartmentalized culture device. To accomplish the selective sur vival and neurite formation of the proprioceptive subpopulation, the n eurotrophic factor, neurotrophin-3, was added to the culture medium. I t appeared that the proprioceptive DRG neurons could develop specializ ed, la afferent terminallike contacts with myotubes. However, these in teractions were scarce and did not result in the induction of differen tiation of the contacted myotubes into intrafusal fibers as normally o ccurs during in vivo development. The present coculture setup apparent ly lacks appropriate regulatory factors essential for the proper match ing of sensory axons and intrafusal fiber precursors and the induction of a functional sensory myoneural connection. (C) 1996 John Wiley & S ons, Inc.