Myogenic cells in the rat embryonic brain stem

The principal finding of this study is the establishment of culture conditions that permit the survival of a very limited population of muscle precursor cells from the embryonic and neonatal rat brain stem, with these cells displaying the capacity to differentiate into contractile striated fibers under these in vitro conditions. Examination of desmin and troponin T expression by immunoperoxidase analysis revealed the presence of the two muscle proteins in the mononucleated precursors and in differentiated multinucleated myotubes. In vivo, examination of sections at corresponding stages revealed the simultaneous presence of troponin T, desmin, and lectin binding sites--a property of endothelial cells--association which appears to be transitory, since it is no longer detectable in the adult brain. The presence of the choroid plexus neuroepithelium, in close vicinity with TnT+, desmin+cells located in a limited zone of the brain stem, as well as the stage of expression for these markers suggest an interaction between brain myogenic cells and the onset of the embryonic circulation. The question of the embryological origin of the brain myogenic cells is discussed.