Schwann Cells/cytology; Sciatic Nerve/embryology; Stem Cells/cytology; Animals; Apoptosis/drug effects; Autocrine Communication; Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinases/metabolism; Cell Differentiation/drug effects; Cell Division/drug effects; Cell Lineage/drug effects; Cell Separation; Cell Survival/drug effects; Cells, Cultured; DNA/biosynthesis; Embryo, Mammalian/cytology; Embryo, Mammalian/innervation; Fibroblast Growth Factor 2/pharmacology; Glycoproteins/pharmacology; Growth Substances/analysis; Hindlimb/embryology; Hindlimb/innervation; Mice; Neuregulins; Phosphatidylinositol 3-Kinases/metabolism; Phosphoinositide-3 Kinase Inhibitors; Schwann Cells/drug effects; Sciatic Nerve/cytology; Stem Cells/drug effects