Reutilization of trigeminal motoneurons during amphibian metamorphosis

Indirect evidence suggests that trigeminal motoneurons (Vmns) in Rana pipie ns innervate distinct myofiber populations in tadpoles and adult frogs. Red eployment occurs when the larval myofibers die and are replaced during meta morphosis. To directly test this hypothesis, DiI was injected into the larv al muscle and Fast Blue into the replacement myofiber population Over 95% o f the Vmns contained both tracers, providing support for the innervation of sequential targets by the same motoneurons. (C) 1998 Elsevier Science B.V. All rights reserved.