INNERVATION OF THE UNDIFFERENTIATED LIMB BUD IN RABBIT EMBRYO

  • 1 January 1982
    • journal article
    • research article
    • Vol. 134  (JUN) , 795-808
Abstract
The concept that there are no nerves in the limb bud ot mammalian embryos prior to differentiation was reexamined. Rabbit embryos were collected at 260 and 290 h gestation, prior to cartilage formation in the forelimb (320 h). Forelimb buds and adjacent neural tube were excised, fixed and embedded for light microscopy and EM. The limb buds were sectioned in 2 planes by serial 1-.mu.m sections and inspected by light microscopy. Bundles of nerve fibers were seen within the proximal 3rd of the limb bud, with distal ramification into adjacent zones of condensing mesenchyme. EM confirmed the presence of axons and associated immature Schwann cells. The existence of an anatomical framework through which a neurotrophic influence might be brought to bear upon mesenchyme prior to early differentiation is demonstrated.