[Effects of monolateral ablations of the presumptive limb buds on the early developmental phases of the central and peripheral nervous system].
The size of the spinal ganglia, as well as of the posterior and lateral funiculi of the spinal cord, at the cervical, thoracic, lumbar and sacral levels, was carefully evaluated, on both sides, by measuring their surfaces on each transverse histological section from chick embryos submitted, at the second-second and a half day, to ablations of the right presumptive limb buds, and fixed at the 9th - 13th day. On the extirpation side, the ganglion and posterior funiculus size always resulted significantly smaller, the average degree of reduction being nearly the same at the levels of the brachial and the lumbo-sacral plexuses (-50-60% for the ganglia, -25-30% for the posterior funiculus). However, within the same group of metameres (e.g., the corresponding to the brachial plexus), the analysis carried out metamere by metamere showed that the reduction degree was not homogeneous, owing probably to a) the extent of the different peripheral fields supplied by the various metameres, b) the degree of the regulative processes occurred after the ablations, and/or c) the extent of the extirpated regions. The size reduction of the posterior funiculus, observed also in the neuromeres immediately cranial to those related to the plexuses, could depend upon its peculiar composition, relatively short intersegmental tracts representing the majority of its fibers. No significant reduction was remarked for the lateral funiculus size.
D000818:Animals; D002490:Central Nervous System / Q000196:embryology; D002642:Chick Embryo; D005121:Extremities / Q000196:embryology*; D005727:Ganglia, Spinal / Q000196:embryology*; D010525:Peripheral Nerves / Q000196:embryology
Effetti della ablazione monolaterale dei territóri presuntivi degli arti sulle fasi precoci dello sviluppo del SNC e del SNP.