title: Blastomere ablation and the developmental origin of identified monoamine-containing neurons in the leech.
abstract: Ablation of different identifiable blastomeres of the early embryo of the leech Helobdella triserialis was found to lead to the absence of different sets of segmentally iterated monoamine-containing neurons in subsequent development. Thus the ablation of one of the paired N ectoteloblasts leads to the absence of one member of each of the three bilateral pairs of serotonin-containing neurons (one of which is the Retzius cell) from each segmental ganglion. The ablation of one of the paired OP blastomeres (precursors of the paired O and P ectoteloblasts) leads to the absence of one member of each of the two bilateral pairs of lateral dopamine-containing neurons that lie in the body wall of each segment. And the ablation of one of the paired Q ectoteloblast leads to the absence of one member of the bilateral pair of medial dopamine-containing neurons that lie in the body wall of each segment. These results suggest that each of these sets of monoamine-containing neurons is derived from a particular blastomere. Upon ablation of that blastomere the set does not develop from any other source.
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D007865:Leeches / Q000196:embryology* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D012701:Serotonin; D004298:Dopamine