Mesenchyme of embryonic reproductive ducts directs process outgrowth of Retzius neurons in the medicinal leech.
Research article published in Developmental biology (1992)
Abstract
In the two segments of the medicinal leech (Hirudo medicinalis) that contain the male (segment 5) and the female (segment 6) reproductive ducts, the paired Retzius (Rz) neurons are distinguished by several unique properties. For example, the muscles and glands of the body wall are the primary peripheral targets of Rz neurons in standard segments [Rz(X)], whereas the muscles and glands of the reproductive ducts are the primary peripheral targets of Rz neurons in the two reproductive segments [Rz(5,6)]. In this paper, we show that organogenesis and differentiation, which generate an epithelial tube surrounded by mesenchymal cells, occur in the embryonic reproductive ducts at approximately the time when Rz processes first contact these structures. The growth cones leading one branch of the posterior axon of Rz(5,6) contact the duct mesenchymal cells. Following initiation of this contact, these posterior growth cones enlarge and send out numerous filopodia. Secondarily, growth cones leading the anterior axon of each Rz(5,6) also modify their shapes and trajectories. When embryonic reproductive ducts were transplanted into posterior (nonreproductive) segments, the branch of the posterior Rz axon near the ectopic reproductive tissue produced enlarged growth cones and extended several secondary branches into the mesenchyme of the ectopic tissue. This result suggests that the reproductive mesenchyme is attractive to, and can modify the growth of, all Rz neurons. The behavior of Rz(5,6) growth cones suggests that the reproductive mesenchyme cells provide guidance cues that control the location in which Rz axons elaborate their peripheral arborization and form synapses, and that the mesenchyme may also stimulate the production of a densely branched arbor.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Mesenchyme of embryonic reproductive ducts directs process outgrowth of Retzius neurons in the medicinal leech.
Por qué esto importa para la hirudoterapia
This study examined how the mesenchyme of embryonic reproductive ducts in the medicinal leech (Hirudo medicinalis) directs process outgrowth of Retzius neurons in segments 5 and 6, showing that transplanted reproductive duct mesenchyme attracted Retzius axon growth cones and induced densely branched arbors in non-reproductive segments. The findings suggest reproductive mesenchyme cells provide guidance cues controlling where Retzius axons elaborate peripheral arborization and form synapses. For ASH's domain, this article is directly about the medicinal leech, the primary species used in hirudotherapy, and contributes to basic neurodevelopmental biology of Hirudo medicinalis. However, it has no direct therapeutic or secretome relevance — it is a pure neuroscience/developmental biology study of neuronal pathfinding, with no implications for leech therapy practice, salivary compounds, or clinical applications.
Citación
Mesenchyme of embryonic reproductive ducts directs process outgrowth of Retzius neurons in the medicinal leech.
French et al. · Developmental biology, 1992
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Añadido a la biblioteca ASH: May 28, 2026 · Última actualización del sitio: June 18, 2026