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Differential growth behavior of sensory neurons during innervation of dermis and epidermis. An in vitro time-lapse analysis
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Differential growth behavior of sensory neurons during innervation of dermis and epidermis. An in vitro time-lapse analysis. VERNA, J.M.; SAXOD, R. - ERA CNRS 621, Laboratoire de Zoologie et Biologie animale, B.P. 68, 38402 Saint-Martin-d'H~res Cedex, France. Serum-free co-cultures, consisting of h~nbar spinal ganglia and either dermal or epidermal explants from 7-day chick embryos, have been used to study the morphogenetic mechanisms involved in the establisNnent of cutaneous innervation. Preliminary results obtained from morphometric time-lapse analysis of the cultures demonstrate that nerve fibers behave differently when interacting with dermis or epidermis : I. When growing neurites meet migrating mesenchymal cells at the periphery of dermal explants, no change occurs in the general orientation of growth and transient contacts are formed between growth cones and dermal cells. 2. On the contrary, in the presence of epidermis, most nerve fibers (about 60%) change their orientation when arriving in the vicinity of epidermal cells and, at a mean distance of 40 p~n deviate around the explant. The growth cones of the rest of the fibers (about 40%) contact the epidermal cells but less than 10% end up inside the explant. It is the first time that such a "long range avoidance" is reported for nerve fibers.
"Longitudinal zonal differentiation during corticogenesis in Macaca mulatta" Voogd, J. and IKappel, R.M., Dpt. of Anatomy, University of Leiden, 2333 AL, The Netherlands and iDpt. of Anatomy, University of Suriname, Paramaribo, Suriname. Longitudinal zonal differentiation was studied in the period preceding the appearance of transverse fissures (48 - 80 days post conception). The material belongs to the collection of the Dpt. of Anatomy, R.C. University of Nijmegen, the Netherlands (Dr. A.A.M. Gribnau). Between 50 and 70 days a pattern of longitudinal zones, based on regional aggregation of future Purkinje cells, into five main clusters (I, II, II],"X", IV) can be recognized. The "X" cluster was named after a similar cluster in rat embryos described by Korneliussen (J. Hirnforsch. I0: 379'68). Initially I, III and IV are located superficial to the deep and interconnected clusters II and X. In older fetuses II and X come to the surface in between the superficial clusters and the connection between them dissolves. Each cluster is related to a particular central cerebellar nucleus. The topography and the nuclear relations of the clusters allow their identification with longitudinal zones of the adult~ The pattern disappears around day 80, when the rearrangement of the Purkinje cells into a continuous monolayer has begun. 2Voogd and Bigar~, Topographical distribution of olivary and corticonuclear fibers in the cerebellum. A review. In: The inferior olivary nucleus. Raven Press,1980 pp. 207-234.
Evidence for the migration of principal and giant neurons into the developing dorsal cochlear nucleus of the North American opossum. Willard, F.H.; Thompson, D.M. and Martin, G.F. Department of Anatomy, The Ohio State University, Columbus, Ohio 43210. The dorsal cochlear nucleus(DCN) consists of several cytologically distinct layers. Postioned within these layers are two types of large multipolar neurons: principal cells and giant cells. The former have a pronounced vertical orientation with their cell bodies aligned in layer II. The large multipolar neurons are the sole source of DCN projections to the inferior colliculus(IC;Willard and Martin,1983). We have taken advantage of this fact and the early birth of the opossum to study the location of DCN large multipolar neurons (and their precursors) that innervate the IC, at different developmental stages. An age-graded series of pouch-young opossums received IC placements of horseradish peroxidase(HRP). At stages 27mm and 35m~n(snout-rump length,SRL) an elongated band of HRP-containing neurons was present in the dorsal acoustic stria. By 45mm(SRL) most of these HRP-labelled neurons were contained within the DCN, but no orientation of cells was evident. ~he alignment of principal cell somata in layer II occurred during the 50-60mm(SRL) stages. Our results suggest that the principal and giant cells gain access to the DCN by migrating over the dorsal acoustic stria. During this process it is evident that these migrating neurons have already established contact with the contralateral IC by virtue of their retrograde transport of HRP. Supported by grants 1 F 32 NS-6829-01 (FHW) and NS 07410 and BNS-8008635 (GFM).
Differential growth behavior of sensory neurons during innervation of dermis and epidermis. An in vitro time-lapse analysis. VERNA, J.M.; SAXOD, R. - ERA CNRS 621, Laboratoire de Zoologie et Biologie animale, B.P. 68, 38402 Saint-Martin-d'H~res Cedex, France. Serum-free co-cultures, consisting of h~nbar spinal ganglia and either dermal or epidermal explants from 7-day chick embryos, have been used to study the morphogenetic mechanisms involved in the establisNnent of cutaneous innervation. Preliminary results obtained from morphometric time-lapse analysis of the cultures demonstrate that nerve fibers behave differently when interacting with dermis or epidermis : I. When growing neurites meet migrating mesenchymal cells at the periphery of dermal explants, no change occurs in the general orientation of growth and transient contacts are formed between growth cones and dermal cells. 2. On the contrary, in the presence of epidermis, most nerve fibers (about 60%) change their orientation when arriving in the vicinity of epidermal cells and, at a mean distance of 40 p~n deviate around the explant. The growth cones of the rest of the fibers (about 40%) contact the epidermal cells but less than 10% end up inside the explant. It is the first time that such a "long range avoidance" is reported for nerve fibers.
"Longitudinal zonal differentiation during corticogenesis in Macaca mulatta" Voogd, J. and IKappel, R.M., Dpt. of Anatomy, University of Leiden, 2333 AL, The Netherlands and iDpt. of Anatomy, University of Suriname, Paramaribo, Suriname. Longitudinal zonal differentiation was studied in the period preceding the appearance of transverse fissures (48 - 80 days post conception). The material belongs to the collection of the Dpt. of Anatomy, R.C. University of Nijmegen, the Netherlands (Dr. A.A.M. Gribnau). Between 50 and 70 days a pattern of longitudinal zones, based on regional aggregation of future Purkinje cells, into five main clusters (I, II, II],"X", IV) can be recognized. The "X" cluster was named after a similar cluster in rat embryos described by Korneliussen (J. Hirnforsch. I0: 379'68). Initially I, III and IV are located superficial to the deep and interconnected clusters II and X. In older fetuses II and X come to the surface in between the superficial clusters and the connection between them dissolves. Each cluster is related to a particular central cerebellar nucleus. The topography and the nuclear relations of the clusters allow their identification with longitudinal zones of the adult~ The pattern disappears around day 80, when the rearrangement of the Purkinje cells into a continuous monolayer has begun. 2Voogd and Bigar~, Topographical distribution of olivary and corticonuclear fibers in the cerebellum. A review. In: The inferior olivary nucleus. Raven Press,1980 pp. 207-234.
Evidence for the migration of principal and giant neurons into the developing dorsal cochlear nucleus of the North American opossum. Willard, F.H.; Thompson, D.M. and Martin, G.F. Department of Anatomy, The Ohio State University, Columbus, Ohio 43210. The dorsal cochlear nucleus(DCN) consists of several cytologically distinct layers. Postioned within these layers are two types of large multipolar neurons: principal cells and giant cells. The former have a pronounced vertical orientation with their cell bodies aligned in layer II. The large multipolar neurons are the sole source of DCN projections to the inferior colliculus(IC;Willard and Martin,1983). We have taken advantage of this fact and the early birth of the opossum to study the location of DCN large multipolar neurons (and their precursors) that innervate the IC, at different developmental stages. An age-graded series of pouch-young opossums received IC placements of horseradish peroxidase(HRP). At stages 27mm and 35m~n(snout-rump length,SRL) an elongated band of HRP-containing neurons was present in the dorsal acoustic stria. By 45mm(SRL) most of these HRP-labelled neurons were contained within the DCN, but no orientation of cells was evident. ~he alignment of principal cell somata in layer II occurred during the 50-60mm(SRL) stages. Our results suggest that the principal and giant cells gain access to the DCN by migrating over the dorsal acoustic stria. During this process it is evident that these migrating neurons have already established contact with the contralateral IC by virtue of their retrograde transport of HRP. Supported by grants 1 F 32 NS-6829-01 (FHW) and NS 07410 and BNS-8008635 (GFM).