Browsing by Subject "Reptiles"
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- PublicationOpen AccessEstructura del mesencéfalo y diencéfalo en aves y reptiles: aportaciones a una síntesis en la búsqueda de homología(Universidad de Murcia, 2011-09-29) Martínez de la Torre y Fox, Margarita; Puelles López, Luis; Departamentos y Servicios::Departamentos de la UMU::Anatomía Humana y PsicobiologíaEl trabajo consiste en un estudio comparado de la estructura del mesencéfalo y diencéfalo en el pollo y diversos reptiles (tortuga, lagartos, serpiente), dentro del marco conceptual del modelo segmentario (neuromérico) de Puelles et al. (1987). Se utiliza como material preparaciones en diversos planos de corte teñidas con cresil violeta (citoarquitectura) o sometidas a la reacción histoquímica de Karnovski para la acetilcolinesterasa (neuropilos y ciertos grupos neuronales). Se identifican las fronteras interneuroméricas respectivas del mesencéfalo, pretecho y las partes dorsal y ventral del tálamo (tálamo y pretálamo según Puelles y Rubenstein, 2003), así como las subregiones nucleares y núcleos individuales homólogos por identidad de su posición topológica dentro del modelo y parecido citoarquitectónico e histoquímico. En la discusión se alude a los datos existentes sobre conectividad, apoyando las nociones de homología esbozadas previamente, y se aborda asimismo de modo preliminar las posibles homologías con el diencéfalo de los mamíferos. This work represents a comparative study of mesencephalic and diencephalic structure in the chick and several reptiles (turtle, lizards, snake), performed within the framework of the segmental (neuromeric) model of Puelles et al. (1987). The material consisted of sets of sections in different planes stained with cresyl violet (cytoarchitecture) or reacted histochemically for acetylcholinesterase according to Karnovski’s procedure (neuropiles and some neuronal groups). The respective interneuromeric boundaries of the pretectum and the classic dorsal and ventral thalami were identified (thalamus and prethalamus of Puelles and Rubenstein, 2003), as well as nuclear regions and individual nuclei held to be homologous according to identical topological positions within the model and cytoarchitectonic or histochemical similarity. The Discussion reviews existing connectivity data supporting the deduced conclusions on homology, and examines tentatively possible homologies wi th the mammalian diencephalon.
- PublicationOpen AccessLesion and regeneration in the medical cerebral cortex of lizards(Murcia : F. Hernández, 1992) López-García, Carlos; Molowny, A.; Martínez Guijarro, F.J.; Blasco-lbáñez, J.M.; Luis de la Iglesia, J.A.; Bernabeu, A.; García-Verdugo, J.M.The cerebral cortex of Squamate reptiles (lizards and snakes) may be regarded as an archicortex or ereptilian hippocampus». In lizards, one cortical area, the media1 cortex, may be considered as a true ~fascia dentata» on grounds of its anatomy, connectivity and cyto- chemo-architectonics of its main zinc-rich axonal projection. Moreover, its late ontogenesis and postnatal development support this view. In normal conditions, it shows delayed postnatal neurogenesis and growth during the lizard's life span. Remnant neuroblasts in the media1 cortical ependyma of adult lizards seasonally proliferate. The late-produced immature neurocytes migrate to the medial cortex cell layer where they differentiate and give off zinc-containing axons directed to the rest of cortical areas. This results in a continuous growth of the medial cortex and its zinc-rich axonal projection. Perhaps the most important characteristic of the lizard medial cortex is that it can regenerate after having been almost completely destroyed. Recent experiments in our laboratory have shown that chemical lesion of its neurons (up to 95%) results in a cascade of events; first, those related with massive neuronal death and axonal-dendritic retraction and, secondly, those related with a triggered neuroblast proliferation and subsequent neohistogenesis, and the regeneration of an almost new medial cortex that shows itself undistinguishable from a normal undamaged one. This is the only report to our knowledge that an arnniote central nervous centre may regenerate by new neuron production and neo-histogenesis. Perhaps the media1 cortex of lizards may be used as a model for neuronal regeneration andlor transplant experiments in mammals or even in primates.
- PublicationOpen AccessNo rapid and demarcating astroglial reaction to stab wounds in Agama and Gecko lizards and the caiman Paleosuchus - it is confined to birds and mammals(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Lőrincz, Dávid; Kálmán, Mihályy. The present study proves that the rapid and demarcating astroglial reactions are confined to birds and mammals. To understand the function of post-lesion astroglial reaction, the phylogenetical aspects are also to be investigated. Considering the regenerative capabilities, reptiles represent an intermediate position between the brain regeneration-permissive fishes and amphibians and the almost non-permissive birds and mammals. Damage is followed by a rapid astroglial reaction in the mammalian and avian brain, which is held as an impediment of regeneration. In other vertebrates the reactions were usually observed following long survival periods together with signs of regeneration, therefore they can be regarded as concomitant phenomena of regeneration. The present study applies short post-lesion periods comparable to those seen in mammals and birds for astroglial reactions. Two species of lizards were used: gecko (leopard gecko, Eublepharis macularius, Blyth, 1854) and agama (bearded dragon, Pogona vitticeps, Ahl, 1926). The gecko brain is rich in GFAP whereas the agama brain is quite poor in this. Crocodilia, the closest extant relatives of birds were represented in this study by Cuvier's dwarf caiman (Paleosuchus palpebrosus, Cuvier, 1807). The post-lesion astroglial reactions of crocodilians have never been investigated. The injuries were stab wounds in the telencephalon. The survival periods lasted 3, 7, 10 or 14 days. Immunoperoxidase reactions were performed applying anti-GFAP, anti-vimentin and anti-nestin reagents. No rapid and demarcating astroglial reaction resembling that of mammalian or avian brains was found. Alterations of the perivascular immunoreactivities of laminin and β-dystroglycan as indicators of glio-vascular decoupling proved that the lesions were effective on astroglia. The capability of rapid and demarcating astroglial reaction seems to be confined to mammals and birds and to appear by separate, parallel evolution in them.
- PublicationOpen AccessSesión práctica: Cordados I. Tunicados, cefalocordados, peces, anfibios, reptiles(2017-09-15) Garcia, Mª Dolores; Arnaldos Sanabria, María Isabel; Clemente, Mª Eulalia; Presa Asensio, Juan José; Zoología y Antropología Física
- PublicationOpen AccessSesión Práctica: Cordados II. Tetrápodos. Anfibios, Reptiles y Anatomía de tetrápodo(2016-07-22) García, María Dolores; Arnaldos Sanabria, María Isabel; Clemente, María Eulalia; Presa Asensio, Juan José; Facultad de Biología; Departamento de Zoología y Antropología Física