Home About us Contact
|
Home About us Contact | ||
|
|
||
Ramón Y Cajal (ramón + y_cajal)
Selected AbstractsRecent progress on the molecular organization of myelinated axonsJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2002Steven S. Scherer Abstract The structure of myelinated axons was well described 100 years ago by Ramón y Cajal, and now their molecular organization is being revealed. The basal lamina of myelinating Schwann cells contains laminin-2, and their abaxonal/outer membrane contains two laminin-2 receptors, ,6,4 integrin and dystroglycan. Dystroglycan binds utrophin, a short dystrophin isoform (Dp116), and dystroglycan-related protein 2 (DRP2), all of which are part of a macromolecular complex. Utrophin is linked to the actin cytoskeleton, and DRP2 binds to periaxin, a PDZ domain protein associated with the cell membrane. Non-compact myelin,found at incisures and paranodes,contains adherens junctions, tight junctions, and gap junctions. Nodal microvilli contain F-actin, ERM proteins, and cell adhesion molecules that may govern the clustering of voltage-gated Na+ channels in the nodal axolemma. Nav1.6 is the predominant voltage-gated Na+ channel in mature nerves, and is linked to the spectrin cytoskeleton by ankyrinG. The paranodal glial loops contain neurofascin 155, which likely interacts with heterodimers composed of contactin and Caspr/paranodin to form septate-like junctions. The juxtaparanodal axonal membrane contains the potassium channels Kv1.1 and Kv1.2, their associated ,2 subunit, as well as Caspr2. Kv1.1, Kv1.2, and Caspr2 all have PDZ binding sites and likely interact with the same PDZ binding protein. Like Caspr, Caspr2 has a band 4.1 binding domain, and both Caspr and Caspr2 probably bind to the band 4.1B isoform that is specifically found associated with the paranodal and juxtaparanodal axolemma. When the paranode is disrupted by mutations (in cgt -, contactin -, and Caspr -null mice), the localization of these paranodal and juxtaparanodal proteins is altered: Kv1.1, Kv1.2, and Caspr2 are juxtaposed to the nodal axolemma, and this reorganization is associated with altered conduction of myelinated fibers. Understanding how axon-Schwann interactions create the molecular architecture of myelinated axons is fundamental and almost certainly involved in the pathogenesis of peripheral neuropathies. [source] Origin and Endpoint of the Olfactory Nerve Fibers: As Described by Santiago Ramón y Cajal,THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 7 2008Catherine Levine Illustration by author Catherine Levine inspired by the original drawing by Santiago Ramón y Cajal, featured in the article Origin and endpoint of the olfactory nerve fibers: As described by Santiago Ramón y Cajal. Depicted are large tufted cells and granule cells, a large stellate cell, a row of mitral cells and the arborization on the olfactory glomeruli, with olfactory nerve fibers streaming through the cartilage formation of the cribriform plate. See Levine et al., Anatomical Record 291:741,750. [source] Nobel Prizes in paediatrics: Santiago Ramón y Cajal (1852,1934) and the founding of neuroembryologyACTA PAEDIATRICA, Issue 2 2006Hugo LagercrantzArticle first published online: 2 JAN 200 No abstract is available for this article. [source] | ||||||||||