Morphological and functional changes in the distal hypothalamo-neurohypophysial system of the grass frog (Rana pipiens) after transection of the proximal neurohypophysis

Zusammenfassung Nach Durchtrennung der proximalen Neurohypophyse wird im distalen Stumpf eine gegenüber Kontrolltieren erhöhte Menge paraldehyd-fuchsinpositiver Substanz gefunden, die im Elektronenmikroskop einwandfrei als Neurosekret identifiziert werden konnte. Die im Tierversuch ermittelte erhöhte, blutdrucksteigernde Aktivität des distalen Teils der Neurohypophyse spricht für eine lokale Synthese des Neurosekrets.

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Supported by NIH Grant No. NB 06641 and the Space Sciences Research Center of the University of Missouri.     

Autotaxin (NPP-2) in the brain: cell type-specific expression and regulation during development and after neurotrauma

Autotaxin is a secreted cell motility-stimulating exo-phosphodiesterase with lysophospholipase D activity that generates bioactive lysophosphatidic acid. Lysophosphatidic acid has been implicated in various neural cell functions such as neurite remodeling, demyelination, survival and inhibition of axon growth. Here, we report on the in vivo expression of autotaxin in the brain during development and following neurotrauma. We found that autotaxin is expressed in the proliferating subventricular and choroid plexus epithelium during embryonic development. After birth, autotaxin is mainly found in white matter areas in the central nervous system. In the adult brain, autotaxin is solely expressed in leptomeningeal cells and oligodendrocyte precursor cells. Following neurotrauma, autotaxin is strongly up-regulated in reactive astrocytes adjacent to the lesion. The present study revealed the cellular distribution of autotaxin in the developing and lesioned brain and implies a function of autotaxin in oligodendrocyte precursor cells and brain injuries. Received 18 September 2006; received after revision 30 October 2006; accepted 4 December 2006