The mammalian brain is rich in the amino acid taurine that is synthesized via cysteine sulfinate decarboxylase (CSD). Taurine has been shown to be an inhibitory neuromodulator as well as a trophic factor essential for neuronal differentiation. Brain taurine has uneven regional distribution, being particularly concentrated in the main olfactory bulb, where it is the most abundant neuroactive amino acid, exceeding glutamate and GABA in concentration. A group of researchers has employed antiserum against CSD purified from rat liver to study the nature of taurineproducing cells in some brain regions. These studies localized CSD to astrocytes in the cerebellum and hippocampus, implying that brain synthesis of taurine is solely associated with glial cells. In the present study, immunohistochemical localization of CSD in the rat olfactory bulb was examined using polyclonal antibodies that we developed to a synthetic fragment of the CSD protein. With these antibodies, CSD immunoreactivity was found in primary olfactory afferents, various neurons in the glomerular and external plexiform layers, and in mitral cells. These elements also showed taurine immunoreactivity. Granule cells were immunonegative for CSD but contained taurine. The results demonstrate potential sites of taurine production in the main olfactory bulb and suggest that neuronal cells are involved in brain biosynthesis of taurine.
Immunohistochemical localization of taurine-synthesizing enzyme in the rat olfactory bulb
BELLUZZI, Ottorino
2002
Abstract
The mammalian brain is rich in the amino acid taurine that is synthesized via cysteine sulfinate decarboxylase (CSD). Taurine has been shown to be an inhibitory neuromodulator as well as a trophic factor essential for neuronal differentiation. Brain taurine has uneven regional distribution, being particularly concentrated in the main olfactory bulb, where it is the most abundant neuroactive amino acid, exceeding glutamate and GABA in concentration. A group of researchers has employed antiserum against CSD purified from rat liver to study the nature of taurineproducing cells in some brain regions. These studies localized CSD to astrocytes in the cerebellum and hippocampus, implying that brain synthesis of taurine is solely associated with glial cells. In the present study, immunohistochemical localization of CSD in the rat olfactory bulb was examined using polyclonal antibodies that we developed to a synthetic fragment of the CSD protein. With these antibodies, CSD immunoreactivity was found in primary olfactory afferents, various neurons in the glomerular and external plexiform layers, and in mitral cells. These elements also showed taurine immunoreactivity. Granule cells were immunonegative for CSD but contained taurine. The results demonstrate potential sites of taurine production in the main olfactory bulb and suggest that neuronal cells are involved in brain biosynthesis of taurine.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
