Immunolocalization of polysialic acid in the median eminence and neurointermediate hypophysial lobe of adult rats.
Polysialic acid (PSA) is abundant on growing axons during brain development and down regulated on maturation. However, high amounts of this carbohydrate polymer have been found to persist in some regions of the adult rat brain including the mediobasal hypothalamus. In this study, confocal laser scanning microscopy combined with double fluorescence immunostaining was used to characterize the cellular localization of PSA throughout the median eminence and neurointermediate hypophysial lobe of adult rats. In these regions, polysialic acid-immunoreactivity (PSA-IR) generally appeared associated with fiber-like structures. Double immunostaining experiments demonstrated that, in addition to large axons of the neural lobe immunoreactive to vasopressin or oxytocin, PSA was constantly associated with fibers projecting into the intermediate hypophysial lobe immunoreactive to either gamma-aminobutyric acid (GABA) or tyrosine hydroxylase. Similarly, PSA-IR was detected on most, but not all the fibers immunoreactive to GABA or tyrosine hydroxylase dispersed throughout the neural lobe and the different layers of the median eminence. On the other hand, no PSA-IR was detected on axons immunoreactive to somatostatin or to corticotropin releasing hormone projecting throughout the median eminence, or on glial cell bodies and processes immunoreactive for glial fibrillary acidic protein (GFAP) or for vimentin dispersed throughout the median eminence and the neural lobe.
Alonso
G
G
INSERM U 336, Développement, Plasticité et Vieillissement du Système Nerveux, Université de Montpellier II, France.
D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012794:Sialic Acids / Q000032:analysis*; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis; D014746:Vimentin / Q000032:analysis; D005680:gamma-Aminobutyric Acid / Q000032:analysis
D015816:Cell Adhesion Molecules, Neuronal; D005904:Glial Fibrillary Acidic Protein; D012794:Sialic Acids; D014746:Vimentin; C021319:polysialic acid; D005680:gamma-Aminobutyric Acid; D014446:Tyrosine 3-Monooxygenase