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Titolo:
The polysialylated neural cell adhesion molecule reaches cell surfaces of hypothalamic neurons and astrocytes via the constitutive pathway
Autore:
Pierre, K; Bonhomme, R; Dupouy, B; Poulain, DA; Theodosis, DT;
Indirizzi:
Univ Bordeaux 2, Inst Francois Magendie, INSERM, U378, F-33077 Bordeaux, France Univ Bordeaux 2 Bordeaux France F-33077 , U378, F-33077 Bordeaux, France
Titolo Testata:
NEUROSCIENCE
fascicolo: 1, volume: 103, anno: 2001,
pagine: 133 - 142
SICI:
0306-4522(2001)103:1<133:TPNCAM>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYPOTHALAMONEUROHYPOPHYSEAL SYSTEM; N-CAM; NEUROHYPOPHYSEAL SYSTEM; MAGNOCELLULAR NEURONS; ORGANOTYPIC CULTURES; SYNAPTIC PLASTICITY; OXYTOCIN NEURONS; GLYCOPROTEIN F3; NERVOUS-SYSTEM; ADULT-RAT;
Keywords:
adhesion molecules; constitutive secretion; oxytocin neurons; astrocytes; organotypic slice cultures;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Theodosis, DT Univ Bordeaux 2, Inst Francois Magendie, INSERM, U378, 1 RueCamille St Saens, F-33077 Bordeaux, France Univ Bordeaux 2 1 Rue Camille St Saens Bordeaux France F-33077
Citazione:
K. Pierre et al., "The polysialylated neural cell adhesion molecule reaches cell surfaces of hypothalamic neurons and astrocytes via the constitutive pathway", NEUROSCIENC, 103(1), 2001, pp. 133-142

Abstract

Understanding how neurons and glia sort and deliver cell adhesion molecules to their cell surface should provide important clues as to how such molecules participate in dynamic neuronal functions in the developing and adult brain. The present study examines translocation of polysialylated neural cell adhesion molecule (PSA-NCAM), a negative regulator of cell adhesion. in cells of the rat hypothalamo-neurohypophysial system in which it is expressed throughout life and which undergo morphological remodelling in response to stimulation. PSA-NCAM expression in this system does not vary markedly in relation to different conditions of regulated neurosecretion, suggesting that the glycoprotein reaches cell surfaces via the constitutive pathway. To study this more directly, we here used immunofluorescence for PSA on NCAMin live, unpermeabilized cells to monitor PSA-NCAM surface expression in organotypic slice cultures from postnatal rat hypothalami. Subsequent immunolabelling for oxytocin confirmed that the cultures included magnocellular oxytocinergic neurons displaying many properties of adult neurosecretory neurons in situ. In the cultures, immunoreaction for PSA-NCAM was visible on the surface ofoxytocinergic and non-oxytocinergic axons. This reaction disappeared afterexposure of the cultures to endoneuraminidase, an enzyme which specifically cleaves alpha -2-8-linked PSA from NCAM. PSA-NCAM reappeared on axonal surfaces 4 h after enzyme washout. Such reexpression was visibly not affectedby neuronal activity inhibition (blockade of Ca2+ channels with Mn2+, of Na+ channels with tetrodotoxin, or of glutamate receptors with 6-cyano-7-nitroquinoxaline-2.3-dione or D-2 amino-5-phosphonopentanoic acid) or facilitation (K+ depolarization or GABA-A receptor blockade with bicuculline). In contrast, PSA-NCAM surface translocation was inhibited reversibly by coolingthe cultures at 20 degreesC, a procedure which blocks constitutive secretion and which resulted in accumulation of PSA-NCAM in the cytoplasm of oxytocinergic and non-oxytocinergic neurons. This treatment also revealed PSA-NCAM in the cytoplasm of underlying astrocytes. Our observations provide direct evidence that PSA-NCAM reaches the cell surface of hypothalamic neurons and astrocytes via the constitutive pathway, independently of Ca2+ entry and enhanced neuronal activity. Thus, PSA-NCAM in the hypothalamo-neurohypophysial system would be continuously available to permit its cells to undergo remodelling whenever the proper stimulus intervenes. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 16:28:07