title: Polysialylated neural cell adhesion molecule expression in the dentate gyrus of the human hippocampal formation from infancy to old age.
abstract: Modulation of neural cell adhesion molecule polysialylation (NCAM PSA) state has been proposed to underlie morphofunctional change associated with consolidation of memory in the rodent, and its age-dependent decline to be related to impaired cognitive function. To establish whether this may be a human correlate of cognitive decline, we determined the age-dependent expression of PSA in the human hippocampal dentate gyrus using postmortem tissue derived from individuals who exhibited no obvious neuropathology. As in the rodent, PSA immunoreactivity in the 5-month human infant was associated mainly with a population of granule-like cells and their mossy fibre axons. Cell numbers were maximal during the first 3 years of life but declined by an order of magnitude between the second and third decades and remained relatively constant thereafter and was restricted to the granule cell layer/hilar border. In contrast to the rodent, diffuse immunostaining was observed in the inner molecular layer; however, as development advanced, this became relocated to the outer molecular layer from 2 years of age onwards. In addition, numerous polysialylated hilar neurons became evident at 2-3 years of age and remained constant until the eighth decade of life. These findings suggest NCAM polysialylation to play a crucial developmental role within a period concluding with adolescence, and that an attenuated NCAM PSA-mediated neuroplasticity continues throughout the human lifespan. The importance of the developmental phase of NCAM PSA expression in the emergence of schizophrenia is discussed.
authors.affiliation: Department of Pharmacology, University College, Belfield, Dublin, Ireland.
authors.forename: C M
authors.initials: CM
authors.lastname: Ní Dhúill
authors.forename: G B
authors.initials: GB
authors.lastname: Fox
authors.forename: S J
authors.initials: SJ
authors.lastname: Pittock
authors.forename: A W
authors.initials: AW
authors.lastname: O'Connell
authors.forename: K J
authors.initials: KJ
authors.lastname: Murphy
authors.forename: C M
authors.initials: CM
authors.lastname: Regan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002675:Child, Preschool; D018891:Dentate Gyrus / Q000378:metabolism* / Q000502:physiology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*
chemical_list: D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule