title: N-methyl-D-aspartate receptor density and membrane fluidity as possible determinants of the decline of passive avoidance performance in aging.
abstract: The effect of aging on three different parameters possibly relevant for cognition was investigated in female Naval Medical Research Institute mice: a) N-methyl-D-aspartate (NMDA) receptor density, as determined by the specific binding of [3H]MK-801 to forebrain membranes, decreased by 22% in aged (23 mo) and by 19% in middle-aged (12 mo) animals compared with young (3 mo) animals. b) In a passive avoidance acquisition task, the 24-h latency decreased significantly with age; the middle-aged mice also tended to show impairment in this task. c) The fluidity of the forebrain membranes also decreased significantly with age. Again, there was a significant reduction in the middle-aged group. A comparison of these parameters revealed significant correlations between NMDA receptor density and 24-h latency (r = 0.52, p < 0.003) over all three age groups, as well as significant correlations between membrane fluidity and either NMDA receptor density or 24-h latency. These findings do not prove a causal relationship, but are compatible with the hypothesis that changes of membrane fluidity, by decreasing the number of NMDA receptors, affect passive avoidance performance.
authors.affiliation: Central Institute for Mental Health, Department of Psychopharmacology, Mannheim, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Scheuer
authors.forename: S
authors.initials: S
authors.lastname: Stoll
authors.forename: U
authors.initials: U
authors.lastname: Paschke
authors.forename: R
authors.initials: R
authors.lastname: Weigel
authors.forename: W E
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000375:Aging / Q000502:physiology* / Q000523:psychology; D000818:Animals; D016880:Anisotropy; D001362:Avoidance Learning / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology; D002462:Cell Membrane / Q000502:physiology; D016291:Dizocilpine Maleate; D005260:Female; D007700:Kinetics; D008560:Membrane Fluidity / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate