title: Arachidonic acid preserves hippocampal neuron membrane fluidity in senescent rats.
abstract: Previous studies indicate that long-term dietary supplementation with arachidonic acid (AA) in 20-month-old rats (OA) effectively restores performance in a memory task and the induction of long-term potentiation in the hippocampus to the level of young control animals (YC). The present study examined protein mobility using the live cell imaging technique "Fluorescent Recovery After Photobleaching (FRAP)" in YC, old control (OC) and OA neurons in hippocampal slice preparations. Three measures; mobile fraction (M(f)), diffusion constant (D) and time constant (tau), were estimated among YC, OC and OA. Each of these parameters was significantly different between OC and YC, suggesting that membrane fluidity is lower in OC than in YC. In contrast, D and tau were comparable in OA and YC, indicating that hippocampal neuronal membranes supplemented with AA were more fluid than those in OC, whereas the fraction of diffusible protein in the bleached region remained smaller than in YC. Long-term administration of AA to senescent rats might help to preserve membrane fluidity and maintain hippocampal plasticity.
authors.affiliation: Graduate School of High-Technology for Human Welfare, Tokai University, Numazu 410-0321, Shizuoka, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Fukaya
authors.forename: Takumi
authors.initials: T
authors.lastname: Gondaira
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Kashiyae
authors.forename: Susumu
authors.initials: S
authors.lastname: Kotani
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ishikura
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Fujikawa
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kiso
authors.forename: Manabu
authors.initials: M
authors.lastname: Sakakibara
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D016718:Arachidonic Acid / Q000502:physiology*; D019587:Dietary Supplements; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D010782:Photolysis; D051381:Rats; D011916:Rats, Inbred F344; D013050:Spectrometry, Fluorescence / Q000379:methods; D013997:Time Factors
chemical_list: D016718:Arachidonic Acid