Arachidonic acid preserves hippocampal neuron membrane fluidity in senescent rats

Fukaya, Taisuke; Gondaira, Takumi; Kashiyae, Yasuto; Kotani, Susumu; Ishikura, Yoshiyuki; Fujikawa, Shigeaki; Kiso, Yoshinobu; Sakakibara, Manabu

doi:10.1016/j.neurobiolaging.2006.05.023

« Previous Next »Neurobiology of Aging
Volume 28, Issue 8 , Pages 1179-1186, August 2007

Arachidonic acid preserves hippocampal neuron membrane fluidity in senescent rats

Taisuke Fukaya
- Graduate School of High-Technology for Human Welfare, Tokai University, Numazu 410-0321, Shizuoka, Japan
Takumi Gondaira
- School of High-Technology for Human Welfare, Tokai University, Numazu 410-0321, Shizuoka, Japan
Yasuto Kashiyae
- School of High-Technology for Human Welfare, Tokai University, Numazu 410-0321, Shizuoka, Japan
Susumu Kotani
- Department of Pharmacology, School of Medicine, Kanazawa University, Kanazawa 920-8640, Ishikawa, Japan
Yoshiyuki Ishikura
- Institute of Health Care Science, SUNTORY Ltd. Shimamoto 618-8503, Osaka, Japan
Shigeaki Fujikawa
- Institute of Health Care Science, SUNTORY Ltd. Shimamoto 618-8503, Osaka, Japan
Yoshinobu Kiso
- Institute of Health Care Science, SUNTORY Ltd. Shimamoto 618-8503, Osaka, Japan
Manabu Sakakibara
- School of High-Technology for Human Welfare, Tokai University, Numazu 410-0321, Shizuoka, Japan
- Corresponding author. Tel.: +81 55 968 1111; fax: +81 55 968 1156.

Received 7 December 2005; received in revised form 29 March 2006; accepted 22 May 2006. published online 22 June 2006.

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 (τ), 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 τ 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.

Keywords: FRAP, Arachidonic acid, Membrane fluidity, Diffusion constant, Mobile fraction, Time constant, Senescent rat, LTP, Hippocampal pyramidal neuron