British Journal of Nutrition

Research Article

Learning behaviour and cerebral protein kinase C, antioxidant status, lipid composition in senescence-accelerated mouse: influence of a phosphatidylcholine–vitamin B12 diet

Mei-Chu Hunga1, Koji Shibasakia1, Riki Yoshidaa1, Masao Satoa1 and Katsumi Imaizumia1 c1

a1 Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, Fukuoka 812-8581, Japan


Our objective was to determine whether dietary supplementation with phosphatidylcholine (PC) plus vitamin B12 could afford beneficial effects on biochemical and biophysical events in the brain of senescence-accelerated mouse (SAM) substrain SAMP8. We measured learning behaviour, hippocampal protein kinase C (PKC) activity, cerebral antioxidant status, phospholipid composition and fatty acid composition in 6-month-old SAMP8 and in age-matched controls (SAM substrain SAMR1). In comparison with SAMR1, SAMP8 showed a significant elevation in total grading score of senescence (P<0·05) and a significant decline in acquisition (P<0·05). SAMP8 had a lower hippocampal PKC activity and cerebral PKC-β mRNA abundance than SAMR1. SAMP8 had increased cerebral lipid peroxide levels and proportion of sphingomyelin, and a lower proportion of 20 : 4n-6 and 22 : 6n-3 in cerebral phosphtidylethanolamine than SAMR1. SAMP8 fed the PC combined with vitamin B12 diet had an increased PKC activity and a higher proportion of 22 : 6n-3 than SAMP8 fed the control diet. These results indicate the potential benefit of PC combined with vitamin B12 as a dietary supplement.

(Received June 22 2000)

(Revised January 23 2001)

(Accepted February 13 2001)


c1 *Corresponding author: Dr Katsumi Imaizumi, fax +81 092 642 3003, email