LONG-TERM DIETARY STRAWBERRY, SPINACH, OR VITAMIN-E SUPPLEMENTATION RETARDS THE ONSET OF AGE-RELATED NEURONAL SIGNAL-TRANSDUCTION AND COGNITIVE-BEHAVIORAL DEFICITS

Recent research has indicated that increased vulnerability to oxidativ e stress may be the major factor involved in CNS functional declines i n aging and age-related neurodegenerative diseases, and that antioxida nts, e.g., vitamin E, may ameliorate or prevent these declines. Presen t studies examined whether long-term feeding of Fischer 344 rats, begi nning when the rats were 6 months of age and continuing for 8 months, with diets supplemented with a fruit or vegetable extract identified a s being high in antioxidant activity, could prevent the age-related in duction of receptor-mediated signal transduction deficits that might h ave a behavioral component. Thus, the following parameters were examin ed: (1) oxotremorine-enhanced striatal dopamine release (OX-K+-ERDA), (2) cerebellar beta receptor augmentation of GABA responding, (3) stri atal synaptosomal Ca-45(2+) clearance, (4) carbachol-stimulated GTPase activity, and (5) Morris water maze performance. The rats were given control diets or those supplemented with strawberry extracts (SE), 9.5 gm/kg dried aqueous extract (DAE), spinach (SPN 6.4 gm/kg DAE), or vi tamin E (500 IU/kg). Results indicated that SPN-fed rats demonstrated the greatest retardation of age-effects on all parameters except GTPas e activity, on which SE had the greatest effect, whereas SE and vitami n E showed significant but equal protection against these age-induced deficits on the other parameters. For example, OX-K+-ERDA enhancement was four times greater in the SPN group than in controls. Thus, phytoc hemicals present in antioxidant-rich foods such as spinach may be bene ficial in retarding functional age-related CNS and cognitive behaviora l deficits and, perhaps, may have some benefit in neurodegenerative di sease.