Jf. Flood et al., AGE-RELATED-CHANGES IN HIPPOCAMPAL DRUG FACILITATION OF MEMORY PROCESSING IN SAMP8 MICE, Neurobiology of aging, 17(1), 1996, pp. 15-24
SAMP8/TaJf(P8) mouse strain has an inherited age-related impairment of
learning and memory, while age-matched subjects of the closely relate
d SAMR1/TaJf(R1) show no impairment. After training on footshock avoid
ance, P8 and R1 received a drug injection into the hippocampus. Retent
ion was tested 1 week later. The results indicate that bicuculline (GA
BA antagonist), SKF38393 (DA agonist), and ST587 (NE agonist) facilita
ted retention with little change in the dose-response curves for P8 mi
ce 4, 8, and 12 months of age. L-glutamate, acting at the NMDA recepto
r, showed a modest decline in ability to improve retention with increa
sing age. Arecoline, a muscarinic agonist, had the strongest trend for
an age-related decline in potency. The same drug treatments yielded d
ose-dependent facilitation of retention but no age-related changes in
R1 mice. Reduced cholinergic activity in the hippocampus may be, in pa
rt, responsible for age-related decline in memory retention in P8 mice
.