THE ACTIVITY OF SYNAPTOSOMAL CALCIUM CHANNELS IS INVERSELY CORRELATED WITH WORKING-MEMORY PERFORMANCE IN MEMORY-IMPAIRED, AGED RATS

Aged, memory-impaired rats do not learn an 8-arm radial maze task but differ in their performance along testing. The aim of this study was to determine whether any of the systems that govern calcium homeostasis in synaptosomes may be related to that difference in performance. A negative correlation between initial (5 s) K+-stimulated Ca-45(2+) uptake and the behavioral scores from the last testing sessions was obtained. K+-stimulated Ca-45(2+) uptake showed also a negative correlation with an improvement score that evaluates the progress made by the rat along testing. The results support the notion that calcium inflow through synaptosomal voltage gated calcium channels in old rats is inversely correlated with their behavior. This may explain the beneficial effects of organic calcium channel blockers on behavioral performance in aged animals.