THE ACTIVITY OF SYNAPTOSOMAL CALCIUM CHANNELS IS INVERSELY CORRELATEDWITH 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 t o determine whether any of the systems that govern calcium homeostasis in synaptosomes may be related to that difference in performance. A n egative correlation between initial (5 s) K+-stimulated Ca-45(2+) upta ke and the behavioral scores from the last testing sessions was obtain ed. 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 thro ugh synaptosomal voltage gated calcium channels in old rats is inverse ly correlated with their behavior. This may explain the beneficial eff ects of organic calcium channel blockers on behavioral performance in aged animals.