Function of SERCA mediated calcium uptake and expression of SERCA3 in cerebral cortex from young and old rats

Previous work on peripheral sympathetic neurons indicated that a decline in sarco/endoplasmic reticulum calcium ATPase (SERCA) function occurs with ad vancing age. Therefore, an age-related decline in mechanisms controlling in tracellular calcium homeostasis could contribute to altered neuronal functi on and/or degeneration. In this study we sought to extend the findings on p eripheral neurons and to detect possible age-related declines in SERCA func tion and expression of SERCA3 in central neurons from cerebral cortex from young (6-month) and old (20-month) rats. Functional studies compared ATP-de pendent (4)5Ca(2+)-uptake into microsomes and plasma membrane vesicles (PMV s). We and found no significant difference in Ca-45(2+)-uptake between micr osomes or PMVs between young and old animals. On the other hand expression of SERCA3 mRNA in rat cerebral cortex showed a significant decline with adv ancing age. However, comparison of SERCA3 protein content did not reveal a corresponding decline; implying that SERCA mRNA turnover rates may be great er in the younger group. Although the present work with rat cerebral cortex does not indicate an age-related decline in SERCA function, previous work from our laboratory on sympathetic nerves and by others on the hippocampus indicate such a decline. In light of our previous and current studies, agin g may affect calcium homeostatic mechanisms in central and peripheral auton omic neurons differently, (C) 2001 Elsevier Science BY All rights reserved.