Alterations in calcium signaling and a decrease in Bcl‐2 expression: Possible correlation with apoptosis in aged striatum

Abstract Aging is a multifaceted process associated with various functional and structural deficits that might be evolved in degenerative diseases. It has been shown that neurodegenerative disorders are associated with alterations in Ca 2+ homeostasis. Thus, in the present work, we have investigated Ca 2+ signaling and apoptosis in aged striatum. Our results show that glutamate and NMDA evoke a greater Ca 2+ rise in striatum slices from aged animals. However, this difference is not present when glutamate is tested in the absence of external Ca 2+ . Immunostaining of glutamate receptors shows that only NMDA receptors (NR1) are increased in the striatum of aged rats. Increases in mitochondrial Ca 2+ content and in the reactive oxygen species levels were also observed in aged animals, which could be associated with tissue vulnerability. In addition, a decrease in the Bcl‐2 protein expression and an enhancement in apoptosis were also present in aged striatum. Together the results indicate that, in aged animals, alterations in Ca 2+ handling coupled to an increase in ROS accumulation and a decrease in the prosurvival protein Bcl‐2 may contribute to apoptosis induction and cell death in rat striatum. © 2009 Wiley‐Liss, Inc.