PT - JOURNAL ARTICLE AU - Grace E. Stutzmann AU - Ian Smith AU - Antonella Caccamo AU - Salvatore Oddo AU - Frank M. LaFerla AU - Ian Parker TI - Enhanced Ryanodine Receptor Recruitment Contributes to Ca<sup>2+</sup> Disruptions in Young, Adult, and Aged Alzheimer's Disease Mice AID - 10.1523/JNEUROSCI.0739-06.2006 DP - 2006 May 10 TA - The Journal of Neuroscience PG - 5180--5189 VI - 26 IP - 19 4099 - http://www.jneurosci.org/content/26/19/5180.short 4100 - http://www.jneurosci.org/content/26/19/5180.full SO - J. Neurosci.2006 May 10; 26 AB - Neuronal Ca2+ signaling through inositol triphosphate receptors (IP3R) and ryanodine receptors (RyRs) must be tightly regulated to maintain cell viability, both acutely and over a lifetime. Exaggerated intracellular Ca2+ levels have been associated with expression of Alzheimer's disease (AD) mutations in young mice, but little is known of Ca2+ dysregulations during normal and pathological aging processes. Here, we used electrophysiological recordings with two-photon imaging to study Ca2+ signaling in nontransgenic (NonTg) and several AD mouse models (PS1KI, 3xTg-AD, and APPSweTauP301L) at young (6 week), adult (6 months), and old (18 months) ages. At all ages, the PS1KI and 3xTg-AD mice displayed exaggerated endoplasmic reticulum (ER) Ca2+ signals relative to NonTg mice. The PS1 mutation was the predominant “calciopathic” factor, because responses in 3xTg-AD mice were similar to PS1KI mice, and APPSweTauP301L mice were not different from controls. In addition, we uncovered powerful signaling interactions and differences between IP3R- and RyR-mediated Ca2+ components in NonTg and AD mice. In NonTg mice, RyR contributed modestly to IP3-evoked Ca2+, whereas the exaggerated signals in 3xTg-AD and PS1KI mice resulted primarily from enhanced RyR-Ca2+ release and were associated with increased RyR expression across all ages. Moreover, IP3-evoked membrane hyperpolarizations in AD mice were even greater than expected from exaggerated Ca2+ signals, suggesting increased coupling efficiency between cytosolic [Ca2+] and K+ channel regulation. We conclude that lifelong ER Ca2+ disruptions in AD are related to a modulation of RyR signaling associated with PS1 mutations and represent a discrete “calciumopathy,” not merely an acceleration of normal aging.