Two types of functionally distinct Ca2+ stores in hippocampal neurons

It is widely assumed that inositol trisphosphate (IP 3 ) and ryanodine (Ry) receptors share the same Ca 2+ pool in central mammalian neurons. We now demonstrate that in hippocampal CA1 pyramidal neurons IP 3 - and Ry-receptors are associated with two functionally distinct intracellular Ca 2+ stores, respectively. While the IP 3 -sensitive Ca 2+ store refilling requires Orai2 channels, Ry-sensitive Ca 2+ store refilling involves voltage-gated Ca 2+ channels (VGCCs). Our findings have direct implications for the understanding of function and plasticity in these central mammalian neurons.