Two types of functionally distinct Ca(2+) 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.