TY - JOUR T1 - Ca<sup>2+</sup> Signaling in Mouse Cortical Neurons Studied by Two-Photon Imaging and Photoreleased Inositol Triphosphate JF - The Journal of Neuroscience JO - J. Neurosci. SP - 758 LP - 765 DO - 10.1523/JNEUROSCI.23-03-00758.2003 VL - 23 IS - 3 AU - Grace E. Stutzmann AU - Frank M. LaFerla AU - Ian Parker Y1 - 2003/02/01 UR - http://www.jneurosci.org/content/23/3/758.abstract N2 - IP3-mediated Ca2+ release is a crucial neuronal signaling mechanism that has not been extensively characterized in the mammalian cerebral cortex. We used two-photon, video-rate microscopy to image Ca2+ signals evoked by photoreleased IP3 in pyramidal neurons of mouse prefrontal cortex. Ca2+ responses to photoreleased IP3 varied greatly between different neurons; however, within IP3-responsive neurons, the soma invariably showed highest sensitivity, with signals increasing nonlinearly with [IP3]. Responses to paired photorelease displayed inhibition, whereas IP3-evoked Ca2+liberation was potentiated by Ca2+ entry during action potentials and vice versa. IP3-mediated Ca2+ signals strongly inhibited spike firing through activation of K+ membrane conductance. Metabotropic signaling via the phosphoinositide pathway thus serves as a powerful and sustained modulator of excitability in cortical neurons and displays complex reciprocal interactions between electrical and chemical signals. ER -