A good starting point for exploring this field.īootman, M. A comprehensive review of calcium sparks in different cell types that emphasizes results from cardiac myocytes. Physiology and pathophysiology of the calcium store in the endoplasmic reticulum of neurons. A new cellular mechanism for coupling inputs arriving at different cortical layers. NMDA spikes in basal dendrites of cortical pyramidal neurons. An influential review that highlights the importance of diverse calcium signals in architecturally complex dendrites and axons.Īugustine, G. However, many of their functions remain to be determined.īloodgood, B. Localized Ca 2+ release events have been correlated with the generation of inhibitory postsynaptic currents at certain synapses, and these events locally increase Ca 2+-activated K + conductances in some cells. However, several of their properties implicate the involvement of ryanodine receptors, suggesting that they are more complex than IP 3-mediated puffs. These localized events seem to contribute to the generation of large amplitude IP 3-mediated Ca 2+ waves. Their frequency can also be modulated by mGluR-mediated mobilization of IP 3. The frequency of these events in dendrites can be modulated by changes in membrane potential in the subthreshold range, primarily by controlling Ca 2+ entry through voltage-gated calcium channels. These events resemble 'sparks' and 'puffs', which have been observed in many non-neuronal cell types. In addition to large-amplitude, widespread Ca 2+ waves, localized, smaller amplitude, spontaneous Ca 2+ release events have been detected in the soma, dendrites and presynaptic termini of many CNS neurons. However, many of these results are controversial. Postsynaptic Ca 2+ release and Ca 2+ waves have been implicated in the modulation of membrane conductances and the induction of several forms of synaptic plasticity, including long-term potentiation and long-term depression. The range of wave propagation in dendrites depends on the number and location of synaptic inputs and the influence of neuromodulators. The waves are evoked by metabotropic glutamate receptor (mGluR) mobilization of inositol trisphosphate (IP 3) that regeneratively releases Ca 2+ through IP 3 receptors. In many pyramidal neurons in the hippocampus, cortex and amygdala, Ca 2+ release propagates as a wave in restricted regions of dendrites. Ca 2+ release can be widespread and substantial, but often has no correlated change in membrane potential. Synaptic stimulation evokes postsynaptic intracellular calcium concentration ( i) changes via Ca 2+ entry through ligand- and voltage-gated channels and via Ca 2+ release from internal stores.
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