Module 10: Figure somatic and dendritic Ca2+ waves
Neuronal somatic and dendritic Ca2+ waves.
The Ca2+ that controls neuronal gene transcription may reach the nucleus by Ca2+ waves that initiate at the synapses and propagate down the spines and in to the nucleus. The entry of Ca2+ at synapses may ignite dendritic Ca2+ waves that propagate by means of inositol 1,4,5-trisphosphate (InsP3) receptors, which are located in the endoplasmic reticulum, that produce the regenerative Ca2+ signal through a process of Ca2+-induced Ca2+ release (CICR). Acetylcholine released from cholinergic neurons acts on muscarinic receptors to produce the InsP3 (yellow dots) that sensitizes the InsP3 receptors in the dendrites and soma that is necessary for wave propagation. A similar process could account for somatic waves spreading in from the surface of the soma.