Module 10: Figure Purkinje cell global Ca2+ signals
Activation of a global Ca2+ signal in the dendritic tree of a Purkinje cell following parallel fibre stimulation.
The climbing fibres that innervate the proximal regions of the dendritic tree release glutamate that activates α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors on the Purkinje cell, resulting in membrane depolarization, which sets off a complex spike that lasts for about 25 ms. As this spike invades the dendritic tree, it activates the voltage-operated channels (VOCs), resulting in a global Ca2+ signal throughout the dendritic tree. In addition, the action potential invades the soma, but the resulting Ca2+ signal is relatively small and confined to the outer region because of the large surface-to-volume ratio (Module 10: Figure Ca2+ signals in Purkinje cell soma). Reproduced, with permission, from Eilers, J., Callewaert, G., Armstrong, C. and Konnerth, A. (1995) Calcium signaling in a marrow somatic submembrane shell during synaptic activity in cerebellar Purkinje neurons. Proc. Natl. Acad. Sci. U.S.A. 92:10272–10276. Copyright (1995) National Academy of Sciences, U.S.A.; see Eilers et al. 1995.