Dynamics of calcium and its roles in the dendrite of the cerebellar Purkinje cell

Abstract

The calcium ion (Ca²⁺) serves as an important cellular messenger with spatio-temporally highly dynamic patterns. Not only Ca²⁺ entering from the plasma membrane but also Ca²⁺ released from intracellular store sites play crucial roles in neurons as well as in other cell types. The cerebellar Purkinje cell shows a variety of spatio-temporal Ca²⁺ dynamics in its rich arborization, and the Ca²⁺ release mechanism mediated by IP₃ receptors and ryanodine receptors has been shown to be crucial for the induction of long-term depression, a form of synaptic plasticity, in this neuron. Purkinje cells in a model mouse line of human neurodegenerative disease, spinocerebellar ataxia type 1, showed abnormal Ca²⁺ release properties, which indicated tight regulation of Ca²⁺ dynamics in the wild type Purkinje cell. Quantitative analysis of the complex Ca²⁺ dynamics in the Purkinje cell dendrite is still in progress to elucidate the link between external stimuli and the resultant biochemical changes.