Figure 9.
Proposed model of the Cav3.2 channel as a critical switch for mature granule cells to support synaptic plasticity and be effective in transmitting information to the CA3 pyramids. A schematic mature granule cell sending axonal projections to CA3 pyramidal neurons, representing 2 different conditions of Cav3.2 channel activity. Top half: Cav3.2 current (ICav3.2) enhances the ability of mature granule cells to generate high-frequency bursts of action potentials. This process, in turn, facilitates synaptic plasticity in the proper granule cells and produces a sufficiently strong stimulation of the postsynaptic CA3 pyramidal neurons to initiate spikes. Bottom half: low numbers of Cav3.2 channels or downregulation of their activity results in a reduced ICav3.2. As a consequence, mature granule cells are impaired in their ability to produce action potential bursts. This translates to reduced synaptic plasticity and inefficient stimulation of postsynaptic CA3 pyramidal cells.