Localization of Presynaptic Plasticity Mechanisms Enables Functional Independence of Synaptic and Ectopic Transmission in the Cerebellum

Figure 11

Localization of plasticity mechanisms at the parallel fibre terminal. (a) Illustration of the signalling domains involved in activity-dependent long-term potentiation. Local calcium influx through R-type channels activates adenylyl cyclase, leading to potentiation of vesicle release at the active zone. (b) Illustration of the signalling domains involved in presynaptic depression by CB1 receptors and receptors. Activation of mGluR1 leads to local release of endocannabinoids in the active zone, possibly enhanced by postsynaptic activation. Activation of NMDA receptors leads to widespread tonic GABA increases that engage both synaptic and ectopic release sites. Arrows denote activation mechanisms, bars denote inhibition. PN: Purkinje neuron, PF: parallel fibre, IN: interneuron, and BGC: Bergmann glial cell. Synaptic sites in active zone activate PN AMPA receptors, and ectopic sites in terminal periphery activate BGC AMPA receptors.

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