UNASSIGNED: In the cerebellum, sensory information is conveyed to Purkinje cells (PC) via the granule cell/parallel fibre (PF) pathway. Plasticity at the PF-PC synapse is thought to be a mechanism of information storage in motor learning. The induction of synaptic plasticity in the cerebellum and elsewhere usually involves intracellular @entity141 signals. Unusually, postsynaptic @entity141 signaling in PF-PC spines does not involve ionotropic glutamatergic receptors, since postsynaptic NMDARs are absent and the AMPARs are @entity141 -impermeable; postsynaptic voltage-gated @entity141 channels therefore constitute the sole rapid @entity141 signaling mechanism. Low-threshold activated T-type @entity460 channels are present at the synapse, but their contribution to PF-PC synaptic responses is unknown. Taking advantage of TTA-P2, a selective T-type channel antagonist, we show in the @entity19 that inhibition of these channels reduces PF-PC EPSCs and EPSPs by 15-20  %. This contribution was preserved during sparse input and repetitive activity. We characterised the biophysical properties of native T-type channels in young animals and modelled their activation during simulated dendritic EPSP waveforms. The comparison of modelled and observed synaptic responses suggests that T-type channels only activate in spines that are strongly depolarized by their synaptic input, a process requiring a high spine neck resistance. This brief and local activation ensures that T-type channels rapidly deactivate, thereby limiting inactivation during repetitive synaptic activity. T-type channels are therefore ideally situated to provide synaptic @entity141 entry at PF-PC spines. This article is protected by copyright. All rights reserved.

Contribution of postsynaptic T-type XXXX channels to parallel fibre-Purkinje cell synaptic responses.

@entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca(2+)'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium']
@entity460 :: (MESH:D002118,Chemical) :: ['calcium']
