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

Key Points: At the parallel fibre-Purkinje cell glutamatergic synapse, little or no Ca(2+) entry takes place through postsynaptic neurotransmitter receptors, although postsynaptic calcium increases are clearly involved in the synaptic plasticity. Postsynaptic voltage-gated Ca(2+) channels therefore constitute the sole rapid postsynaptic Ca(2+) signalling mechanism, making it essential to understand how they contribute to the synaptic signalling. Using a selective T-type calcium channel antagonist, we describe a T-type component of the EPSC that is activated by the AMPA receptor-mediated depolarization of the spine and thus will contribute to the local calcium dynamics.

T-type channel blockade impairs long-term potentiation at the parallel fiber-Purkinje cell synapse and cerebellar learning.

CaV3.1 T-type channels are abundant at the cerebellar synapse between parallel fibers and Purkinje cells where they contribute to synaptic depolarization. So far, no specific physiological function has been attributed to these channels neither as charge carriers nor more specifically as Ca(2+) carriers.

Measuring mitochondrial and cytoplasmic Ca2+ in EGFP expressing cells with a low-affinity calcium Ruby and its dextran conjugate.

The limited choice and poor performance of red-emitting calcium (Ca(2+)) indicators have hampered microfluorometric measurements of the intracellular free Ca(2+) concentration in cells expressing yellow- or green-fluorescent protein constructs. A long-wavelength Ca(2+) indicator would also permit a better discrimination against cellular autofluorescence than the commonly used fluorescein-based probes. Here, we report an improved synthesis and characterization of Calcium Ruby, a red-emitting probe consisting of an extended rhodamine chromophore (578/602 nm peak excitation/emission) conjugated to BAPTA and having an additional NH(2) linker arm.