Spontaneous release from mossy fiber terminals inhibits Ni 2 -sensitive T-type Ca2 channels of CA30 pyramidal neurons in the rat organotypic hippocampal slice

Abstract

Mossy fibers (axons arising from dentate granule cells) form large synaptic contacts exclusively onto the proximal apical dendrites of CA3 pyramidal neurons. They can generate large synaptic currents that occur in close proximity to the soma. These properties mean that active conductance in the proximal apical dendrite could have a disproportionate influence on CA3 pyramidal neuron excitability. Ni2+-sensitive T-type Ca2+ channels are important modulators of dendritic excitability. Here, we use an optical approach to determine the contribution of Ni2+ (100 μM)-sensitive Ca 2+ channels to action potential (AP) elicited Ca2+ flux in the soma, proximal apical and distal apical dendrites. At res..