BioProject

Calyx of Held giant presynaptic terminals in the medial nucleus of the trapezoid body of the auditory brainstem form axosomatic synapses that have advanced to one of the best-studied synaptic system of the mammalian brain. More...

Calyx of Held giant presynaptic terminals in the medial nucleus of the trapezoid body of the auditory brainstem form axosomatic synapses that have advanced to one of the best-studied synaptic system of the mammalian brain. As the auditory system matures and adjusts to high fidelity synaptic transmission, the calyx undergoes extensive structural and functional changes: it is formed around postnatal day 3 (P3), achieves immature function until hearing onset around P10 and can be considered mature from P21 onwards. This setting provides the unique opportunity to examine the repertoire of genes driving synaptic structure and function. We performed cell type-specific gene expression profiling of globular bushy cells (GBCs), the neurons giving rise to the calyx of Held, at different maturational stages (P3, P8 and P21). Overall design: We identified GBCs by stereotaxic injection of fluorescently labelled retrograde tracer Cholera toxin B into the contralateral MNTB of anesthetized rats. Animals were sacrificed 24h after injection, the brain was taken out and flash frozen. 12µm thick brainstem cryosections were prepared and 200 fluorescently labelled GBCs per animal were excised from the VCN using laser microdissection. Cells were collected from 6 animals at P3 (synapse formation), 9 animals at P8 (juvenile synapse) and 5 animals at P21 (mature synapse). RNA was isolated from the collected cells and linearly amplified in order to perform cell-type specific expression profiling. Less...