Hair cells contain an osmophilic dense body, often called a synaptic ribbon, to which many functions have been ascribed.
We are directly investigating the function of the dense body using whole animal and single cell electrophysiology both pre and post synaptic recordings, super resolution quantitative immunocytochemistry, high speed confocal calcium imaging and genetic manipulations.
Multiple functions have been ascribed to the synaptic ribbon. These functions include: maintaining a high number of vesicles near release sites, being a site for generation of new synaptic vesicles, controlling multivesicular release, regulating timing of vesicle fusion and creating a barrier to calcium diffusion. We are taking a multidisciplinary approach to unravelling the underlying functions and associated molecular mechanisms. We use a multisine stimulus paradigm to track vesicle fusion by monitoring membrane capacitance. We use postsynaptic recordings to assess synaptic function. We are also using molecular tools such as voltage sensors to track activity in multiple fibers, and genetic tools such as ribeye knockout animals to investigate the function of the synaptic ribbon. High speed confocal calcium imaging coupled with peptides that label synapses are also included in these studies. And finally, we include immunocytochemistry and electron microscopy.