Frequency-selective Exocytosis by Ribbon Synapses of Hair Cells in the Bullfrog's Amphibian Papilla
Overview
Affiliations
The activity of auditory afferent fibers depends strongly on the frequency of stimulation. Although the bullfrog's amphibian papilla lacks the flexible basilar membrane that effects tuning in mammals, its afferents display comparable frequency selectivity. Seeking additional mechanisms of tuning in this organ, we monitored the synaptic output of hair cells by measuring changes in their membrane capacitance during sinusoidal electrical stimulation at various frequencies. Using perforated-patch recordings, we found that individual hair cells displayed frequency selectivity in synaptic exocytosis within the frequency range sensed by the amphibian papilla. Moreover, each cell's tuning varied in accordance with its tonotopic position. Using confocal imaging, we observed a tonotopic gradient in the concentration of proteinaceous Ca(2+) buffers. A model for synaptic release suggests that this gradient maintains the sharpness of tuning. We conclude that hair cells of the amphibian papilla use synaptic tuning as an additional mechanism for sharpening their frequency selectivity.
Otoferlin as a multirole Ca signaling protein: from inner ear synapses to cancer pathways.
Leclere J, Dulon D Front Cell Neurosci. 2023; 17:1197611.
PMID: 37538852 PMC: 10394277. DOI: 10.3389/fncel.2023.1197611.
Zhao J, Yin N, Li G Front Cell Neurosci. 2023; 16:1064886.
PMID: 36700157 PMC: 9868640. DOI: 10.3389/fncel.2022.1064886.
Differential Gene Expression Patterns Between Apical and Basal Inner Hair Cells Revealed by RNA-Seq.
Tang F, Chen X, Jia L, Li H, Li J, Yuan W Front Mol Neurosci. 2020; 12:332.
PMID: 32038162 PMC: 6985465. DOI: 10.3389/fnmol.2019.00332.
Azimzadeh J, Salvi J J Vis Exp. 2017; (121).
PMID: 28362415 PMC: 5408964. DOI: 10.3791/55380.
Johnson S, Olt J, Cho S, von Gersdorff H, Marcotti W J Neurosci. 2017; 37(9):2471-2484.
PMID: 28154149 PMC: 5354352. DOI: 10.1523/JNEUROSCI.2867-16.2017.