Title | Frequency-selective exocytosis by ribbon synapses of hair cells in the bullfrog's amphibian papilla. |
Publication Type | Journal Article |
Year of Publication | 2012 |
Authors | Patel SH, Salvi JD, Maoiléidigh DÓ, Hudspeth AJ |
Journal | J Neurosci |
Volume | 32 |
Issue | 39 |
Pagination | 13433-8 |
Date Published | 2012 Sep 26 |
ISSN | 1529-2401 |
Keywords | Animals, Biophysical Phenomena, Biophysics, Calcium, Electric Capacitance, Exocytosis, Hair Cells, Auditory, In Vitro Techniques, Membrane Potentials, Microscopy, Confocal, Models, Biological, Patch-Clamp Techniques, Rana catesbeiana, Synapses |
Abstract | 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. |
DOI | 10.1523/JNEUROSCI.1246-12.2012 |
Alternate Journal | J. Neurosci. |
PubMed ID | 23015434 |
PubMed Central ID | PMC3468150 |
Grant List | / / Howard Hughes Medical Institute / United States T32 GM007739 / GM / NIGMS NIH HHS / United States GM07739 / GM / NIGMS NIH HHS / United States |
Submitted by kej2006 on June 6, 2018 - 4:09pm