caa a22 4500 445351055 CHVBK 20180317142844.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s00221-011-2592-4 doi (NATIONALLICENCE)springer-10.1007/s00221-011-2592-4 Potassium accumulation between type I hair cells and calyx terminals in mouse crista [Elektronische Daten] [Rebecca Lim, Angela Kindig, Scott Donne, Robert Callister, Alan Brichta] The mode of synaptic transmission in the vestibular periphery, between type I hair cells and their associated calyx terminal, has been the subject of much debate. The close and extensive apposition of pre- and post-synaptic elements has led some to suggest potassium (K+) accumulates in the intercellular space and even plays a role in synaptic transmission. During patch clamp recordings from isolated and embedded hair cells in a semi-intact preparation of the mouse cristae, we noted marked differences in whole-cell currents. Embedded type I hair cells show a prominent droop during steady-state activation as well as a dramatic collapse in tail currents. Responses to a depolarizing voltage step (−124 to +16mV) in embedded, but not isolated, hair cells resulted in a >40mV shift of the K+ equilibrium potential and a rise in effective K+ concentration (>50mM) in the intercellular space. Together these data suggest K+ accumulation in the intercellular space accounts for the different responses in isolated and embedded type I hair cells. To test this notion, we exposed the preparation to hyperosmotic solutions to enlarge the intercellular space. As predicted, the K+ accumulation effects were reduced; however, a fit of our data with a classic diffusion model suggested K+ permeability, rather than the intercellular space, had been altered by the hyperosmotic change. These results support the notion that under depolarizing conditions substantial K+ accumulation occurs in the space between type I hair cells and calyx. The extent of K+ accumulation during normal synaptic transmission, however, remains to be determined. Springer-Verlag, 2011 Type I hair cell nationallicence Calyx terminal nationallicence Potassium accumulation nationallicence Voltage clamp nationallicence Hyperosmotic nationallicence Lim Rebecca School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut Kindig Angela School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut Donne Scott School of Environmental and Life Sciences, Faculty of Science and Information Technology, The University of Newcastle, 2308, Callaghan, NSW, Australia aut Callister Robert School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut Brichta Alan School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut Experimental Brain Research Springer-Verlag 210/3-4(2011-05-01), 607-621 0014-4819 210:3-4<607 2011 210 221 https://doi.org/10.1007/s00221-011-2592-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00221-011-2592-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lim Rebecca School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut NATIONALLICENCE 700 1- Kindig Angela School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut NATIONALLICENCE 700 1- Donne Scott School of Environmental and Life Sciences, Faculty of Science and Information Technology, The University of Newcastle, 2308, Callaghan, NSW, Australia aut NATIONALLICENCE 700 1- Callister Robert School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut NATIONALLICENCE 700 1- Brichta Alan School of Biomedical Sciences & Pharmacy, Faculty of Health, The University of Newcastle, and Hunter Medical Research Institute, 2308, Callaghan, NSW, Australia aut NATIONALLICENCE 773 0- Experimental Brain Research Springer-Verlag 210/3-4(2011-05-01), 607-621 0014-4819 210:3-4<607 2011 210 221 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer