https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35344 Wed 17 Jul 2019 11:45:17 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35596 Wed 11 Sep 2019 14:24:41 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50760 24 months) mice had impaired performance in a balance beam task compared to young (3-4 months) adult mice. While there was no qualitative loss of cholinergic axon varicosities in the crista ampullaris of old mice, qPCR analysis revealed reduced expression of nicotinic receptor subunit genes Chrna1, Chrna9, and Chrna10 in the cristae of old relative to young mice. Functionally, single-cell patch clamp recordings taken from type II vestibular hair cells exposed to acetylcholine show reduced conductance through alpha9/10 subunit-containing nicotinic receptors in older mice, despite preserved passive membrane properties and voltage-activated conductances. These findings suggest that cholinergic signaling in the peripheral vestibular sensory organs is vulnerable to aging processes, manifesting in dynamic molecular and functional age-related changes. Given the importance of these organs to our everyday activities, and the dramatic increase in fall incidence in the elderly, further investigation into the mechanisms of altered peripheral vestibular function in older humans is warranted.]]> Mon 07 Aug 2023 14:22:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38005 3R) antagonist aminoethoxydiphenyl borate (2-APB). Results demonstrate long-lasting calcium transients are present in the utricular macula during the first postnatal week, and that responses to ACh mature over this same time period.]]> Fri 23 Jul 2021 14:58:44 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35648 -/-) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of a9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the a9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from a9^-/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of a9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of a9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted efferent mechanism for altering hair cell membrane potential and decreasing membrane resistance that should reduce sensitivity to hair bundle displacements.]]> Fri 18 Aug 2023 10:20:28 AEST ]]>