Abstract
Whereas prehearing spiral ganglion neurons (SGNs) rely faithfully on outputs from spontaneously active developing hair cells, the electrical phenotypes of posthearing neurons are shaped by distinct rapid and graded receptor potentials from hair cells. To date, technical difficulties in isolation of fragile posthearing neurons from the rigid bony labyrinth of the inner ear have hindered analyses of the electrical phenotype of SGNs. Therefore, we have recently developed new strategies to isolate posthearing mouse SGNs for functional analyses. Here, we describe the coarse and fine properties of Ca2+ currents, which sculpt the firing properties of posthearing SGNs. Murine SGNs express multiple Ca2+ channel currents to enable diverse functions. We have demonstrated that suppression of Ca2+ currents results in significant hyperpolarization of the resting membrane potential (rmp) of basal SGNs, suggesting that Ca2+ influx primesrmpfor excitation. In contrast, removal of external Ca2+has modest effects onrmpof apical SGNs. The blockade of Ca2+currents with a mixture of specific blockers attenuates spontaneously active SGNs. Paradoxically, different subtypes of Ca2+ currents, such as R-type currents, may activate resting outward conductances since blockage of the current results in depolarization of rmp. In keeping with whole-cell current data, single-channel records revealed multiple diverse Ca2+ channels in SGNs. Additionally, there were differential expressions of distinct Ca2+ current densities in the apicobasal contour of the adult cochlea. This report provides invaluable insights into Ca2+-dependent processes in adult SGNs.
| Original language | English |
|---|---|
| Pages (from-to) | 16314-16330 |
| Number of pages | 17 |
| Journal | Journal of Neuroscience |
| Volume | 32 |
| Issue number | 46 |
| DOIs | |
| State | Published - Nov 14 2012 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Neuroscience(all)
Cite this
Posthearing Ca2+ currents and their roles in shaping the different modes of firing of spiral ganglion neurons. / Lv, Ping; Sihn, Choong Ryoul; Wang, Wenying; Shen, Haitao; Kim, Hyo Jeong; Rocha-Sanchez, Sonia; Yamoah, Ebenezer N.
In: Journal of Neuroscience, Vol. 32, No. 46, 14.11.2012, p. 16314-16330.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Posthearing Ca2+ currents and their roles in shaping the different modes of firing of spiral ganglion neurons
AU - Lv, Ping
AU - Sihn, Choong Ryoul
AU - Wang, Wenying
AU - Shen, Haitao
AU - Kim, Hyo Jeong
AU - Rocha-Sanchez, Sonia
AU - Yamoah, Ebenezer N.
PY - 2012/11/14
Y1 - 2012/11/14
N2 - Whereas prehearing spiral ganglion neurons (SGNs) rely faithfully on outputs from spontaneously active developing hair cells, the electrical phenotypes of posthearing neurons are shaped by distinct rapid and graded receptor potentials from hair cells. To date, technical difficulties in isolation of fragile posthearing neurons from the rigid bony labyrinth of the inner ear have hindered analyses of the electrical phenotype of SGNs. Therefore, we have recently developed new strategies to isolate posthearing mouse SGNs for functional analyses. Here, we describe the coarse and fine properties of Ca2+ currents, which sculpt the firing properties of posthearing SGNs. Murine SGNs express multiple Ca2+ channel currents to enable diverse functions. We have demonstrated that suppression of Ca2+ currents results in significant hyperpolarization of the resting membrane potential (rmp) of basal SGNs, suggesting that Ca2+ influx primesrmpfor excitation. In contrast, removal of external Ca2+has modest effects onrmpof apical SGNs. The blockade of Ca2+currents with a mixture of specific blockers attenuates spontaneously active SGNs. Paradoxically, different subtypes of Ca2+ currents, such as R-type currents, may activate resting outward conductances since blockage of the current results in depolarization of rmp. In keeping with whole-cell current data, single-channel records revealed multiple diverse Ca2+ channels in SGNs. Additionally, there were differential expressions of distinct Ca2+ current densities in the apicobasal contour of the adult cochlea. This report provides invaluable insights into Ca2+-dependent processes in adult SGNs.
AB - Whereas prehearing spiral ganglion neurons (SGNs) rely faithfully on outputs from spontaneously active developing hair cells, the electrical phenotypes of posthearing neurons are shaped by distinct rapid and graded receptor potentials from hair cells. To date, technical difficulties in isolation of fragile posthearing neurons from the rigid bony labyrinth of the inner ear have hindered analyses of the electrical phenotype of SGNs. Therefore, we have recently developed new strategies to isolate posthearing mouse SGNs for functional analyses. Here, we describe the coarse and fine properties of Ca2+ currents, which sculpt the firing properties of posthearing SGNs. Murine SGNs express multiple Ca2+ channel currents to enable diverse functions. We have demonstrated that suppression of Ca2+ currents results in significant hyperpolarization of the resting membrane potential (rmp) of basal SGNs, suggesting that Ca2+ influx primesrmpfor excitation. In contrast, removal of external Ca2+has modest effects onrmpof apical SGNs. The blockade of Ca2+currents with a mixture of specific blockers attenuates spontaneously active SGNs. Paradoxically, different subtypes of Ca2+ currents, such as R-type currents, may activate resting outward conductances since blockage of the current results in depolarization of rmp. In keeping with whole-cell current data, single-channel records revealed multiple diverse Ca2+ channels in SGNs. Additionally, there were differential expressions of distinct Ca2+ current densities in the apicobasal contour of the adult cochlea. This report provides invaluable insights into Ca2+-dependent processes in adult SGNs.
UR - http://www.scopus.com/inward/record.url?scp=84869036507&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84869036507&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.2097-12.20
DO - 10.1523/JNEUROSCI.2097-12.20
M3 - Article
C2 - 23152615
AN - SCOPUS:84869036507
VL - 32
SP - 16314
EP - 16330
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 46
ER -