Differential expression of voltage-gated potassium channel genes in auditory nuclei of the mouse brainstem

Grigg, John J.; Brew, Helen M.; Tempel, Bruce L.

doi:10.1016/s0378-5955(99)00187-2

Cited by 121 publications

(125 citation statements)

References 40 publications

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“…The voltage sensitivity, kinetics, and dendrotoxin sensitivity of I K(LVA) in MSO principal cells in many respects resembles that of other brainstem auditory neurons concerned with maintaining the precise timing of excitatory inputs, such as bushy and octopus cells of the VCN, and principal cells of the MNTB (Manis and Marx, 1991;Rathouz and Trussell, 1998;Bal and Oertel, 2001;Dodson et al, 2002;Rothman and Manis, 2003). In situ hybridization and immunocytochemical analyses also reveal that the Kv1.1 subunit is prominently expressed in these brainstem auditory nuclei (Grigg et al, 2000;Dodson et al, 2002;Lu et al, 2004). In the present study, we observed an increase in the amount of I K(LVA) blocked by DTX-K between P14 and P21 (76 to 91% block), possibly reflecting an increase in the proportion of channels containing Kv1.1.…”

Section: Properties and Developmental Regulation Of I K(lva) In Mso Pmentioning

confidence: 93%

Posthearing Developmental Refinement of Temporal Processing in Principal Neurons of the Medial Superior Olive

Scott¹,

Mathews²,

Golding³

2005

J. Neurosci.

161

229

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In mammals, principal neurons of the medial superior olive (MSO) exhibit biophysical specializations that enable them to detect soundlocalization cues with microsecond precision. In the present study, we used whole-cell patch recordings to examine the development of the intrinsic electrical properties of these neurons in brainstem slices from postnatal day 14 (P14) to P38 gerbils. In the week after hearing onset (P14 -P21), we observed dramatic reductions in somatic EPSP duration, input resistance, and membrane time constant. Surprisingly, somatically recorded action potentials also dramatically declined in amplitude over a similar period (38 Ϯ 3 to 17 Ϯ 2 mV; ϭ 5.2 d). Simultaneous somatic and dendritic patch recordings revealed that these action potentials were initiated in the axon, which primarily emerged from the soma. In older gerbils, the rapid speed of membrane voltage changes and the attenuation of action potential amplitudes were mediated extensively by low voltage-activated potassium channels containing the Kv1.1 subunit. In addition, whole-cell voltage-clamp recordings revealed that these potassium channels increase nearly fourfold from P14 to P23 and are thus a major component of developmental changes in excitability. Finally, the electrophysiological features of principal neurons of the medial nucleus of the trapezoid body did not change after P14, indicating that posthearing regulation of intrinsic membrane properties is not a general feature of all time-coding auditory neurons. We suggest that the striking electrical segregation of the axon from the soma and dendrites of MSO principal neurons minimizes spike-induced distortion of synaptic potentials and thus preserves the accuracy of binaural comparisons.

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Section: Properties and Developmental Regulation Of I K(lva) In Mso Pmentioning

confidence: 93%

Posthearing Developmental Refinement of Temporal Processing in Principal Neurons of the Medial Superior Olive

Scott¹,

Mathews²,

Golding³

2005

J. Neurosci.

161

229

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“…We examined how potassium channel activation influenced the threshold conductance, focusing on K V 1 and K V 3 channels, which are likely to be activated in BCs by larger APs (Manis and Marx, 1991;Grigg et al, 2000). ␣-Dendrotoxin (DTX, 50 nM), which blocks K V 1 channels, significantly affected firing of BCs in response to current injection ( Fig.…”

Section: Na Channel Model and Dynamic Clampmentioning

confidence: 99%

Low Somatic Sodium Conductance Enhances Action Potential Precision in Time-Coding Auditory Neurons

Yang¹,

Ramamurthy

Neef

et al. 2016

J. Neurosci.

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Auditory nerve fibers encode sounds in the precise timing of action potentials (APs), which is used for such computations as sound localization. Timing information is relayed through several cell types in the auditory brainstem that share an unusual property: their APs are not overshooting, suggesting that the cells have very low somatic sodium conductance (g Na ). However, it is not clear how g Na influences temporal precision. We addressed this by comparing bushy cells (BCs) in the mouse cochlear nucleus with T-stellate cells (SCs), which do have normal overshooting APs. BCs play a central role in both relaying and refining precise timing information from the auditory nerve, whereas SCs discard precise timing information and encode the envelope of sound amplitude. Nucleated-patch recording at nearphysiological temperature indicated that the Na current density was 62% lower in BCs, and the voltage dependence of g Na inactivation was 13 mV hyperpolarized compared with SCs. We endowed BCs with SC-like g Na using two-electrode dynamic clamp and found that synaptic activity at physiologically relevant rates elicited APs with significantly lower probability, through increased activation of delayed rectifier channels. In addition, for two near-simultaneous synaptic inputs, the window of coincidence detection widened significantly with increasing g Na , indicating that refinement of temporal information by BCs is degraded by g Na . Thus, reduced somatic g Na appears to be an adaption for enhancing fidelity and precision in time-coding neurons.

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“…Both low-threshold (I LTK ) and high-threshold (I HTK ) potassium channels, however, are present in the MSO and the NL (Smith, 1995;Grigg et al, 2000). To test the robustness of the model, we added potassium channels and a hyperpolarization-activated inward current (I h ) to the soma with identical parameters to those on the axon.…”

Section: Somatic Potassium Channelsmentioning

confidence: 99%

A Model for Interaural Time Difference Sensitivity in the Medial Superior Olive: Interaction of Excitatory and Inhibitory Synaptic Inputs, Channel Dynamics, and Cellular Morphology

2005

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Differential expression of voltage-gated potassium channel genes in auditory nuclei of the mouse brainstem

Cited by 121 publications

References 40 publications

Posthearing Developmental Refinement of Temporal Processing in Principal Neurons of the Medial Superior Olive

Posthearing Developmental Refinement of Temporal Processing in Principal Neurons of the Medial Superior Olive

Low Somatic Sodium Conductance Enhances Action Potential Precision in Time-Coding Auditory Neurons

A Model for Interaural Time Difference Sensitivity in the Medial Superior Olive: Interaction of Excitatory and Inhibitory Synaptic Inputs, Channel Dynamics, and Cellular Morphology

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