TY - JOUR
T1 - Dopaminergic Modulation of Axon Initial Segment Calcium Channels Regulates Action Potential Initiation
AU - Bender, Kevin J.
AU - Ford, Christopher P.
AU - Trussell, Laurence O.
N1 - Funding Information:
We are grateful to J. Trapani, J. Deignan, and members of the Trussell and Williams labs for comments, and to J. Williams for reading the manuscript. We thank D. Grandy and J. Williams for knockout and transgenic mice, and to A. Truitt, M. Grandy, K. Suchland, A. Matsui, and N. Quillinan for genotyping expertise. This research was supported by NIH grants K99DC011080 (K.J.B.), K99DA026417 (C.P.F.), and NS028901 (L.O.T.).
PY - 2010/11/4
Y1 - 2010/11/4
N2 - Action potentials initiate in the axon initial segment (AIS), a specialized compartment enriched with Na+ and K+ channels. Recently, we found that T- and R-type Ca2+ channels are concentrated in the AIS, where they contribute to local subthreshold membrane depolarization and thereby influence action potential initiation. While periods of high-frequency activity can alter availability of AIS voltage-gated channels, mechanisms for long-term modulation of AIS channel function remain unknown. Here, we examined the regulatory pathways that control AIS Ca2+ channel activity in brainstem interneurons. T-type Ca2+ channels were downregulated by dopamine receptor activation acting via protein kinase C, which in turn reduced neuronal output. These effects occurred without altering AIS Na+ or somatodendritic T-type channel activity and could be mediated by endogenous dopamine sources present in the auditory brainstem. This pathway represents a new mechanism to inhibit neurons by specifically regulating Ca2+ channels directly involved in action potential initiation.
AB - Action potentials initiate in the axon initial segment (AIS), a specialized compartment enriched with Na+ and K+ channels. Recently, we found that T- and R-type Ca2+ channels are concentrated in the AIS, where they contribute to local subthreshold membrane depolarization and thereby influence action potential initiation. While periods of high-frequency activity can alter availability of AIS voltage-gated channels, mechanisms for long-term modulation of AIS channel function remain unknown. Here, we examined the regulatory pathways that control AIS Ca2+ channel activity in brainstem interneurons. T-type Ca2+ channels were downregulated by dopamine receptor activation acting via protein kinase C, which in turn reduced neuronal output. These effects occurred without altering AIS Na+ or somatodendritic T-type channel activity and could be mediated by endogenous dopamine sources present in the auditory brainstem. This pathway represents a new mechanism to inhibit neurons by specifically regulating Ca2+ channels directly involved in action potential initiation.
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U2 - 10.1016/j.neuron.2010.09.026
DO - 10.1016/j.neuron.2010.09.026
M3 - Article
C2 - 21040850
AN - SCOPUS:78049298614
SN - 0896-6273
VL - 68
SP - 500
EP - 511
JO - Neuron
JF - Neuron
IS - 3
ER -