Abstract
Neuronal activity regulates brain development and synaptic plasticity through N-methyl-D-aspartate receptors (NMDARs) and calcium-dependent signaling pathways. Intracellular sodium ([Na+]i) also exerts a regulatory influence on NMDAR channel activity, and [Na+] imay, therefore, function as a signaling molecule. In an attempt to mimic the influence of neuronal activity on synaptic plasticity, we used brevetoxin-2 (PbTx-2), a voltage-gated sodium channel (VGSC) gating modifier, to manipulate [Na+]i in cerebrocortical neurons. The acute application of PbTx-2 produced concentration-dependent increments in both intracellular [Na+] and [Ca2+]. Pharmacological evaluation showed that PbTx-2-induced Ca2+ influx primarily involved VGSC activation and NMDAR-mediated entry. Additionally, PbTx-2 robustly potentiated NMDA-induced Ca2+ influx. PbTx-2-exposed neurons showed enhanced neurite outgrowth, increased dendritic arbor complexity, and increased dendritic filopodia density. The appearance of spontaneous calcium oscillations, reflecting synchronous neuronal activity, was accelerated by PbTx-2 treatment. Parallel to this response, PbTx-2 increased cerebrocortical neuron synaptic density. PbTx-2 stimulation of neurite outgrowth, dendritic arborization, and synaptogenesis all exhibited bidirectional concentration-response profiles. This profile paralleled that of NMDA, which also produced bidirectional concentration-response profiles for neurite outgrowth and synaptogenesis. These data are consistent with the hypothesis that PbTx-2-enhanced neuronal plasticity involves NMDAR-dependent signaling. Our results demonstrate that PbTx-2 mimics activity-dependent neuronal structural plasticity in cerebrocortical neurons through an increase in [Na+]i, up-regulation of NMDAR function, and engagement of downstream Ca2+-dependent signaling pathways. These data suggest that VGSC gating modifiers may represent a pharmacologic strategy to regulate neuronal plasticity through NMDAR-dependent mechanisms.
| Original language | English |
|---|---|
| Pages (from-to) | 19840-19845 |
| Number of pages | 6 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 109 |
| Issue number | 48 |
| DOIs | |
| State | Published - Nov 27 2012 |
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Bidirectional influence of sodium channel activation on NMDA receptor-dependent cerebrocortical neuron structural plasticity. / George, Joju; Baden, Daniel G.; Gerwick, William H.; Murray, Thomas F.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 109, No. 48, 27.11.2012, p. 19840-19845.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Bidirectional influence of sodium channel activation on NMDA receptor-dependent cerebrocortical neuron structural plasticity
AU - George, Joju
AU - Baden, Daniel G.
AU - Gerwick, William H.
AU - Murray, Thomas F.
PY - 2012/11/27
Y1 - 2012/11/27
N2 - Neuronal activity regulates brain development and synaptic plasticity through N-methyl-D-aspartate receptors (NMDARs) and calcium-dependent signaling pathways. Intracellular sodium ([Na+]i) also exerts a regulatory influence on NMDAR channel activity, and [Na+] imay, therefore, function as a signaling molecule. In an attempt to mimic the influence of neuronal activity on synaptic plasticity, we used brevetoxin-2 (PbTx-2), a voltage-gated sodium channel (VGSC) gating modifier, to manipulate [Na+]i in cerebrocortical neurons. The acute application of PbTx-2 produced concentration-dependent increments in both intracellular [Na+] and [Ca2+]. Pharmacological evaluation showed that PbTx-2-induced Ca2+ influx primarily involved VGSC activation and NMDAR-mediated entry. Additionally, PbTx-2 robustly potentiated NMDA-induced Ca2+ influx. PbTx-2-exposed neurons showed enhanced neurite outgrowth, increased dendritic arbor complexity, and increased dendritic filopodia density. The appearance of spontaneous calcium oscillations, reflecting synchronous neuronal activity, was accelerated by PbTx-2 treatment. Parallel to this response, PbTx-2 increased cerebrocortical neuron synaptic density. PbTx-2 stimulation of neurite outgrowth, dendritic arborization, and synaptogenesis all exhibited bidirectional concentration-response profiles. This profile paralleled that of NMDA, which also produced bidirectional concentration-response profiles for neurite outgrowth and synaptogenesis. These data are consistent with the hypothesis that PbTx-2-enhanced neuronal plasticity involves NMDAR-dependent signaling. Our results demonstrate that PbTx-2 mimics activity-dependent neuronal structural plasticity in cerebrocortical neurons through an increase in [Na+]i, up-regulation of NMDAR function, and engagement of downstream Ca2+-dependent signaling pathways. These data suggest that VGSC gating modifiers may represent a pharmacologic strategy to regulate neuronal plasticity through NMDAR-dependent mechanisms.
AB - Neuronal activity regulates brain development and synaptic plasticity through N-methyl-D-aspartate receptors (NMDARs) and calcium-dependent signaling pathways. Intracellular sodium ([Na+]i) also exerts a regulatory influence on NMDAR channel activity, and [Na+] imay, therefore, function as a signaling molecule. In an attempt to mimic the influence of neuronal activity on synaptic plasticity, we used brevetoxin-2 (PbTx-2), a voltage-gated sodium channel (VGSC) gating modifier, to manipulate [Na+]i in cerebrocortical neurons. The acute application of PbTx-2 produced concentration-dependent increments in both intracellular [Na+] and [Ca2+]. Pharmacological evaluation showed that PbTx-2-induced Ca2+ influx primarily involved VGSC activation and NMDAR-mediated entry. Additionally, PbTx-2 robustly potentiated NMDA-induced Ca2+ influx. PbTx-2-exposed neurons showed enhanced neurite outgrowth, increased dendritic arbor complexity, and increased dendritic filopodia density. The appearance of spontaneous calcium oscillations, reflecting synchronous neuronal activity, was accelerated by PbTx-2 treatment. Parallel to this response, PbTx-2 increased cerebrocortical neuron synaptic density. PbTx-2 stimulation of neurite outgrowth, dendritic arborization, and synaptogenesis all exhibited bidirectional concentration-response profiles. This profile paralleled that of NMDA, which also produced bidirectional concentration-response profiles for neurite outgrowth and synaptogenesis. These data are consistent with the hypothesis that PbTx-2-enhanced neuronal plasticity involves NMDAR-dependent signaling. Our results demonstrate that PbTx-2 mimics activity-dependent neuronal structural plasticity in cerebrocortical neurons through an increase in [Na+]i, up-regulation of NMDAR function, and engagement of downstream Ca2+-dependent signaling pathways. These data suggest that VGSC gating modifiers may represent a pharmacologic strategy to regulate neuronal plasticity through NMDAR-dependent mechanisms.
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U2 - 10.1073/pnas.1212584109
DO - 10.1073/pnas.1212584109
M3 - Article
C2 - 23150561
AN - SCOPUS:84870320064
VL - 109
SP - 19840
EP - 19845
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 48
ER -