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Functional Calcium Imaging in Developing Cortical Networks
Published on: October 22, 2011
Hyperpolarization-activated cation current contributes to spontaneous network activity in developing neocortical
Julia Klueva1, Ana D de Lima, Susanne Meis
1Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke-Universität, Magdeburg, Germany.
Neuro-Signals
|November 19, 2011
Summary
The hyperpolarization-activated cation current (I(h)) significantly contributes to spontaneous burst activity (SBA) in embryonic cortical neurons. Blocking this current reduces neuronal activity and synaptic transmission, highlighting HCN channels
Area of Science:
- Neuroscience
- Cellular Neuroscience
- Developmental Neuroscience
Background:
- Spontaneous burst activity (SBA) is crucial for developing neuronal networks.
- The mechanisms driving SBA in embryonic cortical neurons are not fully understood.
Purpose of the Study:
- To investigate the role of the hyperpolarization-activated cation current (I(h)) in SBA of embryonic mouse cortical cultures.
- To identify the specific HCN channel isoforms involved.
Main Methods:
- Patch-clamp recordings in vitro to measure I(h) in GABAergic interneurons (L-INs) and principal neurons (PNs).
- Pharmacological blockade of I(h) using ZD7288 and Cs⁺.
- Immunocytochemistry and Western blot to detect HCN channel expression.
- Calcium imaging to assess activity-driven transients.
Main Results:
- I(h) current was detected in L-INs and PNs from DIV 5.
- I(h) blockers abolished voltage sag and rebound depolarization, hyperpolarized neurons, and increased input resistance.
- I(h) blockade reduced SBA, Ca²⁺ transients, and miniature GABAergic postsynaptic current frequency and amplitude.
- HCN1 and HCN2 were identified as the predominant HCN channel isoforms.
Conclusions:
- The hyperpolarization-activated cation current (I(h)) plays a significant role in maintaining spontaneous burst activity in embryonic cortical cultures.
- HCN channels, particularly HCN1 and HCN2, are critical for SBA and synaptic function in developing cortical networks.
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