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Updated: Aug 7, 2026
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Functional Calcium Imaging in Developing Cortical Networks
Published on: October 22, 2011
Voltage-dependent calcium channels from brain incorporated into planar lipid bilayers
Nature
|March 1, 1984
Summary
This study investigated voltage-dependent calcium channels from rat brain. Findings reveal that the type of divalent cation influences both channel conductance and open times, with barium showing the shortest mean open times.
Area of Science:
- Neuroscience
- Biophysics
- Cell Physiology
Background:
- Physiological processes like neurotransmitter release and muscle contraction depend on intracellular calcium ion (Ca2+) levels.
- Cytoplasmic Ca2+ levels are regulated by Ca2+ influx through voltage-dependent channels selective for Ca2+, Ba2+, and Sr2+ ions.
Purpose of the Study:
- To measure and characterize the properties of single, voltage-dependent calcium channels from rat brain.
- To investigate the effects of different divalent cations and known blockers on channel activity.
Main Methods:
- Incorporation of single voltage-dependent calcium channels from rat brain into planar lipid bilayers.
- Measurement of ion currents through these channels under varying voltage conditions.
- Application of divalent cations (Ca2+, Ba2+, Sr2+) and channel blockers (lanthanum, cadmium) to assess their impact on channel function.
Main Results:
- Channel gating demonstrated voltage-dependence, with depolarization increasing open times and decreasing closed times.
- Channels exhibited selectivity for divalent cations over monovalent ions.
- Lanthanum and cadmium reduced single-channel conductance in a concentration-dependent manner.
- The type of divalent cation significantly affected both single-channel conductance and mean open times, with barium yielding the shortest open times.
Conclusions:
- Voltage-dependent calcium channels from rat brain exhibit distinct gating properties and ion selectivity.
- Divalent cation identity is a critical determinant of both conductance and gating kinetics, challenging previous assumptions.
- These findings provide insights into the molecular mechanisms underlying calcium channel function and regulation.
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