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Aging changes in voltage-gated calcium currents in hippocampal CA1 neurons
L W Campbell1, S Y Hao, O Thibault
1Department of Pharmacology, College of Medicine, University of Kentucky, Lexington 40536, USA.
Summary
Aging increases calcium currents in rat hippocampal CA1 neurons, possibly due to greater channel activity, not reduced inactivation. This elevated calcium influx may impair function and increase neurotoxicity susceptibility.
Area of Science:
- Neuroscience
- Aging Research
- Cellular Electrophysiology
Background:
- Previous studies noted aging-related increases in calcium potentials in rat hippocampal CA1 neurons.
- These changes suggested altered calcium influx or potassium currents with aging.
Purpose of the Study:
- To investigate the basis of altered calcium potentials in aging CA1 neurons.
- To determine if aging affects calcium influx through voltage-gated calcium channels.
Main Methods:
- Whole-cell voltage-clamp recordings were performed on CA1 neurons from adult and aged rats.
- High-threshold calcium (Ca) and barium (Ba) currents were analyzed.
- Nimodipine block was used to assess L-type calcium currents.
Main Results:
- Aging increased high-threshold Ca and Ba currents, particularly the slowly inactivating late current.
- Neuron input resistance did not differ between age groups.
- Calcium current inactivation was not reduced in aged neurons; nimodipine-sensitive current was greater, indicating increased L-type currents.
Conclusions:
- Whole-cell calcium currents are elevated in aged CA1 neurons due to increased channel activity, not reduced inactivation.
- Increased calcium influx with aging may contribute to impaired neuronal function and heightened neurotoxicity susceptibility.