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Low-voltage activated calcium currents increase in basal forebrain neurons from aged rats
1Department of Medical Pharmacology and Toxicology, College of Medicine, Texas A&M University, College Station 77843, USA.
Journal of Neurophysiology
|August 1, 1995
Summary
Aging Fischer 344 rats show enhanced low-voltage-activated (LVA) calcium currents in medial septum/diagonal band neurons. This suggests retained or improved rhythmic firing and potential changes in calcium homeostasis in aged neurons.
Area of Science:
- Neuroscience
- Aging Research
- Electrophysiology
Background:
- The medial septum and nucleus of the diagonal band (MS/nDB) are crucial for cognitive functions.
- Neuronal excitability and calcium signaling are known to change with age.
- Low-voltage-activated (LVA) calcium channels play a key role in neuronal firing patterns.
Purpose of the Study:
- To investigate age-related changes in LVA calcium currents in MS/nDB neurons.
- To compare the properties of LVA currents in young and aged Fischer 344 rats.
- To understand the implications of these changes for neuronal function and calcium homeostasis.
Main Methods:
- Whole-cell patch-clamp recordings were performed on acutely dissociated MS/nDB neurons.
- Barium (Ba2+) was used as the charge carrier for calcium (Ca2+) currents.
- Neurons from young (1-3 months) and aged (24-26 months) Fischer 344 rats were analyzed.
Main Results:
- Most neurons in both age groups exhibited LVA currents (84% young, 87% aged).
- Aged neurons were significantly smaller in cell capacitance than young neurons.
- LVA current density was significantly increased in aged neurons compared to young neurons, particularly at negative potentials.
Conclusions:
- MS/nDB neurons maintain robust LVA currents into old age.
- Increased LVA current density in aged rats suggests retained or enhanced rhythmic/burst firing capabilities.
- The observed increase in LVA currents may impact intracellular calcium levels and homeostasis in aging neurons.