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Calcium currents in retrogradely labeled pyramidal cells from rat sensorimotor cortex.
1Department of Anatomy and Neurobiology, University of Tennessee, Memphis, Tennessee 38163, USA.
Journal of Neurophysiology
|April 12, 2000
Summary
Variability in calcium (Ca(2+)) currents in brain cells stems from recording from distinct neuronal populations. Different cell types show unique calcium current profiles, explaining observed cell-to-cell differences.
Area of Science:
- Neuroscience
- Cellular Electrophysiology
- Molecular Biology
Background:
- Cortical pyramidal cells exhibit variable calcium (Ca(2+)) currents and neurotransmitter modulation.
- Previous studies noted cell-to-cell variability in the contribution of different Ca(2+) current types.
Purpose of the Study:
- To test the hypothesis that recording from multiple pyramidal cell populations is a major source of observed variability.
- To investigate differences in Ca(2+) current composition among distinct neuronal projection types.
Main Methods:
- Whole-cell patch-clamp technique applied to dissociated corticocortical, corticostriatal, and corticotectal pyramidal cells.
- Quantification of L-, P-, and N-type Ca(2+) currents in identified cell populations.
Main Results:
- Significant differences were found in the mean percentage of L-, P-, and N-type Ca(2+) currents between the three cell types.
- N- and P-type currents showed a narrower range of expression in corticostriatal and corticotectal cells compared to corticocortical cells.
- Variance in N- and P-type currents differed significantly across cell types.
Conclusions:
- Recording from multiple neocortical pyramidal cell populations is a significant source of variability in Ca(2+) current proportions.
- Neuronal projection targets influence the specific types and proportions of Ca(2+) currents expressed.