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Updated: Jul 18, 2026
14:37
Whole-cell Patch-clamp Recordings from Morphologically- and Neurochemically-identified Hippocampal Interneurons
Published on: September 30, 2014
A blocker-resistant, fast-decaying, intermediate-threshold calcium current in palaeocortical pyramidal neurons
J Magistretti1, S Brevi, M de Curtis
1Laboratorio di Biofisica e Neurofisiologia dei Sistemi Corticali, Dipartimento di Neurofisiologia Sperimentale, Istituto Nazionale Neurologico 'Carlo Besta', Milano, Italy.
The European Journal of Neuroscience
|August 18, 2000
Summary
Researchers identified a novel calcium current (IRfi) in piriform cortex neurons. This current exhibits fast inactivation and resistance to common blockers, distinguishing it from known calcium channels.
Area of Science:
- Neuroscience
- Electrophysiology
- Molecular Biology
Background:
- Piriform cortex (PC) neurons exhibit complex calcium (Ca2+) currents.
- Understanding these currents is crucial for deciphering neuronal function and excitability.
Purpose of the Study:
- To characterize a distinct Ca2+ current in guinea-pig piriform cortex layer II neurons.
- To differentiate this current from known high-voltage-activated Ca2+ channels and T-type currents.
Main Methods:
- Whole-cell patch-clamp recordings were performed on acutely dissociated guinea-pig PC layer II neurons.
- Barium (Ba2+) was used as the charge carrier to record Ca2+ currents (IBas).
- Pharmacological blockers (L-, N-, P/Q-type) and Ni2+ were used to isolate and characterize current properties.
Main Results:
- A subpopulation of neurons (approx. 22%) displayed a fast-inactivating Ba2+ current (IBa) resistant to L-, N-, and P/Q-type Ca2+-channel blockers.
- This isolated current, named IRfi, showed bi-exponential inactivation (approx. 20 ms and 100 ms) and an intermediate activation threshold.
- IRfi amplitude was minimally affected by extracellular Ca2+ substitution and was inhibited by Ni2+ (50 microM).
Conclusions:
- IRfi is a distinct Ca2+ current characterized by fast inactivation, intermediate activation, and resistance to organic blockers.
- IRfi differs significantly from classical high-voltage-activated and T-type Ca2+ currents.
- The properties of IRfi suggest a potential similarity to Ca2+ currents mediated by alpha1E-type channel subunits.
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