Voltage-gated ionic currents in an identified modulatory cell type controlling molluscan feeding. Staras, K.; Gyori, J.; and Kemenes, G. European Journal of Neuroscience, 15(1):109–119, Wiley Online Library, 2002.
Voltage-gated ionic currents in an identified modulatory cell type controlling molluscan feeding [link]Paper  doi  abstract   bibtex   
An important modulatory cell type, found in all molluscan feeding networks, was investigated using two-electrode voltage- and current-clamp methods. In the cerebral giant cells of Lymnaea, a transient inward Na+ current was identified with activation at -58 ± 2 mV. It was sensitive to tetrodotoxin only in high concentrations (≈ 50% block at 100 $\mu$M), a characteristic of Na+ channels in many molluscan neurons. A much smaller low-threshold persistent Na+ current (activation at \textless-90 mV) was also identified. Two purely voltage-sensitive outward K+ currents were also found: (i) a transient A-current type which was activated at -59 ± 4 mV and blocked by 4-aminopyridine; (ii) a sustained tetraethylammonium-sensitive delayed rectifier current which was activated at -47 ± 2 mV. There was also evidence that a third, Ca2+-activated, K+ channel made a contribution to the total outward current. No inwardly rectifying currents were found. Two Ca2+ currents were characterized: (i) a transient low-voltage (-65 ± 2 mV) activated T-type current, which was blocked in NiCl2 (2 mM) and was completely inactivated at ≈-50 mV; (ii) A sustained high voltage (-40 ± 1 mV) activated current, which was blocked in CdCl2 (100 $\mu$M) but not in $\omega$-conotoxin GVIA (10 $\mu$M), $\omega$-agatoxin IVA (500 nM) or nifedipine (10 $\mu$M). This current was enhanced in Ba2+ saline. Current-clamp experiments revealed how these different current types could define the membrane potential and firing properties of the cerebral giant cells, which are important in shaping the wide-acting modulatory influence of this neuron on the rest of the feeding network.
@article{pop00711,
abstract = {An important modulatory cell type, found in all molluscan feeding networks, was investigated using two-electrode voltage- and current-clamp methods. In the cerebral giant cells of Lymnaea, a transient inward Na+ current was identified with activation at -58 ± 2 mV. It was sensitive to tetrodotoxin only in high concentrations (≈ 50{\%} block at 100 $\mu$M), a characteristic of Na+ channels in many molluscan neurons. A much smaller low-threshold persistent Na+ current (activation at {\textless}-90 mV) was also identified. Two purely voltage-sensitive outward K+ currents were also found: (i) a transient A-current type which was activated at -59 ± 4 mV and blocked by 4-aminopyridine; (ii) a sustained tetraethylammonium-sensitive delayed rectifier current which was activated at -47 ± 2 mV. There was also evidence that a third, Ca2+-activated, K+ channel made a contribution to the total outward current. No inwardly rectifying currents were found. Two Ca2+ currents were characterized: (i) a transient low-voltage (-65 ± 2 mV) activated T-type current, which was blocked in NiCl2 (2 mM) and was completely inactivated at ≈-50 mV; (ii) A sustained high voltage (-40 ± 1 mV) activated current, which was blocked in CdCl2 (100 $\mu$M) but not in $\omega$-conotoxin GVIA (10 $\mu$M), $\omega$-agatoxin IVA (500 nM) or nifedipine (10 $\mu$M). This current was enhanced in Ba2+ saline. Current-clamp experiments revealed how these different current types could define the membrane potential and firing properties of the cerebral giant cells, which are important in shaping the wide-acting modulatory influence of this neuron on the rest of the feeding network.},
annote = {Query date: 2020-06-29 13:05:30},
author = {Staras, Kevin and Gyori, J{\'{a}}nos and Kemenes, Gy{\"{o}}rgy},
doi = {10.1046/j.0953-816x.2001.01845.x},
issn = {0953816X},
journal = {European Journal of Neuroscience},
keywords = {Cerebral giant cells,Feeding network,Lymnaea,Membrane properties,Spike generation},
number = {1},
pages = {109--119},
publisher = {Wiley Online Library},
title = {{Voltage-gated ionic currents in an identified modulatory cell type controlling molluscan feeding}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.0953-816x.2001.01845.x},
volume = {15},
year = {2002}
}
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