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Isolation of Sensory Neurons of Aplysia californica for Patch Clamp Recordings of Glutamatergic Currents
Published on: July 10, 2013
Chloride distribution in Aplysia neurones
1Laboratoire de Neurobiologie, Ecole Normale Supérieure, 46, rue d'Ulm, Paris 75005, France.
The Journal of Physiology
|April 1, 1976
Summary
This study investigated intracellular chloride concentration and membrane potential in Aplysia neurons. Findings suggest chloride conductance varies with conditions and active transport may influence chloride levels.
Area of Science:
- Neuroscience
- Cell Physiology
- Ion Transport
Background:
- Intracellular chloride concentration (Cl(i)) and membrane potential (E(m)) are critical for neuronal function.
- Understanding chloride conductance and active transport is key to deciphering neuronal excitability.
Purpose of the Study:
- To determine the chloride (Cl(-)) conductance of Aplysia medial pleural neurons.
- To investigate the potential for active Cl(-) transport across the neuronal membrane.
Main Methods:
- Measurement of intracellular Cl(-) concentration (Cl(i)) and membrane potential (E(m)) in Aplysia medial pleural neurons.
- Experimental manipulation of external ion concentrations (K(+), Cl(-), Ca(2+)) and application of specific ions (TEA, procaine, NH(4)(+)).
- Experiments conducted on intact neurons and isolated cell somas.
Main Results:
- Chloride conductance varied significantly with experimental conditions.
- High chloride conductance was observed in high K(o) or very low Cl(o), attributed to synaptic transmitter release.
- Tetraethylammonium (TEA) and procaine induced depolarization and a decrease in Cl(i) against passive driving force, suggesting active transport.
Conclusions:
- Neuronal chloride conductance is condition-dependent and influenced by synaptic activity.
- Evidence suggests the presence of active chloride transport mechanisms in Aplysia neurons.
- Anomalous chloride movements may explain discrepancies between E(Cl) and E(m) under normal conditions.
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01:41Action Potentials
Overview
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
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01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
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A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.