Related Experiment Video
Updated: May 31, 2026

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration
Published on: July 31, 2013
Tonic excitation or inhibition is set by GABA(A) conductance in hippocampal interneurons
Inseon Song1, Leonid Savtchenko, Alexey Semyanov
1RIKEN Brain Science Institute (BSI), Wako, Saitama 351-0198, Japan.
Abstract:
Inhibition is a physiological process that decreases the probability of a neuron generating an action potential. The two main mechanisms that have been proposed for inhibition are hyperpolarization and shunting. Shunting results from increased membrane conductance, and it reduces the neuron-firing probability. Here we show that ambient GABA, the main inhibitory neurotransmitter in the brain, can excite adult hippocampal interneurons. In these cells, the GABA(A) current reversal potential is depolarizing, making baseline tonic GABA(A) conductance excitatory. Increasing the tonic conductance enhances shunting-mediated inhibition, which eventually overpowers the excitation. Such a biphasic change in interneuron firing leads to corresponding changes in the GABA(A)-mediated synaptic signalling. The described phenomenon suggests that the excitatory or inhibitory actions of the current are set not only by the reversal potential, but also by the conductance.
More Related Videos
Related Concept Videos
Excitatory and Inhibitory Effects of Neurotransmitters
Ligand-Gated Ion Channel Receptor: Gating Mechanism
The Role of Ion Channels in Neuronal Computation
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.
Integration of Synaptic Events
G-Protein Gated Ion Channels
Sensory organs,...
Antiepileptic Drugs: GABAergic Pathway Potentiators
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for their...

