Related Experiment Video
Updated: Feb 21, 2026
07:16
Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
14.3K
Tonically Active α5GABAA Receptors Reduce Motoneuron Excitability and Decrease the Monosynaptic Reflex
Martha Canto-Bustos1, Emanuel Loeza-Alcocer2, Carlos A Cuellar3
1Department of Neuroscience, Center for the Neural Basis of Cognition, University of PittsburghPittsburgh, PA, United States.
Frontiers in Cellular Neuroscience
|October 4, 2017
Summary
Extrasynaptic alpha5 subunit-containing GABAA receptors in turtle motoneurons reduce neuronal excitability and depress reflexes. These findings suggest a significant role for these receptors in regulating motor control.
Area of Science:
- Neuroscience
- Motor Control
- Cellular Physiology
Background:
- Motoneurons, the final common pathway of the Central Nervous System (CNS), precisely control skeletal muscle activity.
- Extrasynaptic GABAA receptors are crucial for regulating neuronal excitability but remain poorly understood.
- The role of α5 subunit-containing GABAA receptors in motoneurons is not well-established.
Purpose of the Study:
- To investigate the presence and function of extrasynaptic α5 subunit-containing GABAA receptors in turtle motoneurons.
- To determine the impact of these receptors on motoneuron excitability and synaptic input.
- To elucidate the physiological relevance of α5GABAA receptors in motor control.
Main Methods:
- Localization of extrasynaptic α5 subunit-containing GABAA receptors in choline acetyltransferase (ChAT)-positive motoneurons.
- Electrophysiological recordings to assess the effects of ambient GABA on motoneuron membrane properties.
- Investigation of the impact of α5GABAA receptor activation on synaptic excitatory inputs and monosynaptic reflexes (MSR).
Main Results:
- Extrasynaptic α5 subunit-containing GABAA receptors were confirmed to be expressed in turtle motoneurons.
- Activation of these receptors by ambient GABA produced a tonic inhibitory current (shunt), reducing membrane resistance.
- This tonic shunting affected action potential firing properties and depressed monosynaptic reflexes by shunting synaptic excitatory inputs.
Conclusions:
- Extrasynaptic α5GABAA receptors are functionally expressed in turtle motoneurons.
- These receptors contribute to the regulation of motoneuron excitability and synaptic integration.
- The findings suggest a significant physiological role for α5GABAA receptors in motor control mechanisms.
More Related Videos
Related Concept Videos
01:17Nondepolarizing (Competitive) Neuromuscular Blockers: Mechanism of Action
3.1K
Nondepolarizing neuromuscular blockers induce paralysis by competitively blocking nicotinic acetylcholine receptors at the muscle end plate. Examples include pancuronium, mivacurium, vecuronium, and rocuronium. These quaternary ammonium derivatives are administered intravenously, are poorly absorbed, and are excreted via the kidneys.
Competitive antagonists prevent acetylcholine from binding to its receptor, inhibiting membrane depolarization. Without conformational changes or intrinsic...
Competitive antagonists prevent acetylcholine from binding to its receptor, inhibiting membrane depolarization. Without conformational changes or intrinsic...
3.1K
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
4.3K
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
4.3K
01:26Chemical Synapses
12.1K
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...
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...
12.1K
01:26Chemical Synapses
4.8K
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...
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...
4.8K
01:29Neuromuscular Junction And Blockade
5.2K
The site of chemical communication between a motor neuron and a muscle fiber is called the neuromuscular junction (NMJ). The end of the motor neuron at the NMJ divides into a cluster of synaptic end bulbs. The cytoplasm of these bulbs consists of synaptic vesicles enclosing acetylcholine molecules, the principal neurotransmitter released at the NMJ. The region opposite the synaptic bulb that ends in the muscle fiber is called the motor end plate, which has acetylcholine receptors. Within the...
5.2K
01:21G-Protein Gated Ion Channels
5.9K
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
Sensory...
5.9K