Receptors with opposing functions are in postsynaptic microdomains under one presynaptic terminal
G Tsen1, B Williams, P Allaire
1Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave., Boston, Massachusetts 02111, USA.
Nature Neuroscience
|January 29, 2000
Summary
This study reveals that nicotinic acetylcholine receptors and glycine receptors coexist on chick neurons, challenging established principles. This finding offers a novel mechanism for regulating synaptic activity in the nervous system.
Area of Science:
- Neuroscience
- Synaptic transmission
- Molecular biology
Background:
- Fast excitatory synaptic transmission in vertebrate autonomic ganglia relies on postsynaptic nicotinic acetylcholine receptors (nAChRs).
- Dale's principle suggests a neuron releases only one type of neurotransmitter.
Purpose of the Study:
- To investigate receptor microheterogeneity at synapses in chick parasympathetic ciliary ganglion neurons.
- To explore the functional implications of co-localized receptors with potentially opposing roles.
Main Methods:
- Utilized [3H]glycine loading via glycine transporter-1 (GlyT-1) in presynaptic terminals.
- Measured depolarization-evoked [3H]glycine release and its modulation by sarcosine.
- Assessed the effect of glycine on nAChR-mediated ganglionic synaptic transmission.
Main Results:
- Demonstrated separate, proximal clusters of nAChRs and glycine receptors under single presynaptic terminals.
- Showed calcium-independent release of [3H]glycine from cholinergic terminals, inhibited by sarcosine.
- Observed attenuation of nAChR-mediated transmission by glycine.
Conclusions:
- The coexistence of distinct receptor clusters with opposing functions under one terminal challenges Dale's principle.
- This microheterogeneity presents a novel mechanism for modulating synaptic activity in vivo.
- Findings suggest a more complex regulation of autonomic ganglionic transmission than previously understood.
More Related Videos
Related Concept Videos
01:12Synaptic Signaling
Neurons communicate at synapses, or junctions, to excite or inhibit the activity of other neurons or target cells, such as muscles. Synapses may be chemical or electrical.
02:47The Synapse
Neurons communicate with one another by passing on their electrical signals to other neurons. A synapse is the location where two neurons meet to exchange signals. At the synapse, the neuron that sends the signal is called the presynaptic cell, while the neuron that receives the message is called the postsynaptic cell. Note that most neurons can be both presynaptic and postsynaptic, as they both transmit and receive information.
01:09Synaptic Signaling
Neurons communicate at synapses, or junctions, to excite or inhibit the activity of other neurons or target cells, such as muscles. Synapses may be chemical or electrical.
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
01:29Excitatory and Inhibitory Effects of Neurotransmitters
When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of specific...
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...
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...
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...
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...