Phasic Transmitter Release from Tonic Neurons
نویسندگان
چکیده
Graded and prolonged presynaptic depolarizations trigger the tonic release of neurotransmitters from sensory neurons. In this issue of Neuron, Simmons reports that postsynaptic responses of locust interneuron synpapses are determined by the rate rather than the amplitude of presynaptic depolarization, suggesting a mechanism for increasing the signaling capabilities of this synapse with respect to visual processing.
منابع مشابه
Synaptic structure and transmitter release in crustacean phasic and tonic motor neurons.
The paired phasic and tonic motor neurons supplying the extensor muscle in the crayfish leg were investigated to establish whether differences in synaptic structure could account for large differences in transmitter release at the neuromuscular junctions. Nerve terminals with transmitter release that had been assessed from recordings made with a focal "macro-patch" electrode were subsequently l...
متن کاملCrustacean Phasic and Tonic Motor Neurons1
SYNOPSIS. Crustacean motor neurons subserving locomotion are specialized for the type of activity in which they normally participate. Neurons responsible for maintained activity (‘tonic’ neurons) support moderate to high frequencies of nerve impulses intermittently or continuously during locomotion, while those recruited for short-lasting rapid responses (‘phasic’ neurons) generally fire a few ...
متن کاملCalcium entry related to active zones and differences in transmitter release at phasic and tonic synapses.
Synaptic functional differentiation of crayfish phasic and tonic motor neurons is large. For one impulse, quantal release of neurotransmitter is typically 100-1000 times higher for phasic synapses. We tested the hypothesis that differences in synaptic strength are determined by differences in synaptic calcium entry. Calcium signals were measured with the injected calcium indicator dyes Calcium ...
متن کاملCalcium sensitivity of neurotransmitter release differs at phasic and tonic synapses.
The efficacy of synaptic transmission varies greatly among synaptic contacts. We have explored the origins of differences between phasic and tonic crustacean neuromuscular junctions. Synaptic boutons of a phasic motor neuron release three orders of magnitude more quanta to a single action potential and show strong depression to a train, whereas tonic synapses are nearly unresponsive to single a...
متن کاملVisible evidence for differences in synaptic effectiveness with activity-dependent vesicular uptake and release of FM1-43.
Activity-dependent uptake and release of the fluorescent probe FM1-43 were used to compare synaptic performance (rates of transmitter release and synaptic vesicle turnover) at different frequencies in phasic and tonic motor neurons innervating the crayfish leg extensor muscle and in the tonic motor neuron of the opener muscle. The phasic extensor motor neuron, which has a high quantal content o...
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ورودعنوان ژورنال:
- Neuron
دوره 35 شماره
صفحات -
تاریخ انتشار 2002