Enhancement of bistability in spinal motoneurons in vivo by the noradrenergic alpha1 agonist methoxamine.

@article{Lee1999EnhancementOB,
  title={Enhancement of bistability in spinal motoneurons in vivo by the noradrenergic alpha1 agonist methoxamine.},
  author={R H Lee and Charles J. Heckman},
  journal={Journal of neurophysiology},
  year={1999},
  volume={81 5},
  pages={
          2164-74
        }
}
Enhancement of bistability in spinal motoneurons in vivo by the noradrenergic alpha1 agonist methoxamine. Like many types of motoneurons, spinal motoneurons in the adult mammal can exhibit bistable behavior. This means that short periods of excitatory input can initiate long periods of self-sustained firing and that equally short periods of inhibition can return the cell to the quiescent state. Usually, the presence of one of the monoamines (either serotonin or norepinephrine) is required for… 
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Persistent Inward Currents in Spinal Motoneurons and Their Influence on Human Motoneuron Firing Patterns
TLDR
PIC effects have been detected in motoneuron firing patterns in human subjects and, hence, PICs are likely a fundamental component of normal motor output.
Amphetamine increases persistent inward currents in human motoneurons estimated from paired motor-unit activity.
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The findings suggest that the endogenous facilitation of PICs from brain stem derived norepinephrine plays an important role in modulating human motoneuron excitability, readying motoneurons for rapid and sustained activity during periods of high arousal such as stress or fear.
Role of motoneurons in the generation of muscle spasms after spinal cord injury.
TLDR
The results suggest that the slow spontaneous firing commonly observed in chronic spinal injury likely occurs without appreciable synaptic noise and is likely driven to a substantial degree by PICs intrinsic to the motoneuron because it is self-sustained and very regular.
Reconfiguration of the electrical properties of motoneurons to match the diverse demands of motor behavior.
TLDR
It is proposed that the interactions of these inputs can induce three different states in motoneurons: integration, variable gain amplification, and oscillation, and it is suggested that these states are matched to the following motor behaviors: posture, volitional movements, and locomotion.
Active dendritic integration of inhibitory synaptic inputs in vivo.
TLDR
Results demonstrate that inhibition from local spinal circuits can oppose the facilitation of dendritic PICs by descending monoaminergic inputs, and nearly linear integration of synaptic inhibition may occur in these highly active dendrites.
Adjustable Amplification of Synaptic Input in the Dendrites of Spinal Motoneurons In Vivo
TLDR
The dendritic amplification with moderate or strong neuromodulatory drive was estimated to be large enough to allow the motoneurons innervating slow muscle fibers to be driven to their maximum force levels by remarkably small synaptic inputs.
Spinal and supraspinal functions of noradrenaline in the frog embryo: consequences for motor behaviour
TLDR
It is reported that exogenous NA application can facilitate two completely different fictive behaviours in embryos of the common frog Rana temporaria, depending on whether spinal networks are connected to supraspinal centres.
Intrinsic excitability of human motoneurons in biceps brachii versus triceps brachii.
TLDR
It is concluded that human elbow flexor and extensor motor units exhibit differences in intrinsic excitability, contributing to different neural motor control strategies between muscle groups.
Postnatal development of persistent inward currents in rat XII motoneurons and their modulation by serotonin, muscarine and noradrenaline
TLDR
Recordings from rat XII motoneurons in brain slices indicate that PIC amplitude increases ∼50% between 1 and 23 days of age, when potentiation of the PIC by 5HT2, muscarinic, or α1 noradrenergic agonists peaks at <50%, manyfold lower than the potentiation observed in spinal mot oneurons.
Bistable behavior originating in the axon of a crustacean motor neuron.
TLDR
The results suggest that bistable behavior in a motor neuron can originate in the axon and may not require the action of a locally released neuromodulator.
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References

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TLDR
The low thresholds of fully bistable cells mean they will be readily recruited in low force tasks like posture, where their prolonged self-sustained firing would be advantageous.
Bistability in spinal motoneurons in vivo: systematic variations in persistent inward currents.
TLDR
It was found that self-sustained firing was persistent for long periods only in motoneurons with low rheobases and slow axonal conduction velocities, and IPIC accounted for the main differences in the F-I behavior seen between fully and partially bistable cells.
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TLDR
It was found that short‐lasting depolarizing current pulses through the recording microelectrode could trigger a self‐sustained firing in the motoneurone provided that the bias current was kept within certain limits and HyperpolarizingCurrent pulses terminated the firing.
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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