Comparison of Effects of Various Types of NA and 5‐HT Agonists on Transmission from Group II Muscle Afferents in the Cat

@article{Bras1990ComparisonOE,
  title={Comparison of Effects of Various Types of NA and 5‐HT Agonists on Transmission from Group II Muscle Afferents in the Cat},
  author={H{\'e}l{\`e}ne Bras and Elzbieta Jankowska and Brian R. Noga and Bengt Skoog},
  journal={European Journal of Neuroscience},
  year={1990},
  volume={2}
}
A number of noradrenaline and serotonin agonists were tested to investigate which of them replicate the depressive actions of monoamines on transmission from group II muscle afferents in the cat spinal cord. The agonists were applied ionophoretically at the two sites at which maximal monosynaptic focal field potentials are evoked from group II afferents—in the intermediate zone and the dorsal horn of the 4th and 5th lumbar segments. Their effects were estimated from changes in the amplitude of… 
Effects of Monoamines on Transmission from Group II Muscle Afferents in Sacral Segments in the Cat
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Data suggest that transmission from group II muscle spindle afferents in the sacral segments is under control of serotonin releasing neurons, as in the dorsal horn of midlumbar segments, but leave open the question of the similarities or differences in the mechanisms (pre‐and/or postsynaptic) of this control.
Effects of monoamines on interneurons in four spinal reflex pathways from group I and/or group II muscle afferents
TLDR
Results of this study lead to the conclusions that modulation of synaptic actions of muscle spindle and tendon organ afferents on spinal interneurons by 5‐HT and NA is related to both the type of the afferent and the functionaltype of the interneuron.
Differential presynaptic inhibition of actions of group II afferents in di‐ and polysynaptic pathways to feline motoneurones
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The results of this study lead to the conclusion that strong presynaptic inhibition of transmission to intermediate zone interneurones allows a selective depression of disynaptic actions of group II muscle afferents on α‐ and γ‐motoneurones, mediated by these interneURones, and favours polysynapticactions of these afferentS.
Modulatory Effects of α1-, α2-, and β-Receptor Agonists on Feline Spinal Interneurons with Monosynaptic Input from Group I Muscle Afferents
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The findings lead to the conclusion that beneficial antispastic effects of clonidine and tizanidine in humans are unlikely to be associated with an enhancement of the actions of Ia- and Ia/Ib-inhibitory interneurons, and the findings support previous proposals that these compounds exert their antispastics actions via effects on other neuronal populations.
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TLDR
It is concluded that noradrenergic descending tract neurones contribute to the depression of transmission from group II afferents to spinal interneurones and that such noradRenergic neurones are activated by stimuli applied within as well as outside their nuclei.
Role of serotonin1A receptors on the modulation of rat spinal mono-synaptic reflexes in vitro
TLDR
The results are consistent with an intervention of 5-HT(1A) receptors in the modulation of non-nociceptive reflexes but do not support a prominent role for this receptor inThe modulation of nociception reflexes.
Modulation of Responses of Four Types of Feline Ascending Tract Neurons by Serotonin and Noradrenaline
TLDR
The results indicate that transfer of information from skin and group II muscle afferents to supraspinal centres may be gated by descending monoaminergic pathways in a highly differentiated manner, and is adjusted to the requirements of various behavioural situations.
Spinal 5‐HT‐receptors and tonic modulation of transmission through a withdrawal reflex pathway in the decerebrated rabbit
TLDR
5‐HT tonically inhibits transmission between sural nerve afferents and gastrocnemius motoneurones by an action at spinal 5‐HT1A‐receptors, consistent with the idea that, in the decerebrated rabbit, 5‐ HT released from descending axons has multiple roles in controlling transmission through the sural‐gastrocnenemius medialis reflex pathway.
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