Effects of serotonin on dorsal horn dorsal spinocerebellar tract neurons

Jankowska, E.; Krutki, Piotr; Läckberg, Z. Szabo; Hammar, Ingela

doi:10.1016/0306-4522(95)00060-v

Cited by 15 publications

(9 citation statements)

References 29 publications

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“…Observations made on 12 of these neurons have been reported previously (Jankowska et al, 1995b). In contrast to the negligible effects of noradrenaline, serotonin had marked effects on responses of these neurons.…”

Section: Modulatory Actions Of Serotoninmentioning

confidence: 61%

“…Belcher et al, 1978;Headley et al, 1978), with the exception of flexor reflex pathways (AndCn et al, 1966). Modulation of transmission from group I1 muscle afferents and low-threshold cutaneous afferents has nevertheless been found in synapscs with some spinal interneurons (Bras et al, 1989b(Bras et al, , 1990Schomburg and Steffens, 1988), dorsal horn dorsal spinocerebellar tract neurons (Jankowska et al, 1995b) and some unidentified dorsal horn neurons (Howe and Zieglgansberger, 1987). The aim of the present study was therefore to extend the analysis of modulatory actions of serotonin and noradrenaline on transmission from group I1 muscle afferents and low-threshold skin afferents to four types of ascending tract neurons: neurons in the spinocervical tract (SCT), neurons in the postsynaptic dorsal column (PSDC; Brown,198 l), dorsal spinocerebellar tract (DSCT) neurons in Clarke's column, and a population of DSCT neurons located in the dorsal horn (Brown, 198 I ;Edgley and Jankowska, 1988).…”

Section: Introductionmentioning

confidence: 99%

“…Belcher et al, 1978;Headley et at., 1978;El-Yassir et aL., 1988). Dorsal horn DSCT cells were tested only for effects of serotonin (Jankowska et al, 1995b) and no studies have apparently been made on the effects of either noradrenaline or serotonin on Clarke's column DSCT cells. Morphological studies have revealed contacts made by serotoninergic fibres with PSDC neurons (Nishikawa et al., 1983), IISCT neurons in the dorsal horn (Jankowska et al, 1995;Maxwell and Jankowska, 1996) and DSCT neurons in Clarke's column (Pearson et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

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Modulation of Responses of Four Types of Feline Ascending Tract Neurons by Serotonin and Noradrenaline

Jankowska

Hammar

Djouhri

et al. 1997

Eur J of Neuroscience

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Modulation of responses of four types of ascending tract cells by noradrenaline and serotonin was compared in order to investigate how information forwarded by these cells may be gated by monoaminergic tract neurons. Spinocervical tract, postsynaptic dorsal column and dorsal spinocerebellar tract neurons located in Clarke's column and in the dorsal horn were identified by their axonal projections. Noradrenaline and serotonin were applied ionophoretically close to a selected neuron, and their effects were tested on extracellularly recorded responses of this neuron to electrical stimulation of low-threshold skin afferents and group II muscle spindle afferents. The modulatory actions of noradrenaline and serotonin were estimated from changes in the number of responses evoked by 30 successive stimuli, the minimal latencies of these responses, and their firing frequency. All four populations of ascending tract neurons investigated were modulated by serotonin and noradrenaline, but not in the same way. The responses were most often depressed by noradrenaline and facilitated by serotonin, but in some types of neuron they were affected in the same direction. Transmission from low-threshold skin and group II muscle afferents changed in the same direction in some types of neuron but in the opposite direction in other types. 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.

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Section: Modulatory Actions Of Serotoninmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modulation of Responses of Four Types of Feline Ascending Tract Neurons by Serotonin and Noradrenaline

Jankowska

Hammar

Djouhri

et al. 1997

Eur J of Neuroscience

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“…Thus, decreases in latency occur in conjunction with increases in spike count or firing rate, and increases in latency occur in conjunction with decreases in spike count or firing rate (Bras et al, 1989;Jankowska et al, 1995Jankowska et al, , 1998Saruhashi et al, 1997;Hammar et al, 2002;Shay and Hochman, 2002). Such coordinated changes in multiple response properties could indicate a mechanism that changes general neural responsiveness.…”

Section: The Effects Of Serotonin On Latency Versus Spike Count and Imentioning

confidence: 99%

“…The latencies of sensory neurons vary in response to neuromodulators such as norepinephrine or serotonin (Bras et al, 1989;Jankowska et al, 1995Jankowska et al, , 1998Saruhashi et al, 1997;Hammar et al, 2002;Shay and Hochman, 2002;Devilbiss and Waterhouse, 2004). This is unsurprising, because many of the factors that establish latencies, such as membrane conductances and the convergence of excitatory and inhibitory inputs, also show neuromodulator-gated plasticity.…”

Section: Introductionmentioning

confidence: 99%

Serotonin Shifts First-Spike Latencies of Inferior Colliculus Neurons

Hurley¹,

Pollak²

2005

J. Neurosci.

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Many studies of neuromodulators have focused on changes in the magnitudes of neural responses, but fewer studies have examined neuromodulator effects on response latency. Across sensory systems, response latency is important for encoding not only the temporal structure but also the identity of stimuli. In the auditory system, latency is a fundamental response property that varies with many features of sound, including intensity, frequency, and duration. To determine the extent of neuromodulatory regulation of latency within the inferior colliculus (IC), a midbrain auditory nexus, the effects of iontophoretically applied serotonin on first-spike latencies were characterized in the IC of the Mexican free-tailed bat. Serotonin significantly altered the first-spike latencies in response to tones in 24% of IC neurons, usually increasing, but sometimes decreasing, latency. Serotonin-evoked changes in latency and spike count were not always correlated but sometimes occurred independently within individual neurons. Furthermore, in some neurons, the size of serotonin-evoked latency shifts depended on the frequency or intensity of the stimulus, as reported previously for serotonin-evoked changes in spike count. These results support the general conclusion that changes in latency are an important part of the neuromodulatory repertoire of serotonin within the auditory system and show that serotonin can change latency either in conjunction with broad changes in other aspects of neuronal excitability or in highly specific ways.

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A confocal and electron microscopic study of contacts between 5-HT fibres and feline dorsal horn interneurons in pathways from muscle afferents

et al. 1997

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Morphological substrates of actions of serotonin upon dorsal horn interneurons with input from group II muscle afferents were investigated by using two experimental approaches. Twelve interneurons were intracellularly labelled with rhodamine-dextran, and serotoninergic fibres were identified by immunofluorescence. Appositions between the serotoninergic axons and these interneurons were examined with a dual-channel confocal microscope. A further four interneurons were intracellularly labelled with horseradish peroxidase, and serotoninergic axons were identified by immunocytochemistry; these neurons were prepared for combined light and electron microscopy. Confocal microscopy revealed serotoninergic varicosities in apposition to both cell bodies and dendrites. Similar total numbers of appositions were found on the soma, and on dendrites within 100 microm from the soma, on the most completely labelled neurons. The number of appositions on 100-microm segments of dendrites decreased with increasing distances from the soma (from 14.6 within 100 microm, to 3.8 and 2.4 at 100-300 microm, and more than 300 microm distances, respectively). Electron microscopic analysis of two neurons revealed that few of the apparent contacts on cell bodies were synaptic, but, in contrast, many varicosities apposed to proximal dendrites formed synapses. The evidence suggests that serotonin may have more powerful synaptic effects upon the dendrites of this class of dorsal horn interneurons than on their cell bodies.

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Effects of serotonin on dorsal horn dorsal spinocerebellar tract neurons

Cited by 15 publications

References 29 publications

Modulation of Responses of Four Types of Feline Ascending Tract Neurons by Serotonin and Noradrenaline

Modulation of Responses of Four Types of Feline Ascending Tract Neurons by Serotonin and Noradrenaline

Serotonin Shifts First-Spike Latencies of Inferior Colliculus Neurons

A confocal and electron microscopic study of contacts between 5-HT fibres and feline dorsal horn interneurons in pathways from muscle afferents

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