Study of 5-HT release with a chronically implanted microdialysis probe in the ventral horn of the spinal cord of unrestrained rats during exercise on a treadmill

Gerin, Christine; Legrand, André; Privat, Alain

doi:10.1016/0165-0270(94)90121-x

Cited by 43 publications

(37 citation statements)

References 64 publications

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“…5-HT and NA fibers exist at all spinal segments in the perinatal rodent (Ballion et al 2002;Rajaofetra et al 1992). At least a portion of these fibers are likely functional because stimulation of the parapyramidal area in the brain stem elicits 5-HT-dependent locomotor-like activity (Liu and Jordan 2005) and separate studies confirm the release of 5-HT and NA metabolites in the ventral horn of adult and neonatal rats during brain stem stimulation or exercise (Gerin et al 1994(Gerin et al , 1995Jordan and Schmidt 2002). Less data are available for the dopaminergic system; however, DA fibers and receptors are present in the rat spinal cord (Holstege et al 1996;Ridet et al 1992;Yoshida and Tanaka 1988) and are functional (Fleetwood-Walker et al 1988).…”

Section: Functional Considerationsmentioning

confidence: 49%

Monoaminergic Control of Cauda-Equina-Evoked Locomotion in the Neonatal Mouse Spinal Cord

Gordon

Whelan²

2006

Journal of Neurophysiology

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. Monoaminergic projections are among the first supraspinal inputs to innervate spinal networks. Little is known regarding the role of monoamines in modulating ongoing locomotor patterns evoked by endogenous release of neurotransmitter. Here we activate a locomotor-like rhythm by electrical stimulation of afferents and then test the modulatory effects of monoamines on the frequency, pattern, and quality of the rhythm. Stimulation of the cauda equina induced a rhythm consisting of left-right and ipsilateral alternation indicative of locomotor-like activity. First, we examined the effects of noradrenaline (NA), serotonin (5-HT), or dopamine (DA) at dose levels that did not elicit locomotor activity. Bath application of NA and DA resulted in a depression of the cauda-equina-evoked rhythm. Conversely, bathapplied 5-HT increased both the amplitude and cycle period of the evoked rhythm, an effect that was mimicked by the addition of 5-HT 2 agonists to the bath. Application of 5-HT 7 agonists disrupted the evoked rhythmic behavior. Next, we examined the effects of NA ␣ 1 and ␣ 2 agonists and found that the suppressive effects of NA on the rhythm could be reproduced by adding the ␣ 2 agonist, clonidine, to the bath. In contrast, bath applying the ␣ 1 agonist, phenylephrine, increased the amplitude and duration of the cycle period. Finally, the suppressive effects of DA were not replicated by the administration of D 1 , D 2 , or D 3 agonists although application of NA ␣ 2 antagonists reversed the effects of DA. Application of D 1 agonists, increased the amplitude of the bursts but did not affect the cycle period. Our results indicate that monoamines can control the expression, pattern, and timing of cauda-equina-evoked locomotor patterns in developing mice.

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Section: Functional Considerationsmentioning

confidence: 49%

Monoaminergic Control of Cauda-Equina-Evoked Locomotion in the Neonatal Mouse Spinal Cord

Gordon

Whelan²

2006

Journal of Neurophysiology

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“…Consistent with this, Dishman and colleagues have reported that voluntary exercise in rats was associated with decreased shock-induced elevation in the 5-HT metabolite 5-hydroxyindole acetic acid in the hippocampus and amygdala suggesting that exercise decreased 5-HT function in these DRN targets associated with anxiety-like behavior. It is interesting to note that treadmill (i.e., forced) exercise has been shown to increase 5-HT release in the hippocampus, frontal cortex, and spinal cord Gerin, Legrand, & Privat, 1994;Gomez-Merino, Bequet, Berthelot, Chennaoui, & Guezennec, 2001;Meeusen et al, 1996). Treadmill running appears to be qualitatively different from voluntary exercise and has been argued to be more akin to stress .…”

Section: Discussionmentioning

confidence: 99%

Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle.

Fox

Hammack²,

Falls³

2008

Behavioral Neuroscience

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Voluntary exercise has been associated with reduced anxiety across several animal models. Manipulation of central 5-HT can alter anxiety-like behaviors and administration of the 5-HT agonist metachlorophenylpiperazine (mCPP) increases anxiety in rodents and humans. To examine whether the anxiolytic effect of exercise is associated with an alteration in 5-HT systems, we examined the anxiogenic effect of mCPP in exercising and nonexercising mice. C57BL/6J mice were given 2 weeks of free access to either a functioning or nonfunctioning running wheel. Mice were then tested for acoustic startle following systemic injection of either 0, 0.1, 0.3, or 1 mg/kg of mCPP. Consistent with its anxiogenic properties, mCPP produced a dose-dependent increase in acoustic startle in nonexercising mice. However, this anxiogenic effect was blunted in exercising mice. These findings suggest that exercise may help to reduce anxiety by altering 5-HT systems, perhaps by down-regulating postsynaptic 5HT 2B/2C receptors.

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“…Animals were placed in a spinal stereotactic aparatus (David Kopf Instruments, USA). A microdialysis probe (membrane diameter of 240μm, cut off of 6000 Daltons, CMA11/1 mm, CMA/Microdialysis, Sweden) was stereotactically inserted into the L4 dorsal horn segment of the spinal cord (vertebral body T13) [6] in layers II, III, IV, V of Rexed [10,11]. As proprioceptive areas are located within laminae III, IV, V the specific placement of the membrane of the probe allowed for sampling from proprioceptive areas within the dorsal horn.…”

Section: Stereotactic Microdialysis Probe Placement Into the Dorsal Hmentioning

confidence: 99%

“…Stereotactic coordinates were set with reference to T13 spinous process apex: AP= -4.0 mm; L= 0.64±0.14 mm; H= +0.72 ±0.06 mm (from dura), with an angle of 16°to the horizontal fixation of the probes to the vertebra. Muscles and skin were sutured plan by plan [6].…”

Section: Stereotactic Microdialysis Probe Placement Into the Dorsal Hmentioning

confidence: 99%

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Motor activity induces release of serotonin in the dorsal horn of the rat lumbar spinal cord

Gerin

Teilhac

Smith

et al. 2008

Neuroscience Letters

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Literature highlights that serotonergic descending pathways [14] are implicated in somatosensory functions in the spinal cord and that serotonin (5-HT) in the dorsal horn might play a role in motor function through proprioceptive feedback [3,8,9,13]. We hypothesized that 5-HT release in dorsal horn might represent an important factor in the completion of locomotion by facilitation of the spinocerebellar tract [8] and/or by modulation of spinal reflex pathways [9]. The present study demonstrates that during locomotor activity, 5-HT is released in layers II, III, IV, V of Rexed laminae. Microdialysis in combination with HPLC was used to measure concentrations of neurotransmitters in the lumbar dorsal horn before, during, and after a treadmill running exercise. Our results show a significant 41% increase of 5-HT release within the dorsal horn during a running exercise. 5-HT release is temporally related to exercise. The present study demonstrates that dorsal horn 5-HT release might modulate locomotion.

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Study of 5-HT release with a chronically implanted microdialysis probe in the ventral horn of the spinal cord of unrestrained rats during exercise on a treadmill

Cited by 43 publications

References 64 publications

Monoaminergic Control of Cauda-Equina-Evoked Locomotion in the Neonatal Mouse Spinal Cord

Monoaminergic Control of Cauda-Equina-Evoked Locomotion in the Neonatal Mouse Spinal Cord

Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle.

Motor activity induces release of serotonin in the dorsal horn of the rat lumbar spinal cord

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