Differential innervation of specific motor neuron pools by serotoninergic fibers in the chick spinal cord

Okado, Nobuo; Homma, Shunsaku; Ishihara, Rieko; Sako, Hiroko; Kohno, Kunio

doi:10.1016/0304-3940(88)90265-0

Cited by 19 publications

(7 citation statements)

References 13 publications

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“…8A). This functional action of 5HT2A/C receptors on gait patterns fits with their preferential influence on the properties of extensor motoneurons and on the layer of interneurons that shape motor output in lower lumbosacral segments (Okado et al, 1988; Liu and Jordan, 2005). However, Jordan et al (2008) suggested that 5HT2A-possesing cells exert limited direct influences on rhythm-generating components of the spinal locomotor system.…”

Section: Discussionsupporting

confidence: 58%

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

Musienko

Brand²,

Märzendorfer³

et al. 2011

Journal of Neuroscience

135

102

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Descending monoaminergic inputs markedly influence spinal locomotor circuits, but the functional relationships between specific receptors and the control of walking behavior remain poorly understood. To identify these interactions, we manipulated serotonergic, dopaminergic, and noradrenergic neural pathways pharmacologically during locomotion enabled by electrical spinal cord stimulation in adult spinal rats in vivo. Using advanced neurobiomechanical recordings and multidimensional statistical procedures, we reveal that each monoaminergic receptor modulates a broad but distinct spectrum of kinematic, kinetic and EMG characteristics, which we expressed into receptor–specific functional maps. We then exploited this catalogue of monoaminergic tuning functions to devise optimal pharmacological combinations to encourage locomotion in paralyzed rats. We found that, in most cases, receptor-specific modulatory influences summed near algebraically when stimulating multiple pathways concurrently. Capitalizing on these predictive interactions, we elaborated a multidimensional monoaminergic intervention that restored coordinated hindlimb locomotion with normal levels of weight bearing and partial equilibrium maintenance in spinal rats. These findings provide new perspectives on the functions of and interactions between spinal monoaminergic receptor systems in producing stepping, and define a framework to tailor pharmacotherapies for improving neurological functions after CNS disorders.

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Section: Discussionsupporting

confidence: 58%

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

Musienko

Brand²,

Märzendorfer³

et al. 2011

Journal of Neuroscience

135

102

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“…This local variation within the motor nucleus was in fact noted already by Fuxe (1965). (See also studies in various mammals by Kojima and Sano, 1983 and in chicken by Okado et al, 1988.) The variation does not necessarily reflect a varying density in the innervation of motoneurons of different pools, since the dendritic tree of individual alpha motoneurons spans over a large area of the ventral horn (Cullheim and Kellerth, 1976;Ulfhake and Kellerth, 1981).…”

Section: A-d)mentioning

confidence: 99%

5‐Hydroxytryptamine, substance P, and thyrotropin‐releasing hormone in the adult cat spinal cord segment L₇: Immunohistochemical and chemical studies

Arvidsson

Cullheim

Ulfhake

et al. 1990

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The terminal projections of the descending 5-hydroxytryptamine (5-HT) bulbospinal pathway and the coexistence among 5-HT-, substance P (SP)-, and thyrotropin-releasing hormone (TRH)-like immunoreactivities (LI) in fibers innervating the L7 segment in the cat spinal cord were studied quantitatively and semiquantitatively by use of the indirect double-staining immunofluorescence technique. The content of 5-HT, SP, and TRH in different parts of the spinal cord was determined by use of radioimmunoassay (RIA) (SP and TRH) and high-performance liquid chromatography with electrochemical detection (HPLC-ECD) (5-HT). For all three substances studied, immunoreactive (IR) axon terminals were found in all parts of the gray matter, but with clear regional variation in the density of innervation. Thus, all three substances showed a dense innervation in the motor nucleus, particularly in the ventral part of the nucleus, while the superficial dorsal horn was very densely innervated by SP-IR fibers (laminae I and II) and TRH-IR fibers (laminae II and III). In the motor nucleus, the studied substances coexisted to a very high degree, but some 5-HT-IR fibers (about 10%) lacked peptide-LI and some SP-IR fibers (about 10%) lacked 5-HT-LI while virtually all TRH-IR fibers also contained 5-HT-LI. In the superficial dorsal horn (laminae I-III), no coexistence was detected, while other parts of the gray matter displayed various degrees of coexistence in between those found in the motor nucleus and laminae I-III. The quantitative analysis of IR varicosities in the motor nucleus suggested that the unilateral L7 motor nucleus is innervated by about 55-110 x 10(6) 5-HT-IR nerve terminals, which may indicate as many as 4,000 boutons per descending 5-HT cell body in the brain stem only with this restricted projection. When combing these results with the biochemical data, it could be calculated that the concentration of 5-HT in IR varicosities is about 3-6 x 10(-3) M, while the corresponding figures for SP and TRH was 0.3-0.5 x 10(-3) M and 0.1-0.2 x 10(-3) M, respectively. In cats subjected to spinal cord transection at the lower thoracic level, all 5-HT-IR fibers in the L7 segment had disappeared 44 days after the lesion, indicating a strict suprasegmental origin of 5-HT-IR fibers in this segment.(ABSTRACT TRUNCATED AT 400 WORDS)

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“…1988) demonstrated that serotoninergic inputs to motoneurons in the cat extend the duration of the motoneuron excitability elicited by a train of Ia afferent impulses. It seems likely that MNPs of the posterior iliotibial, femorotibial, iliofibular and caudilioflexorius muscles, which may have monosynaptic connections with primary afferents as well as with serotoninergic fibers Okado et al 1988), mediate tonic excitatory responses involved in maintaining an upright posture in chickens.…”

Section: Axonal Inputs To Mnpsmentioning

confidence: 99%

“…Our previous studies Okado et al 1988) demonstrated that MNPs innervating the extensor muscles of hip joint (for standing) in the chicken received a dense innervation by serotoninergic fibers. Differential innervation of MNPs by serotoninergic fibers appeared to be related to whether or not the motor neurons and muscles were involved in maintaining an upright standing posture.…”

Section: Introductionmentioning

confidence: 99%

Distribution patterns of dendrites in motor neuron pools of lumbosacral spinal cord of the chicken

et al. 1990

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The morphology of dendritic trees (dendroarchitecture) of motor neurons innervating specific hindlimb muscles (motoneuron pools, MNP) was studied in the chick spinal cord. Motoneurons were labelled by intramuscular injections of horseradish peroxidase conjugated with cholera toxin subunit B. MNPs of posterior iliotibial and femorotibial muscles were located at the dorsolateral part of lateral motor column of lumbosacral segments (LS) 1-4 and 1-3, respectively. Although the dendritic profiles of femorotibialis motoneurons were fewer than those of posterior iliotibialis, these two MNPs had a similar distribution pattern of dendrites. Dendritic profiles were about equally distributed in the gray and white matter. Dendrites from the MNP of posterior iliotibialis radiated in all directions. A large number of dendrites penetrated into the white matter, and some even reached to the subpial regions of the lateral funiculus. One array of dendrites that projected dorsomedialwards extended to the base of the posterior horn. MNPs of both the iliofibularis (LS 4-7) and caudilioflexorius (LS 6-8) had dendritic trees with similar distribution patterns. There were two main arrays of dendritic extensions; one along the dorsal, and another along the ventral border of the lateral motor column. Dendrites from the iliofibularis and caudilioflexorius motoneurons were located more frequently in the white matter than in the gray matter. A large number of dendrites extended in all directions from the MNP of the adductor muscle, which was located in the medial region of lateral motor column of LS 1-2. The distribution of dendrites from a few other MNPs was also examined.(ABSTRACT TRUNCATED AT 250 WORDS)

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Differential innervation of specific motor neuron pools by serotoninergic fibers in the chick spinal cord

Cited by 19 publications

References 13 publications

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

5‐Hydroxytryptamine, substance P, and thyrotropin‐releasing hormone in the adult cat spinal cord segment L₇: Immunohistochemical and chemical studies

Distribution patterns of dendrites in motor neuron pools of lumbosacral spinal cord of the chicken

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Differential innervation of specific motor neuron pools by serotoninergic fibers in the chick spinal cord

Cited by 19 publications

References 13 publications

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

Controlling Specific Locomotor Behaviors through Multidimensional Monoaminergic Modulation of Spinal Circuitries

5‐Hydroxytryptamine, substance P, and thyrotropin‐releasing hormone in the adult cat spinal cord segment L7: Immunohistochemical and chemical studies

Distribution patterns of dendrites in motor neuron pools of lumbosacral spinal cord of the chicken

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5‐Hydroxytryptamine, substance P, and thyrotropin‐releasing hormone in the adult cat spinal cord segment L₇: Immunohistochemical and chemical studies