Rhythmic Motor Activity in Thin Transverse Slice Preparations of the Fetal Rat Spinal Cord

2004 ◽  
Vol 92 (1) ◽  
pp. 648-652 ◽  
Author(s):  
Kiyomi Nakayama ◽  
Hiroshi Nishimaru ◽  
Norio Kudo
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Temporal Correlation ◽  
Rhythmic Activity ◽  
Lumbar Spinal Cord ◽  
Rat Spinal Cord ◽  
Commissural Neurons ◽  
Rhythmic Motor ◽  
Lumbar Spinal ◽  
Transverse Slice

Networks generating locomotor-like rhythmic motor activity are formed during the last week of the fetal period in the rat spinal cord. We investigated the coordinated rhythmic motor activity induced in transverse slice preparations of the lumbar spinal cord taken from fetal rats as early as embryonic day (E) 16.5. In slices as thin as 100 μm, bath-application of 5-hydroxytryptamine (5-HT) induced rhythmic [Ca2+]i elevations in motoneurons labeled with Calcium Green-1 dextran. The rhythmic [Ca2+]i elevations were similar in frequency to that in the intact lumbar spinal cord, although there was no temporal correlation between the activity in the left and right sides of 100-μm slices. Such rhythmic [Ca2+]i elevations were observed in the slices taken from all lumbar segments. Moreover, the rhythmic activity was abolished by simultaneous blockade of glutamate, glycine, and GABAA receptors, indicating that synaptic transmission mediated by these receptors is important for the generation of the rhythm in these slices. Synchronous rhythmic activity between the left-right sides was found in slices thicker than 200 μm taken from any segmental level of the lumbar spinal cord. In these preparations, commissural neurons were activated synchronously with ipsilateral motoneurons. These results indicate that the neuronal networks sufficient to generate coordinated rhythmic activity are contained in one-half of a single lumbar segment at E16.5. Such spinal cord slices are a promising experimental model to investigate the neuronal mechanisms and the development of rhythm generation in the spinal cord.

Effects of inhibitory amino acid antagonists on reciprocal inhibitory interactions during rhythmic motor activity in the in vitro neonatal rat spinal cord

1995 ◽  
Vol 74 (3) ◽  
pp. 1109-1117 ◽  
Author(s):  
K. C. Cowley ◽  
B. J. Schmidt
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Receptor Agonist ◽  
Gabab Receptor ◽  
Glycine Receptor ◽  
Rhythmic Activity ◽  
Neonatal Rat ◽  
Rat Spinal Cord ◽  
Rhythmic Motor

1. The role of inhibitory amino acid transmission in the coordination and generation of rhythmic motor activity was examined with the use of an in vitro neonatal rat spinal cord preparation. Before adding gamma-aminobutyric acid (GABA) or glycine receptor agonists and antagonists, rhythmic motor activity was induced by bath application of acetylcholine (ACh), N-methyl-D,L-aspartate (NMA), or serotonin (5-HT) while monitoring bilateral ankle flexor and extensor electroneurograms (ENGs). The timing of rhythmic flexor and extensor discharge was consistent with that seen during overground locomotion in 27% of 84 bath applications of these substances (n = 65 preparations). 2. Subsequent addition of the GABAA receptor agonist muscimol, the GABAB receptor agonist baclofen, or glycine, abolished rhythmic activity in 95% of the tested applications. 3. GABAB receptor blockade did not disrupt alternating patterns of ENG discharge. However, addition of the GABAA receptor antagonist bicuculline, or the glycine receptor antagonist strychnine, transformed alternating flexor-extensor and left-right activity into patterns characterized by bilaterally synchronous rhythmic activation of all hindlimb ENGs. The onset of individual ENG bursts was more abrupt following bicuculline or strychnine. Strychnine also synchronized high-frequency (4-8 Hz) packets of rhythmic discharge within ENG bursts. 4. Some preparations developed synchronous, but unstable, rhythmic activity in the presence of bicuculline or strychnine alone. However, NMA, 5-HT, or ACh was usually required in addition to these antagonists to promote sustained rhythmic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Motor activity affects dopaminergic and noradrenergic systems of the dorsal horn of the rat lumbar spinal cord

Synapse ◽  
2011 ◽  
Vol 65 (12) ◽  
pp. 1282-1288 ◽  
Author(s):  
Christine G. Gerin ◽  
Kristin Smith ◽  
Seritta Hill ◽  
Angela Hill ◽  
Ikenna C. Madueke
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Dorsal Horn ◽  
Lumbar Spinal Cord ◽  
Lumbar Spinal

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

2008 ◽  
Vol 436 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Christine Gerin ◽  
Jean-Rene Teilhac ◽  
Kristin Smith ◽  
Alain Privat
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Dorsal Horn ◽  
Lumbar Spinal Cord ◽  
Lumbar Spinal

Interactions Between Multiple Rhythm Generators Produce Complex Patterns of Oscillation in the Developing Rat Spinal Cord

2002 ◽  
Vol 87 (2) ◽  
pp. 1094-1105 ◽  
Author(s):  
Rezan Demir ◽  
Bao-Xi Gao ◽  
Meyer B. Jackson ◽  
Lea Ziskind-Conhaim
Keyword(s):  
Spinal Cord ◽  
Spatial Organization ◽  
Imaging Techniques ◽  
Field Potential ◽  
Phase Relationship ◽  
Rhythmic Activity ◽  
Lumbar Spinal Cord ◽  
Spatiotemporal Pattern ◽  
Neonatal Rats ◽  
Lumbar Spinal

Neural networks capable of generating coordinated rhythmic activity form at early stages of development in the spinal cord. In this study, voltage-imaging techniques were used to examine the spatiotemporal pattern of rhythmic activity in transverse slices of lumbar spinal cord from embryonic and neonatal rats. Real-time images were recorded in slices stained with the voltage-sensitive fluorescent dye RH414 using a 464-element photodiode array. Fluorescence signals showed spontaneous voltage oscillations with a frequency of 3 Hz. Simultaneous recordings of fluorescence and extracellular field potential demonstrated that the two signals oscillated with the same frequency and had a distinct phase relationship, indicating that the fluorescence changes represented changes in transmembrane potentials. The oscillations were reversibly blocked by cobalt (1 mM), indicating a dependence on Ca2+ influx through voltage-gated Ca2+ channels. Extracellular field potentials revealed oscillations with the same frequency in both stained and unstained slices. Oscillations were apparent throughout a slice, although their amplitudes varied in different regions. The largest amplitude oscillations were produced in the lateral regions. To examine the spatial organization of rhythm-generating networks, slices were cut into halves and quarters. Each fragment continued to oscillate with the same frequency as intact slices but with smaller amplitudes. This finding suggested that rhythm-generating networks were widely distributed and did not depend on long-range projections. In slices from neonatal rats, the oscillations exhibited a complex spatiotemporal pattern, with depolarizations alternating between mirror locations in the right and left sides of the cord. Furthermore, within each side depolarizations alternated between the lateral and medial regions. This medial-lateral pattern was preserved in hemisected slices, indicating that pathways intrinsic to each side coordinated this activity. A different pattern of oscillation was observed in slices from embryos with synchronous 3-Hz oscillations occurring in limited regions. Our study demonstrated that rhythm generators were distributed throughout transverse sections of the lumbar spinal cord and exhibited a complex spatiotemporal pattern of coordinated rhythmic activity.

scholarly journals Reactive changes in the rat spinal cord in experimental neuropathy with and without magnetic stimulation

2019 ◽  
Vol 21 (2) ◽  
pp. 166-172
Author(s):  
S A Zhivolupov ◽  
N A Rashidov ◽  
L S Onishchenko ◽  
A Yu Kravchuk ◽  
O V Kostina ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Transcranial Magnetic Stimulation ◽  
Glial Cells ◽  
Magnetic Stimulation ◽  
Morphological Data ◽  
Lumbar Spinal Cord ◽  
Rat Spinal Cord ◽  
Recovery Processes ◽  
Reactive Changes ◽  
Lumbar Spinal

Performing an experiment in which electronically microscopically studied the nature of reactive changes in the structural thin section of the spinal cord, as well as their dynamics during transcranial magnetic stimulation for 1 month after experimental neuromesis and after compression-ischemic neuropathy of the sciatic nerve. The reported development of compensatory-restorative processes in neurons, glial cells and the microvasculature of the lumbar spinal cord in rats that receive treatment with transcranial magnetic stimulation has been established. It was shown, that in all groups of rats changes in the structures of the lumbar thickening of the rat spinal cord developed in the form of depletion of the cytoplasm, destruction of organelles, changes in the nuclei and development of apoptosis of neurons and glial cells, destruction of the membranes and axial cylinders of myelin fibers. Moreover, these changes are more pronounced in groups after experimental neuromesis. However, in groups of rats, both after compression-ischemic neuropathy and after experimental neuromesis after treatment with transcranial magnetic stimulation, there were signs of the development of recovery processes in the form of intracellular repair of neurons, proliferation of oligodendrocytes, restoration of the structure of myelin fibers and capillaries, and the absence of free red blood cells in the extracellular space. The obtained morphological data confirm the effectiveness of treatment of transcranial magnetic stimulation of injuries of the peripheral nervous system in relation to neurons, glial cells, myelin and non-myelin fibers of the spinal cord.

Ontogeny of Rhythmic Motor Patterns Generated in the Embryonic Rat Spinal Cord

2003 ◽  
Vol 89 (3) ◽  
pp. 1187-1195 ◽  
Author(s):  
Jun Ren ◽  
John J. Greer
Keyword(s):  
Spinal Cord ◽  
Spontaneous Activity ◽  
Developmental Stages ◽  
Rhythmic Activity ◽  
Late Gestation ◽  
Spatiotemporal Pattern ◽  
Rat Spinal Cord ◽  
Motor Patterns ◽  
Rhythmic Motor

Patterned spontaneous activity is generated in developing neuronal circuits throughout the CNS including the spinal cord. This activity is thought to be important for activity-dependent neuronal growth, synapse formation, and the establishment of neuronal networks. In this study, we examine the spatiotemporal distribution of motor patterns generated by rat spinal cord and medullary circuits from the time of initial axon outgrowth through to the inception of organized respiratory and locomotor rhythmogenesis during late gestation. This includes an analysis of the neuropharmacological control of spontaneous rhythms generated within the spinal cord at different developmental stages. In vitro spinal cord and medullary-spinal cord preparations isolated from rats at embryonic ages (E)13.5–E21.5 were studied. We found age-dependent changes in the spatiotemporal pattern, neurotransmitter control, and propensity for the generation of spontaneous rhythmic motor discharge during the prenatal period. The developmental profile of the neuropharmacological control of rhythmic bursting can be divided into three periods. At E13.5–E15.5, the spinal networks comprising cholinergic and glycinergic synaptic interconnections are capable of generating rhythmic activity, while GABAergic synapses play a role in supporting the spontaneous activity. At late stages (E18.5–E21.5), glutamate drive acting via non- N-methyl-d-aspartate (non-NMDA) receptors is primarily responsible for the rhythmic activity. During the middle stage (E16.5–E17.5), the spontaneous activity results from the combination of synaptic drive acting via non-NMDA glutamatergic, nicotinic acetylcholine, glycine, and GABAA receptors. The modulatory actions of chloride-mediated conductances shifts from predominantly excitatory to inhibitory late in gestation.

scholarly journals Spinal V3 interneurons and left-right coordination in mammalian locomotion

2019 ◽  
Author(s):  
Simon M. Danner ◽  
Han Zhang ◽  
Natalia A. Shevtsova ◽  
Joanna Borowska ◽  
Ilya A. Rybak ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Rhythmic Activity ◽  
Contralateral Side ◽  
Lumbar Spinal Cord ◽  
Spinal Neurons ◽  
Ipsilateral Side ◽  
Current Experimental Data ◽  
Left And Right ◽  
Lumbar Spinal

AbstractCommissural interneurons (CINs) mediate interactions between rhythm-generating locomotor circuits located on each side of the spinal cord and are necessary for left-right limb coordination during locomotion. While glutamatergic V3 CINs have been implicated in left-right coordination, their functional connectivity remains elusive. Here, we addressed this issue by combining experimental and modeling approaches. We employed Sim1Cre/+; Ai32 mice, in which light-activated Channelrhodopsin-2 was selectively expressed in V3 interneurons. Fictive locomotor activity was evoked by NMDA and 5-HT in the isolated neonatal lumbar spinal cord. Flexor and extensor activities were recorded from left and right L2 and L5 ventral roots, respectively. Bilateral photoactivation of V3 interneurons increased the duration of extensor bursts resulting in a slowed down on-going rhythm. At high light intensities, extensor activity could become sustained. When light stimulation was shifted toward one side of the cord, the duration of extensor bursts still increased on both sides, but these changes were more pronounced on the contralateral side than on the ipsilateral side. Additional bursts appeared on the ipsilateral side not seen on the contralateral side. Further increase of the stimulation could suppress the contralateral oscillations by switching to a sustained extensor activity, while the ipsilateral rhythmic activity remained. To delineate the function of V3 interneurons and their connectivity, we developed a computational model of the spinal circuits consisting of two (left and right) rhythm generators (RGs) interacting via V0V, V0D and V3 CINs. Both types of V0 CINs provided mutual inhibition between the left and right flexor RG centers and promoted left-right alternation. V3 CINs mediated mutual excitation between the left and right extensor RG centers. These interactions allowed the model to reproduce our current experimental data, while being consistent with previous data concerning the role of V0V and V0D CINs in securing left-right alternation and the changes in left-right coordination following their selective removal. We suggest that V3 CINs provide mutual excitation between the spinal neurons involved in the control of left and right extensor activity, which may promote left-right synchronization during locomotion.

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