Reformation of specific synaptic connections by regenerating sensory axons in the spinal cord of the bullfrog

1986 ◽  
Vol 5 (3) ◽  
pp. 165-185 ◽  
Author(s):  
Eric Frank ◽  
Dinah W. Sah
Keyword(s):  
Spinal Cord ◽  
Synaptic Connections ◽  
Sensory Axons

scholarly journals Intravital Assessment of Cells Responses to Conducting Polymer-Coated Carbon Microfibres for Bridging Spinal Cord Injury

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 73
Author(s):  
Bilal El Waly ◽  
Vincent Escarrat ◽  
Jimena Perez-Sanchez ◽  
Jaspreet Kaur ◽  
Florence Pelletier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Immune Cell ◽  
Two Photon ◽  
Sensory Axons ◽  
Promising Therapeutic Approach ◽  
Cord Injury ◽  
Biochemical Signals ◽  
Coated Carbon ◽  
Striking Effect

The extension of the lesion following spinal cord injury (SCI) poses a major challenge for regenerating axons, which must grow across several centimetres of damaged tissue in the absence of ordered guidance cues. Biofunctionalized electroconducting microfibres (MFs) that provide biochemical signals, as well as electrical and mechanical cues, offer a promising therapeutic approach to help axons overcome this blind journey. We used poly(3,4-ethylenedioxythiophene)-coated carbon MFs functionalized with cell adhesion molecules and growth factors to bridge the spinal cord after a partial unilateral dorsal quadrant lesion (PUDQL) in mice and followed cellular responses by intravital two-photon (2P) imaging through a spinal glass window. Thy1-CFP//LysM-EGFP//CD11c-EYFP triple transgenic reporter animals allowed real time simultaneous monitoring of axons, myeloid cells and microglial cells in the vicinity of the implanted MFs. MF biocompatibility was confirmed by the absence of inflammatory storm after implantation. We found that the sprouting of sensory axons was significantly accelerated by the implantation of functionalized MFs after PUDQL. Their implantation produced better axon alignment compared to random and misrouted axon regeneration that occurred in the absence of MF, with a most striking effect occurring two months after injury. Importantly, we observed differences in the intensity and composition of the innate immune response in comparison to PUDQL-only animals. A significant decrease of immune cell density was found in MF-implanted mice one month after lesion along with a higher ratio of monocyte-derived dendritic cells whose differentiation was accelerated. Therefore, functionalized carbon MFs promote the beneficial immune responses required for neural tissue repair, providing an encouraging strategy for SCI management.

An EM analysis of the synaptic connections of horseradish peroxidase-filled stalked cells and islet cells in the substantia gelatinosa of adult cat spinal cord

1980 ◽  
Vol 194 (4) ◽  
pp. 781-807 ◽  
Author(s):  
Stephen Gobel ◽  
William M. Falls ◽  
Gary J. Bennett ◽  
Mohammed Abdelmoumene ◽  
Haruhide Hayashi ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Horseradish Peroxidase ◽  
Islet Cells ◽  
Substantia Gelatinosa ◽  
Synaptic Connections ◽  
Adult Cat

Synaptic connections in a dissociated mixed culture of rat dorsal root ganglion and spinal cord neurons

2006 ◽  
Vol 38 (4) ◽  
pp. 302-304 ◽  
Author(s):  
Yu. O. Kolodin ◽  
A. O. Moskalyuk ◽  
N. S. Veselovsky ◽  
S. A. Fedulova
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglion ◽  
Mixed Culture ◽  
Dorsal Root ◽  
Synaptic Connections ◽  
Spinal Cord Neurons

scholarly journals Nodal GABA facilitates axon spike transmission in the spinal cord

2021 ◽  
Author(s):  
Krishnapriya Hari ◽  
Ana M. Lucas-Osma ◽  
Krista Metz ◽  
Shihao Lin ◽  
Noah Pardell ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Gabaergic Neurons ◽  
Branch Points ◽  
Cutaneous Stimulation ◽  
Inhibitory Neurotransmitter ◽  
Axonal Conduction ◽  
Sensory Axons ◽  
Sensory Transmission ◽  
Excitatory Action ◽  
The Many

SUMMARYGABA is an inhibitory neurotransmitter that produces both postsynaptic and presynaptic inhibition. We describe here an opposing excitatory action of GABA that facilitates spike transmission at nodes of Ranvier in myelinated sensory axons in the spinal cord. This nodal facilitation results from axonal GABAA receptors that depolarize nodes toward threshold, enabling spike propagation past the many branch points that otherwise fail, as observed in spinal cords isolated from mice or rats. Activation of GABAergic neurons, either directly with optogenetics or indirectly with cutaneous stimulation, caused nodal facilitation that increased sensory transmission to motoneurons without postsynaptically exciting motoneurons. This increased transmission with optogenetic or cutaneous stimulation also occurred in awake mice and humans. Optogenetic inhibition of GABAergic neurons decreased sensory transmission, implying that axonal conduction relies on GABA. The concept of nodal facilitation likely generalizes to other large axons in the CNS, enabling recruitment of selective branches and functional pathways.

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