scholarly journals Windup of Nociceptive Flexion Reflex Depends on Synaptic and Intrinsic Properties of Dorsal Horn Neurons in Adult Rats

2019 ◽  
Vol 20 (24) ◽  
pp. 6146
Author(s):  
Franck Aby ◽  
Rabia Bouali-Benazzouz ◽  
Marc Landry ◽  
Pascal Fossat
Keyword(s):  
Spinal Cord ◽  
Progressive Increase ◽  
Ventral Horn ◽  
Intrinsic Properties ◽  
Adult Rats ◽  
Juvenile Rats ◽  
Calcium Dependent ◽  
Nociceptive Flexion Reflex

Windup, a progressive increase in spinal response to repetitive stimulations of nociceptive peripheral fibers, is a useful model to study central sensitization to pain. Windup is expressed by neurons in both the dorsal and ventral horn of the spinal cord. In juvenile rats, it has been demonstrated both in vivo and in vitro that windup depends on calcium-dependent intrinsic properties and their modulation by synaptic components. However, the involvement of these two components in the adults remains controversial. In the present study, by means of electromyographic and extracellular recordings, we show that windup in adults, in vivo, depends on a synaptic balance between excitatory N-methyl-D-aspartate (NMDA) receptors and inhibitory glycinergic receptors. We also demonstrate the involvement of L-type calcium channels in both the dorsal and ventral horn of the spinal cord. These results indicate that windup in adults is similar to juvenile rats and that windup properties are the same regardless of the spinal network, i.e., sensory or motor.

scholarly journals Windup of Nociceptive Flexion Reflex Depends on Synaptic and Intrinsic Properties of Dorsal Horn Neurons in Adult Rat

2019 ◽  
Author(s):  
Franck Aby ◽  
Rabia Bouali-Benazzouz ◽  
Marc Landry ◽  
Pascal Fossat
Keyword(s):  
Spinal Cord ◽  
Progressive Increase ◽  
Ventral Horn ◽  
Intrinsic Properties ◽  
Calcium Dependent ◽  
Adult Rat ◽  
Dorsal Horn Neurons ◽  
Nociceptive Flexion Reflex

Windup, a progressive increase in spinal response to repetitive stimulations of nociceptive peripheral fibres, is a useful model to study central sensitization to pain. Windup is expressed by neurons in of both dorsal and ventral horn of the spinal cord. In juvenile rats, it has been demonstrated both in vivo and in vitro that windup depends on calcium-dependent intrinsic properties and their modulation by synaptic components. However, the involvement of these two components in the adult remain controversial. In the present study, by means of electromyographic and extracellular recordings, we show that windup in adult, in vivo, depends on a synaptic balance between excitatory NMDA receptors and inhibitory glycinergic receptors. We also demonstrate the involvement of L-type calcium channels in both the dorsal and ventral horn of the spinal cord. These results indicate that windup in adults is similar to juveniles rats and that windup properties are the same regardless spinal network, i.e. sensory or motor.

Intrinsic Properties Shape the Firing Pattern of Ventral Horn Interneurons From the Spinal Cord of the Adult Turtle

2006 ◽  
Vol 96 (5) ◽  
pp. 2670-2677 ◽  
Author(s):  
Morten Smith ◽  
Jean-François Perrier
Keyword(s):  
Spinal Cord ◽  
Activity Patterns ◽  
Ventral Horn ◽  
Inward Rectification ◽  
Intrinsic Properties ◽  
Patch Clamp Technique ◽  
Firing Patterns ◽  
Pharmacological Tests ◽  
Low Threshold

Interneurons in the ventral horn of the spinal cord play a central role in motor control. In adult vertebrates, their intrinsic properties are poorly described because of the lack of in vitro preparations from the spinal cord of mature mammals. Taking advantage of the high resistance to anoxia in the adult turtle, we used a slice preparation from the spinal cord. We used the whole cell blind patch-clamp technique to record from ventral horn interneurons. We characterized their firing patterns in response to depolarizing current pulses and found that all the interneurons fired repetitively. They displayed bursting, adapting, delayed, accelerating, or oscillating firing patterns. By combining electrophysiological and pharmacological tests, we showed that interneurons expressed slow inward rectification, plateau potential, voltage-sensitive transient outward rectification, and low-threshold spikes. These results demonstrate a diversity of intrinsic properties that may enable a rich repertoire of activity patterns in the network of ventral horn interneurons.

scholarly journals An In Vitro Protocol for Recording From Spinal Motoneurons of Adult Rats

2008 ◽  
Vol 100 (1) ◽  
pp. 474-481 ◽  
Author(s):  
Jonathan S. Carp ◽  
Ann M. Tennissen ◽  
Donna L. Mongeluzi ◽  
Christopher J. Dudek ◽  
Xiang Yang Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Action Potential ◽  
Mechanical Stability ◽  
Pharmacological Study ◽  
Input Resistance ◽  
Spinal Motoneurons ◽  
Adult Rats ◽  
Precise Control

In vitro slice preparations of CNS tissue are invaluable for studying neuronal function. However, up to now, slice protocols for adult mammal spinal motoneurons—the final common pathway for motor behaviors—have been available for only limited portions of the spinal cord. In most cases, these preparations have not been productive due to the poor viability of motoneurons in vitro. This report describes and validates a new slice protocol that for the first time provides reliable intracellular recordings from lumbar motoneurons of adult rats. The key features of this protocol are: preexposure to 100% oxygen; laminectomy prior to perfusion; anesthesia with ketamine/xylazine; embedding the spinal cord in agar prior to slicing; and, most important, brief incubation of spinal cord slices in a 30% solution of polyethylene glycol to promote resealing of the many motoneuron dendrites cut during sectioning. Together, these new features produce successful recordings in 76% of the experiments and an average action potential amplitude of 76 mV. Motoneuron properties measured in this new slice preparation (i.e., voltage and current thresholds for action potential initiation, input resistance, afterhyperpolarization size and duration, and onset and offset firing rates during current ramps) are comparable to those recorded in vivo. Given the mechanical stability and precise control over the extracellular environment afforded by an in vitro preparation, this new protocol can greatly facilitate electrophysiological and pharmacological study of these uniquely important neurons and other delicate neuronal populations in adult mammals.

Effect of estradiol and tamoxifen on GnRH self-priming in perifused rat adenohypophysial cells

1989 ◽  
Vol 121 (3) ◽  
pp. 365-373 ◽  
Author(s):  
Patricia O. Cover ◽  
Julia C. Buckingham
Keyword(s):  
Estrogen Receptor ◽  
Receptor Antagonist ◽  
Progressive Increase ◽  
Ovariectomized Rats ◽  
Pituitary Cells ◽  
Adult Rats ◽  
Juvenile Rats ◽  
Estrogen Receptor Antagonist ◽  
Rat Pituitary Cells

Abstract. Columns of enzymatically dispersed rat pituitary cells have been used to examine the effects of estradiol and the estrogen receptor antagonist, tamoxifen, on the responsiveness of the gonadotropes to repeated challenges with GnRH. Synthetic GnRH stimulated readily the release of LH from the pituitary cells. When challenged repeatedly with the same submaximal dose (8 nmol/1) of the releasing hormone, cells from animals in diestrus 2 or pro-estrus, like those from juvenile rats, showed a marked progressive increase in their sensitivity, but those from rats in estrus or diestrus 1 did not. Adenohypophysial cells removed from adult rats ovariectomized 14 days previously also failed to exhibit sensitization even when estradiol-17β (1 and 10 nmol/1) was included in the perifusion fluid. However, those from ovariectomized rats treated with appropriate doses of the steroid (1.5 μg/day sc for 14 days or 5 μg sc 22 h before decapitation) did. The capacity of pituitary cells from intact rats to exhibit priming on the anticipated day of pro-estrus was unaffected by the administration of the estrogen receptor antagonist, tamoxifen (700 μg/100 g sc on the morning of diestrus 1 and 24 h later). Similarly, addition of tamoxifen (1 μmol/1) to the incubation medium failed to influence the capacity of pituitary cells from juvenile rats to exhibit priming in vitro. The results support the concept that the ability of GnRH to 'prime' the gonadotropes is dependent on estradiol and indicate that the exposure of the hypothalamo-pituitary complex to critical levels of estradiol prior to autopsy is necessary for the gonadotropes to retain their capacity to exhibit priming in vitro.

Abstract 15601: On the Mechanisms of Accelerated Calcification of Bioprosthetic Heart Valve Biomaterials in Juvenile Animal Models

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yingfei Xue ◽  
Alexander Kossar ◽  
Gaetano THIENE ◽  
Robert LEVY ◽  
Giovanni Ferrari
Keyword(s):  
Pediatric Patients ◽  
Calcium Deposition ◽  
Collagen Structure ◽  
Adult Rats ◽  
Rat Serum ◽  
Juvenile Rats ◽  
Adult Rat ◽  
Circulating Markers

Objective: Bioprosthetic heart valves (BHV) are subject to accelerated structural valve degeneration (SVD) in pediatric patients. Prior literature has reported differences in circulating markers of mineralization in pediatric patients compared to adults. Here we test the hypothesis that calcification-related circulating markers are differentially expressed in juvenile vs adult animals, and these markers functionally drive the accelerated SVD in juvenile animals in vitro and in vivo . Methods: Serum calcium (Ca 2+ ), phosphate (PO 4 - ), alkaline phosphatase (ALP), and osteopontin (OPN) levels of juvenile (3 week-old; n=5) and adult (8 month-old; n=5) Sprague-Dawley rats were measured by commercially-available assay kits. Glutaraldehyde-fixed bovine pericardial discs (BP) were incubated in juvenile or adult rat serum in vitro for 4 or 8 weeks. BP were subcutaneously implanted in juvenile or adult rats for 7 or 30 days (4-6 discs/rat). Pericardial transcatheter valves were implanted in juvenile Dorset sheep for 150 days (n=3). Alizarin Red staining, Von Kossa staining, and a quantitative assay were used for calcium analyses. Second harmonic generation imaging visualized collagen structure. Results: Serum Ca 2+ (p<0.05), PO 4 - (p<0.05), ALP (p<0.01), and OPN (p<0.01) were all increased in juvenile rats compared to adult rats. BP incubated in juvenile rat serum resulted in higher calcium deposition (p<0.05) and more disruption to collagen structure as evidenced by reduced alignment coefficient (p<0.01) as compared to those incubated in adult rat serum. Similarly, BP explanted from juvenile rats had higher calcium deposition (p<0.01) and more disrupted collagen structure in terms of collagen alignment and crimp period (p<0.01). Results in progress in juvenile sheep implantation model further confirmed the in vitro and in vivo findings that BHV explants had substantial calcium deposition and collagen disalignment. Conclusion: Calcium accumulates within BHV biomaterials more prominently in juvenile rats; increased serum markers of mineralization may explain the increased susceptibility to SVD in pediatric patients. Future studies will investigate novel strategies for the prevention and mitigation of accelerated SVD in pediatric patients.

scholarly journals A Collagen-Based Scaffold for Promoting Neural Plasticity in a Rat Model of Spinal Cord Injury

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2245
Author(s):  
Jue-Zong Yeh ◽  
Ding-Han Wang ◽  
Juin-Hong Cherng ◽  
Yi-Wen Wang ◽  
Gang-Yi Fan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Rat Model ◽  
Neural Plasticity ◽  
Collagen Scaffold ◽  
Glial Scar ◽  
Beneficial Effects ◽  
Cord Injury

In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate environment in an SCI rat model and determined whether neural plasticity can be manipulated using this approach. We used four experimental groups, as follows: SCI-collagen scaffold, SCI control, normal spinal cord-collagen scaffold, and normal control. The collagen scaffold showed excellent in vitro and in vivo biocompatibility. Immunofluorescence staining revealed increased expression of neurofilament and fibronectin and reduced expression of glial fibrillary acidic protein and anti-chondroitin sulfate in the collagen scaffold-treated SCI rats at 1 and 4 weeks post-implantation compared with that in untreated SCI control. This indicates that the collagen scaffold implantation promoted neuronal survival and axonal growth within the injured site and prevented glial scar formation by controlling astrocyte production for their normal functioning. Our study highlights the feasibility of using the collagen scaffold in SCI repair. The collagen scaffold was found to exert beneficial effects on neuronal activity and may help in manipulating synaptic plasticity, implying its great potential for clinical application in SCI.

scholarly journals Apoptosis in metanephric development.

1992 ◽  
Vol 119 (5) ◽  
pp. 1327-1333 ◽  
Author(s):  
C Koseki ◽  
D Herzlinger ◽  
Q al-Awqati
Keyword(s):  
Spinal Cord ◽  
Protein Kinase ◽  
Transcriptional Activation ◽  
Phorbol Esters ◽  
Dna Degradation ◽  
Morphological Evidence ◽  
Metanephric Mesenchyme ◽  
Embryonic Spinal Cord

During metanephric development, non-polarized mesenchymal cells are induced to form the epithelial structures of the nephron following interaction with extracellular matrix proteins and factors produced by the inducing tissue, ureteric bud. This induction can occur in a transfilter organ culture system where it can also be produced by heterologous cells such as the embryonic spinal cord. We found that when embryonic mesenchyme was induced in vitro and in vivo, many of the cells surrounding the new epithelium showed morphological evidence of programmed cell death (apoptosis) such as condensed nuclei, fragmented cytoplasm, and cell shrinking. A biochemical correlate of apoptosis is the transcriptional activation of a calcium-sensitive endonuclease. Indeed, DNA isolated from uninduced mesenchyme showed progressive degradation, a process that was prevented by treatment with actinomycin-D or cycloheximide and by buffering intracellular calcium. These results demonstrate that the metanephric mesenchyme is programmed for apoptosis. Incubation of mesenchyme with a heterologous inducer, embryonic spinal cord prevented this DNA degradation. To investigate the mechanism by which inducers prevented apoptosis we tested the effects of protein kinase C modulators on this process. Phorbol esters mimicked the effects of the inducer and staurosporine, an inhibitor of this protein kinase, prevented the effect of the inducer. EGF also prevented DNA degradation but did not lead to differentiation. These results demonstrate that conversion of mesenchyme to epithelial requires at least two steps, rescue of the mesenchyme from apoptosis and induction of differentiation.

scholarly journals Immunosuppressants Affect Human Neural Stem Cells In Vitro but Not in an In Vivo Model of Spinal Cord Injury

2013 ◽  
Vol 2 (10) ◽  
pp. 731-744 ◽  
Author(s):  
Christopher J. Sontag ◽  
Hal X. Nguyen ◽  
Noriko Kamei ◽  
Nobuko Uchida ◽  
Aileen J. Anderson ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Stem Cells ◽  
Spinal Cord Injury ◽  
Neural Stem Cells ◽  
In Vivo Model ◽  
Human Neural Stem Cells ◽  
Cord Injury

scholarly journals Depolarization and electrical stimulation enhance in vitro and in vivo sensory axon growth after spinal cord injury

2018 ◽  
Vol 300 ◽  
pp. 247-258 ◽  
Author(s):  
Ioana Goganau ◽  
Beatrice Sandner ◽  
Norbert Weidner ◽  
Karim Fouad ◽  
Armin Blesch
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Electrical Stimulation ◽  
Axon Growth ◽  
Sensory Axon ◽  
Cord Injury

scholarly journals In vitro analysis of the origin and maintenance of O-2Aadult progenitor cells.

1992 ◽  
Vol 116 (1) ◽  
pp. 167-176 ◽  
Author(s):  
D Wren ◽  
G Wolswijk ◽  
M Noble
Keyword(s):  
Adult Life ◽  
Cell Types ◽  
Adult Rats ◽  
Optic Nerves ◽  
Limited Life ◽  
Old Rats ◽  
Vitro Analysis

We have been studying the differing characteristics of oligodendrocyte-type-2 astrocyte (O-2A) progenitors isolated from optic nerves of perinatal and adult rats. These two cell types display striking differences in their in vitro phenotypes. In addition, the O-2Aperinatal progenitor population appears to have a limited life-span in vivo, while O-2Aadult progenitors appear to be maintained throughout life. O-2Aperinatal progenitors seem to have largely disappeared from the optic nerve by 1 mo after birth, and are not detectable in cultures derived from optic nerves of adult rats. In contrast, O-2Aadult progenitors can first be isolated from optic nerves of 7-d-old rats and are still present in optic nerves of 1-yr-old rats. These observations raise two questions: (a) From what source do O-2Aadult progenitors originate; and (b) how is the O-2Aadult progenitor population maintained in the nerve throughout life? We now provide in vitro evidence indicating that O-2Aadult progenitors are derived directly from a subpopulation of O-2Aperinatal progenitors. We also provide evidence indicating that O-2Aadult progenitors are capable of prolonged self renewal in vitro. In addition, our data suggests that the in vitro generation of oligodendrocytes from O-2Aadult progenitors occurs primarily through asymmetric division and differentiation, in contrast with the self-extinguishing pattern of symmetric division and differentiation displayed by O-2Aperinatal progenitors in vitro. We suggest that O-2Aadult progenitors express at least some properties of stem cells and thus may be able to support the generation of both differentiated progeny cells as well as their own continued replenishment throughout adult life.

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