Development of specific muscle and cutaneous sensory projections in cultured segments of spinal cord

Development ◽  
1994 ◽  
Vol 120 (5) ◽  
pp. 1315-1323 ◽  
Author(s):  
K. Sharma ◽  
Z. Korade ◽  
E. Frank
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Muscle Afferents ◽  
Cutaneous Afferents ◽  
In Ovo ◽  
Sensory Afferents ◽  
Chicken Embryos ◽  
Sensory Projections ◽  
Spinal Segments ◽  
Horn Development

Development of sensory projections was studied in cultured spinal segments with attached dorsal root ganglia. In spinal segments from stage 30 (E6.5) and older chicken embryos, prelabeled muscle and cutaneous afferents established appropriate projections. Cutaneous afferents terminated solely within the dorsolateral laminae, whereas some muscle afferents (presumably Ia afferents) projected ventrally towards motoneurons. Development of appropriate projections suggests that sufficient cues are preserved in spinal segments to support the formation of modality-specific sensory projections. Further, because these projections developed in the absence of muscle or skin, these results show that the continued presence of peripheral targets is not required for the formation of specific central projections after stage 29 (E6.0). Development of the dorsal horn in cultured spinal segments was assessed using the dorsal midline as a marker. In ovo, this midline structure appears at stage 29. Lack of midline formation in stage 28 and 29 cultured spinal segments suggests that the development of the dorsal horn is arrested in this preparation. This is consistent with earlier reports suggesting that dorsal horn development may be dependent on factors outside the spinal cord. Because dorsal horn development is blocked in cultured spinal segments, this preparation makes it possible to study the consequences of premature ingrowth of sensory axons into the spinal cord. In chicken embryos sensory afferents reach the spinal cord at stage 25 (E4.5) but do not arborize within the gray matter until stage 30. During this period dorsal horn cells are still being generated. In spinal segments, only those segments that have developed a midline at the time of culture support the formation of midline at the time of culture support the formation of specific sensory projections.(ABSTRACT TRUNCATED AT 250 WORDS)

Attenuation of reflex pressor and ventilatory responses to static contraction by an NK-1 receptor antagonist

1992 ◽  
Vol 73 (4) ◽  
pp. 1389-1395 ◽  
Author(s):  
J. M. Hill ◽  
J. G. Pickar ◽  
M. P. Kaufman
Keyword(s):  
Spinal Cord ◽  
Substance P ◽  
Receptor Antagonist ◽  
Dorsal Horn ◽  
Intrathecal Injection ◽  
Muscular Contraction ◽  
Muscle Afferents ◽  
Neurokinin A ◽  
Ventilatory Responses ◽  
Static Contraction

The chemical messengers released onto second-order dorsal horn neurons from the spinal terminals of contraction-activated group III and IV muscle afferents have not been identified. One candidate is the tachykinin substance P. Related to substance P are two other tachykinins, neurokinin A (NKA) and neurokinin B (NKB), which, like substance P, have been isolated in the dorsal horn of the spinal cord and have receptors there. Whether NKA or NKB plays a transmitter/modulator role in the spinal processing of the exercise pressor reflex is unknown. Therefore, we tested the following hypotheses. After the intrathecal injection of a highly selective NK-1 (substance P) receptor antagonist onto the lumbosacral spinal cord, the reflex pressor and ventilatory responses to static muscular contraction will be attenuated. Likewise, after the intrathecal injection either of an NK-2 (NKA) receptor antagonist or an NK-3 (NKB) receptor antagonist onto the lumbrosacral spinal cord, the reflex pressor and ventilatory responses to static contraction will be attenuated. We found that, 10 min after the intrathecal injection of 100 micrograms of the NK-1 receptor antagonist, the pressor and ventilatory responses to contraction were significantly (P < 0.05) attenuated. Mean arterial pressure was attenuated by 13 +/- 3 mmHg (48%) and minute volume of ventilation by 120 +/- 38 ml/min (34%). The cardiovascular and ventilatory responses to contraction before either 100 micrograms of the NK-2 receptor antagonist or 100 micrograms of the NK-3 receptor antagonist were not different (P > 0.05) from those after the NK-2 or the NK-3 receptor antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Comprehensive phenotyping of group III and IV muscle afferents in mouse

2013 ◽  
Vol 109 (9) ◽  
pp. 2374-2381 ◽  
Author(s):  
Michael P. Jankowski ◽  
Kristofer K. Rau ◽  
Katrina M. Ekmann ◽  
Collene E. Anderson ◽  
H. Richard Koerber
Keyword(s):  
Spinal Cord ◽  
Functional Properties ◽  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Receptor Potential ◽  
Muscle Afferents ◽  
Transient Receptor Potential Vanilloid ◽  
Sensory Afferents ◽  
Group Iii ◽  
Concentration Levels

While much is known about the functional properties of cutaneous nociceptors, relatively little is known about the comprehensive functional properties of group III and IV muscle afferents. We have developed a mouse ex vivo forepaw muscle, median and ulnar nerve, dorsal root ganglion (DRG), spinal cord recording preparation to examine the functional response properties, neurochemical phenotypes, and spinal projections of individual muscle afferents. We found that the majority of group III and IV muscle afferents were chemosensitive (52%) while only 34% responded to mechanical stimulation and fewer (32%) responded to thermal stimuli. The chemosensitive afferents could be grouped into those that responded to a “low”-metabolite mixture containing amounts of lactate and ATP at pH 7.0 simulating levels observed in muscle during exercise (metaboreceptors) and a “high”-metabolite mixture containing lactic acid concentrations and ATP at pH 6.6 mimicking levels observed during ischemic contractions (metabo-nociceptors). While the majority of the metabo-nociceptive fibers responding to the higher concentration levels were found to contain acid-sensing ion channel 3 (ASIC3) and/or transient receptor potential vanilloid type 1 (TRPV1), metaboreceptors responding to the lower concentration levels lacked these receptors. Anatomically, group III muscle afferents were found to have projections into laminae I and IIo, and deeper laminae in the spinal cord, while all functional types of group IV muscle afferents projected primarily into both laminae I and II. These results provide novel information about the variety of sensory afferents innervating the muscle and provide insight into the types of fibers that may exhibit plasticity after injuries.

c-Fos induction in spinal cord neurons after renal arterial or venous occlusion

1999 ◽  
Vol 276 (1) ◽  
pp. R120-R127 ◽  
Author(s):  
M. Patricia Rosas-Arellano ◽  
L. Pastor Solano-Flores ◽  
John Ciriello
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Renal Nerve ◽  
Spinal Cord Neurons ◽  
Afferent Fibers ◽  
Distinct Cluster ◽  
Dorsal Horns ◽  
Spinal Segments

Experiments were done in the anesthetized rat to identify the dorsal root ganglia (DRG) and the spinal cord segments that contain neurons activated by either renal venous occlusion (RVO) or by renal arterial occlusion (RAO). Fos induction, detected immunohistochemically in DRG and the spinal cord neurons, was used as a marker for neuronal activation. RVO induced Fos immunoreactivity in neurons in the DRG of spinal segments T8-L2on the side ipsilateral to that of occlusion. The largest number of Fos-labeled neurons was found in the T11 DRG. In the spinal cord the largest number of Fos-labeled neurons was found in the ipsilateral dorsal horn of spinal segments T11-T12, predominantly in a cluster near the dorsomedial edge of laminae I-II. A few additional Fos-labeled neurons were observed in laminae IV and V. After RAO Fos-labeled neurons were found in the ipsilateral DRG of spinal segments similar to those observed to contain neurons after RVO. However, most of the Fos-labeled neurons were observed within the T12-L1DRG. In the spinal cord Fos-labeled neurons were scattered throughout lamina I-II of the ipsilateral dorsal horn of spinal segments T8-L2, although the largest number was observed at the T13 level. Additionally, a distinct cluster of Fos-labeled neurons was observed predominantly in the region of the ipsilateral intermediolateral cell column, although a few neurons were found scattered throughout the nucleus intercalatus, central autonomic areas, and laminae IV and V of the cord bilaterally. No Fos labeling was observed in the complementary contralateral DRG or dorsal horns after either RVO or RAO. In addition, renal nerve transection prevented Fos labeling in the ipsilateral DRG and dorsal horns after RVO or RAO. Taken together, these data suggest that functionally different renal afferent fibers activate DRG neurons that may have distinct projections in the spinal cord.

scholarly journals Epidural Electrical Stimulation Of The Cervical Dorsal Roots Restores Voluntary Arm Control In Paralyzed Monkeys

2021 ◽  
Author(s):  
Marco Capogrosso ◽  
Beatrice Barra ◽  
Sara Conti ◽  
Matthew Perich ◽  
Katie Zhuang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Functional Organization ◽  
Three Dimensional ◽  
Spinal Reflexes ◽  
Neural Function ◽  
Sensory Afferents ◽  
Dorsal Roots ◽  
Cord Injury ◽  
Spinal Segments

Abstract Recovering arm control is a top priority for people with paralysis. Unfortunately, the complexity of the neural mechanisms underlying arm control practically limited the effectiveness of neurotechnology approaches. Here, we exploited the neural function of surviving spinal circuits to restore voluntary arm and hand control in three monkeys with spinal cord injury using spinal cord stimulation. Our neural interface leverages the functional organization of the dorsal roots to convey artificial excitation via electrical stimulation to relevant spinal segments at appropriate movement phases. Stimulation bursts, triggered by intracortical signals produced sustained arm movements enabling monkeys with arm paralysis to perform an unconstrained, three-dimensional reach-and-grasp task. Stimulation specifically improved strength, task performances and movement quality. Electrophysiology suggested that artificial recruitment of the sensory afferents was synergistically integrated with spared descending inputs and spinal reflexes to produce coordinated movements. The efficacy and reliability of our approach hold realistic promises of clinical translation.

scholarly journals Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hyun Joon Lee ◽  
Patrick S. Malone ◽  
Jumi Chung ◽  
Jason M. White ◽  
Natalee Wilson ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cutaneous Afferents ◽  
Spinal Level ◽  
Central Projections ◽  
Reflex Responses ◽  
Somatotopic Organization ◽  
C Fibers ◽  
Cord Injury ◽  
Spinal Segments

Electrical stimulations of dorsal cutaneous nerves (DCNs) at each lumbothoracic spinal level produce the bilateral cutaneus trunci muscle (CTM) reflex responses which consist of two temporal components: an early and late responses purportedly mediated by Aδ and C fibers, respectively. We have previously reported central projections of DCN A and C fibers and demonstrated that different projection patterns of those afferent types contributed to the somatotopic organization of CTM reflex responses. Unilateral hemisection spinal cord injury (SCI) was made at T10 spinal segments to investigate the plasticity of early and late CTM responses 6 weeks after injury. Both early and late responses were drastically increased in response to both ipsi- and contralateral DCN stimulations both above (T6 and T8) and below (T12 and L1) the levels of injury demonstrating that nociceptive hyperreflexia developed at 6 weeks following hemisection SCI. We also found that DCN A and C fibers centrally sprouted, expanded their projection areas, and increased synaptic terminations in both T7 and T13, which correlated with the size of hemisection injury. These data demonstrate that central sprouting of cutaneous afferents away from the site of injury is closely associated with enhanced responses of intraspinal signal processing potentially contributing to nociceptive hyperreflexia following SCI.

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