Reflex responses of the spinal cord under conditions of the spinal “superreflexia” evoked by pharmacological agents increasing its excitability

2000 ◽  
Vol 32 (2) ◽  
pp. 92-98 ◽  
Author(s):  
E. A. Makii ◽  
P. A. Nerush ◽  
A. G. rodinskii
Keyword(s):  
Spinal Cord ◽  
Pharmacological Agents ◽  
Reflex Responses

scholarly journals Cutaneous inputs from perineal region facilitates and modulates spinal locomotor activity and reduces cutaneous reflexes from the foot in spinal cats

2020 ◽  
Author(s):  
Angèle N Merlet ◽  
Jonathan Harnie ◽  
Madalina Macovei ◽  
Adam Doelman ◽  
Nathaly Gaudreault ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Nerve Stimulation ◽  
Rhythmic Activity ◽  
Short Latency ◽  
Cutaneous Reflexes ◽  
Excitatory Effect ◽  
Reflex Responses ◽  
Cutaneous Reflex ◽  
Weight Support ◽  
Perineal Region

AbstractIt is well known that mechanically stimulating the perineal region potently facilitates hindlimb locomotion and weight support in mammals with a spinal transection (spinal mammals). However, how perineal stimulation mediates this excitatory effect is poorly understood. We evaluated the effect of mechanically stimulating (vibration or pinch) the perineal region on ipsilateral (9-14 ms onset) and contralateral (14-18 ms onset) short-latency cutaneous reflex responses evoked by electrically stimulating the superficial peroneal or distal tibial nerve in seven adult spinal cats where hindlimb movement was restrained. Cutaneous reflexes were evoked before, during, and after mechanical stimulation of the perineal region. We found that vibration or pinch of the perineal region effectively triggered rhythmic activity, unilateral and bilateral to nerve stimulation. When electrically stimulating nerves, adding perineal stimulation modulated rhythmic activity by decreasing cycle and burst durations and by increasing the amplitude of flexors and extensors. Perineal stimulation also disrupted the timing of the ipsilateral rhythm, which had been entrained by nerve stimulation. Mechanically stimulating the perineal region decreased ipsilateral and contralateral short-latency reflex responses evoked by cutaneous inputs, a phenomenon we observed in muscles crossing different joints and located in different limbs. The results suggest that the excitatory effect of perineal stimulation on locomotion and weight support is not mediated by increasing cutaneous reflex gain and instead points to an excitation of central pattern-generating circuitry. Our results are consistent with a state-dependent modulation of reflexes by spinal interneuronal circuits.Significance StatementMechanically stimulating the skin of the perineal region strongly facilitates hindlimb locomotion in mammals following a complete spinal cord injury (SCI). Despite its remarkable effectiveness in promoting hindlimb locomotion in spinal cord-injured mammals, we do not know how this is mediated. The present study provides data on how inputs from the perineal region interact with neuronal circuits that generate locomotor-like activity and reflexes from the foot. A better understanding of how inputs from the perineal region interact with neuronal circuits of the spinal cord could lead to non-invasive approaches to restore walking in people with SCI.

scholarly journals A Systematic Review of the Effects of Pharmacological Agents on Walking Function in People with Spinal Cord Injury

2012 ◽  
Vol 29 (5) ◽  
pp. 865-879 ◽  
Author(s):  
Antoinette Domingo ◽  
Abdulaziz A. Al-Yahya ◽  
Yousif Asiri ◽  
Janice J. Eng ◽  
Tania Lam, and Spinal Cord Injury Rehabil
Keyword(s):  
Systematic Review ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Pharmacological Agents ◽  
Cord Injury

scholarly journals Spinal nociceptin mediates electroacupuncture-related modulation of visceral sympathoexcitatory reflex responses in rats

2009 ◽  
Vol 297 (2) ◽  
pp. H859-H865 ◽  
Author(s):  
Wei Zhou ◽  
Aman Mahajan ◽  
John C. Longhurst
Keyword(s):  
Spinal Cord ◽  
Receptor Antagonist ◽  
Intrathecal Injection ◽  
Inhibitory Effect ◽  
Ventrolateral Medulla ◽  
Gastric Distension ◽  
Reflex Modulation ◽  
Reflex Responses ◽  
Pressor Responses ◽  
Pressor Reflex

The role of nociceptin and its spinal cord neural pathways in electroacupuncture (EA)-related inhibition of visceral excitatory reflexes is not clear. Nociceptin/orphanin FQ (N/OFQ) is an endogenous ligand for a G protein-coupled receptor, called the N/OFQ peptide (NOP) receptor, which has been found to be distributed in the spinal cord. The present study investigated the importance of this system in visceral-cardiovascular reflex modulation during EA. Cardiovascular pressor reflex responses were induced by gastric distension in Sprague-Dawley rats anesthetized by ketamine and xylazine. An intrathecal injection of nociceptin (10 nM) at T1–2 attenuated the pressor responses by 35%, similar to the influence of EA at P 5–6 (42% decrease). An intrathecal injection of the NOP antagonist, [ N-Phe1]nociceptin1-13 NH2, partially reversed the EA response. Pretreatment with the opioid receptor antagonist naloxone did not alter the EA-like inhibitory effect of nociceptin on the pressor reflex, whereas a combination of nociceptin receptor antagonist with naloxone completely abolished the EA response. An intrathecal injection of nociceptin attenuated the pressor responses to the electrical stimulation of the rostral ventrolateral medulla by 46%, suggesting that nociceptin can regulate sympathetic outflow. Furthermore, a bilateral microinjection of NOP antagonist into either the dorsal horn or the intermediolateral column at T1 partially reversed the EA inhibitory effect. These results suggest that nociceptin in the spinal cord mediates part of the EA-related modulation of visceral reflex responses.

scholarly journals Electrophysiological biomarkers of neuromodulatory strategies to recover motor function after spinal cord injury

2015 ◽  
Vol 113 (9) ◽  
pp. 3386-3396 ◽  
Author(s):  
Parag Gad ◽  
Roland R. Roy ◽  
Jaehoon Choe ◽  
Jack Creagmile ◽  
Hui Zhong ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Control ◽  
Evoked Potentials ◽  
Motor Performance ◽  
Weight Bearing ◽  
Chronic Administration ◽  
Pharmacological Agents ◽  
Extensor Muscles ◽  
Cord Injury ◽  
Complete Paralysis

The spinal cord contains the circuitry to control posture and locomotion after complete paralysis, and this circuitry can be enabled with epidural stimulation [electrical enabling motor control (eEmc)] and/or administration of pharmacological agents [pharmacological enabling motor control (fEmc)] when combined with motor training. We hypothesized that the characteristics of the spinally evoked potentials after chronic administration of both strychnine and quipazine under the influence of eEmc during standing and stepping can be used as biomarkers to predict successful motor performance. To test this hypothesis we trained rats to step bipedally for 7 wk after paralysis and characterized the motor potentials evoked in the soleus and tibialis anterior (TA) muscles with the rats in a non-weight-bearing position, standing and stepping. The middle responses (MRs) to spinally evoked stimuli were suppressed with either or both drugs when the rat was suspended, whereas the addition of either or both drugs resulted in an overall activation of the extensor muscles during stepping and/or standing and reduced the drag duration and cocontraction between the TA and soleus muscles during stepping. The administration of quipazine and strychnine in concert with eEmc and step training after injury resulted in larger-amplitude evoked potentials [MRs and late responses (LRs)] in flexors and extensors, with the LRs consisting of a more normal bursting pattern, i.e., randomly generated action potentials within the bursts. This pattern was linked to more successful standing and stepping. Thus it appears that selected features of the patterns of potentials evoked in specific muscles with stimulation can serve as effective biomarkers and predictors of motor performance.

scholarly journals Medical Treatment in Spinal Cord Injury

2021 ◽  
Author(s):  
Halil Can ◽  
Eyüp Cab Savrunlu ◽  
Serdar Kabataş
Keyword(s):  
Spinal Cord ◽  
Large Scale ◽  
Spinal Cord Injuries ◽  
Controlled Clinical Trials ◽  
Pharmacological Agents ◽  
Randomized Controlled Clinical Trials ◽  
Randomized Controlled ◽  
Secondary Damage ◽  
Cord Injury ◽  
Neurological Progression

Spinal cord injuries cause psychological in humans and require expensive care and treatments. In recent years, various pharmacological agents have been tested in acute spinal cord injuries. Prospective randomized controlled clinical trials on a large scale have failed to demonstrate significant neurological progression, in contrast to their success in the laboratory. The search for an effective neuroprotective pharmacological agent to prevent secondary damage in acute spinal cord injuries remains primary goals for basic sciences and clinicians.

scholarly journals Role of Endogenous Release of Norepinephrine in Muscle Spasms After Chronic Spinal Cord Injury

2007 ◽  
Vol 97 (5) ◽  
pp. 3166-3180 ◽  
Author(s):  
Michelle M. Rank ◽  
Xiaole Li ◽  
David J. Bennett ◽  
Monica A. Gorassini
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Persistent Inward Currents ◽  
Reflex Responses ◽  
Cord Injury ◽  
Inward Currents ◽  
Presynaptic Release ◽  
Endogenous Release

The recovery of persistent inward currents (PICs) and motoneuron excitability after chronic spinal cord transection is mediated, in part, by the development of supersensitivity to residual serotonin (5HT) below the lesion. The purpose of this paper is to investigate if, like 5HT, endogenous sources of norepinephrine (NE) facilitate motoneuron PICs after chronic spinal transection. Cutaneous-evoked reflex responses in tail muscles of awake chronic spinal rats were measured after increasing presynaptic release of NE by administration of amphetamine. An increase in long-lasting reflexes, known to be mediated by the calcium component of the PIC (CaPIC), was observed even at low doses (0.1–0.2 mg/kg) of amphetamine. These findings were repeated in a reduced S2 in vitro preparation, demonstrating that the increased long-lasting reflexes by amphetamine were neural. Under intracellular voltage clamp, amphetamine application led to a large facilitation of the motoneuron CaPIC. This indicates that the increases in long-lasting reflexes induced by amphetamine in the awake animal were, in part, due to actions directly on the motoneuron. Reflex responses in acutely spinal animals were facilitated by amphetamine similar to chronic animals but only at doses that were ten times greater than that required in chronic animals (0.2 mg/kg chronic vs. 2.0 mg/kg acute), pointing to a development of supersensitivity to endogenous NE in chronic animals. In summary, the increases in long-lasting reflexes and associated motoneuron CaPICs by amphetamine are likely due to an increased release of endogenous NE, which motoneurons become supersensitive to in the chronic stages of spinal cord injury.

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