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Kimitaka Nakazawa - One of the best experts on this subject based on the ideXlab platform.
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Muscle-Specific Modulation of Spinal Reflexes in Lower-Limb Muscles during Action Observation with and without Motor Imagery of Walking.
Brain sciences, 2019Co-Authors: Naotsugu Kaneko, Yohei Masugi, Noboru Usuda, Hikaru Yokoyama, Kimitaka NakazawaAbstract:Action observation (AO) and motor imagery (MI) are useful techniques in neurorehabilitation. Previous studies have reported that AO and MI facilitate corticoSpinal excitability only in those muscles that are active when actually performing the observed or imagined movements. However, it remained unclear whether Spinal Reflexes modulate multiple muscles simultaneously. The present study focused on AO and MI of walking and aimed to clarify their effects on Spinal Reflexes in lower-limb muscles that are recruited during actual walking. Ten healthy males participated in the present study. Spinal reflex parameters evoked by transcutaneous Spinal cord stimulation were measured from five lower-limb muscles during rest, AO, and AO combined with MI (AO + MI) conditions. Our results showed that Spinal Reflexes were increased in the tibialis anterior and biceps femoris muscles during AO and in the tibialis anterior, soleus, and medial gastrocnemius muscles during AO + MI, compared with resting condition. Spinal reflex parameters in the vastus medialis muscle were unchanged. These results indicate the muscle-specific modulations of Spinal Reflexes during AO and AO + MI. These findings reveal the underlying neural activities induced by AO, MI, and their combined processes.
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Remote muscle contraction enhances Spinal Reflexes in multiple lower-limb muscles elicited by transcutaneous Spinal cord stimulation
Experimental brain research, 2019Co-Authors: Yohei Masugi, Atsushi Sasaki, Naotsugu Kaneko, Kimitaka NakazawaAbstract:Transcutaneous Spinal cord stimulation (tSCS) is a useful technique for the clinical assessment of neurological disorders. However, the characteristics of the Spinal cord circuits activated by tSCS are not yet fully understood. In this study, we examined whether remote muscle contraction enhances the Spinal Reflexes evoked by tSCS in multiple lower-limb muscles. Eight healthy men participated in the current experiment, which required them to grip a dynamometer as fast as possible after the presentation of an auditory cue. Spinal Reflexes were evoked in multiple lower-limb muscles with different time intervals (50-400 ms) after the auditory signals. The amplitudes of the Spinal Reflexes in all the recorded leg muscles significantly increased at 50-250 ms after remote muscle activation onset. This suggests that remote muscle contraction simultaneously facilitates the Spinal Reflexes in multiple lower-limb muscles. In addition, eight healthy men performed five different tasks (i.e., rest, hand grip, pinch grip, elbow flexion, and shoulder flexion). Compared to control values recorded just before each task, the Spinal Reflexes evoked at 250 ms after the auditory signals were significantly enhanced by the above tasks except for the rest task. This indicates that such facilitatory effects are also induced by remote muscle contractions in different upper-limb areas. The present results demonstrate the existence of a neural interaction between remote upper-limb muscles and Spinal reflex circuits activated by tSCS in multiple lower-limb muscles. The combination of tSCS and remote muscle contraction may be useful for the neurological examination of Spinal cord circuits.
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Repeatability of Spinal Reflexes of lower limb muscles evoked by transcutaneous Spinal cord stimulation.
PloS one, 2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Transcutaneous electrical stimulation is a relatively new technique to evoke Spinal Reflexes in lower limb muscles. The advantage of this technique is that the Spinal reflex responses can be obtained from multiple lower limb muscles simultaneously. However, repeatability of Spinal Reflexes evoked by transcutaneous Spinal cord stimulation between days has not been evaluated. We aimed to examine repeatability of recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation. Recruitment curves of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation of 8 lower limb muscles (i.e., foot, lower leg, and thigh muscles) of 20 males were measured on two consecutive days. To confirm that responses were caused by activation of the sensory fiber, a double-pulse stimulation with 50 ms inter-pulse interval was delivered. Peak-to-peak amplitude of the first response was calculated for each muscle when no response was observed in the second response owing to post-activation depression. For comparison with the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the recruitment curves of the H-reflex amplitude of the soleus of 9 males were measured. Threshold intensity and maximal slope of the recruitment curves were calculated, and inter-day repeatability of the properties was quantified using intraclass correlation coefficients. For the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the intraclass correlation coefficient values of threshold intensity and maximal slope for each muscle ranged from 0.487 to 0.874 and from 0.471 to 0.964, respectively. Regarding the soleus H-reflex, the intraclass correlation coefficients of threshold intensity and maximal slope were 0.936 and 0.751, respectively. The present data showed that repeatability of the recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation in the lower limb was moderate to high. Measurement of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation would be useful for longitudinal neurophysiological studies.
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short term inhibition of Spinal Reflexes in multiple lower limb muscles after neuromuscular electrical stimulation of ankle plantar flexors
Experimental Brain Research, 2019Co-Authors: Yohei Masugi, Hiroki Obata, Atsushi Sasaki, Matija Milosevic, Milos R Popovic, Kimitaka NakazawaAbstract:Neuromuscular electrical stimulation (NMES) of lower limbs elicits muscle contractions through the activation of efferent fibers and concomitant recruitment of afferent fibers, which can modulate excitability of the central nervous system. However, neural mechanisms of NMES and how unilateral stimulation of the soleus affects Spinal Reflexes in multiple lower limb muscles bilaterally remains unknown. Twelve able-bodied participants were recruited, and Spinal reflex excitability changes were tested after four interventions, each applied for 60 s, on the right plantar flexors: (1) motor-level NMES; (2) sensory-level NMES; (3) voluntary contraction; (4) rest. Spinal Reflexes were elicited using single-pulse transcutaneous Spinal cord stimulation applied on the lumbar level of the Spinal cord to evoke bilateral responses in multiple lower limb muscles, while maximum motor response (Mmax) was tested in the soleus by stimulating the posterior tibial nerve. Spinal Reflexes and Mmax before each intervention were compared to immediately after and every 5 min subsequently, for 15 min. Results showed that motor-level NMES inhibited Spinal Reflexes of the soleus and other studied muscles of the ipsilateral leg, but not the contralateral leg (except vastus medialis) for 15 min, while not affecting soleus muscle properties (Mmax). Voluntary contraction effect lasted less than 5 min, while sensory-level NMES and rest did not produce an effect. Short-term Spinal reflex excitability was likely affected because antidromic impulses during motor-level NMES coincided in the Spinal cord with afferent inputs to induce Spinal neuroplasticity, whereas afferent input alone did not produce short-term effects. Such activation of muscles with NMES could reduce spasticity in individuals with neurological impairments.
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Latency of the first response of the Spinal Reflexes.
2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Latency of the first response of the Spinal Reflexes.
Yohei Masugi - One of the best experts on this subject based on the ideXlab platform.
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Muscle-Specific Modulation of Spinal Reflexes in Lower-Limb Muscles during Action Observation with and without Motor Imagery of Walking.
Brain sciences, 2019Co-Authors: Naotsugu Kaneko, Yohei Masugi, Noboru Usuda, Hikaru Yokoyama, Kimitaka NakazawaAbstract:Action observation (AO) and motor imagery (MI) are useful techniques in neurorehabilitation. Previous studies have reported that AO and MI facilitate corticoSpinal excitability only in those muscles that are active when actually performing the observed or imagined movements. However, it remained unclear whether Spinal Reflexes modulate multiple muscles simultaneously. The present study focused on AO and MI of walking and aimed to clarify their effects on Spinal Reflexes in lower-limb muscles that are recruited during actual walking. Ten healthy males participated in the present study. Spinal reflex parameters evoked by transcutaneous Spinal cord stimulation were measured from five lower-limb muscles during rest, AO, and AO combined with MI (AO + MI) conditions. Our results showed that Spinal Reflexes were increased in the tibialis anterior and biceps femoris muscles during AO and in the tibialis anterior, soleus, and medial gastrocnemius muscles during AO + MI, compared with resting condition. Spinal reflex parameters in the vastus medialis muscle were unchanged. These results indicate the muscle-specific modulations of Spinal Reflexes during AO and AO + MI. These findings reveal the underlying neural activities induced by AO, MI, and their combined processes.
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Remote muscle contraction enhances Spinal Reflexes in multiple lower-limb muscles elicited by transcutaneous Spinal cord stimulation
Experimental brain research, 2019Co-Authors: Yohei Masugi, Atsushi Sasaki, Naotsugu Kaneko, Kimitaka NakazawaAbstract:Transcutaneous Spinal cord stimulation (tSCS) is a useful technique for the clinical assessment of neurological disorders. However, the characteristics of the Spinal cord circuits activated by tSCS are not yet fully understood. In this study, we examined whether remote muscle contraction enhances the Spinal Reflexes evoked by tSCS in multiple lower-limb muscles. Eight healthy men participated in the current experiment, which required them to grip a dynamometer as fast as possible after the presentation of an auditory cue. Spinal Reflexes were evoked in multiple lower-limb muscles with different time intervals (50-400 ms) after the auditory signals. The amplitudes of the Spinal Reflexes in all the recorded leg muscles significantly increased at 50-250 ms after remote muscle activation onset. This suggests that remote muscle contraction simultaneously facilitates the Spinal Reflexes in multiple lower-limb muscles. In addition, eight healthy men performed five different tasks (i.e., rest, hand grip, pinch grip, elbow flexion, and shoulder flexion). Compared to control values recorded just before each task, the Spinal Reflexes evoked at 250 ms after the auditory signals were significantly enhanced by the above tasks except for the rest task. This indicates that such facilitatory effects are also induced by remote muscle contractions in different upper-limb areas. The present results demonstrate the existence of a neural interaction between remote upper-limb muscles and Spinal reflex circuits activated by tSCS in multiple lower-limb muscles. The combination of tSCS and remote muscle contraction may be useful for the neurological examination of Spinal cord circuits.
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Repeatability of Spinal Reflexes of lower limb muscles evoked by transcutaneous Spinal cord stimulation.
PloS one, 2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Transcutaneous electrical stimulation is a relatively new technique to evoke Spinal Reflexes in lower limb muscles. The advantage of this technique is that the Spinal reflex responses can be obtained from multiple lower limb muscles simultaneously. However, repeatability of Spinal Reflexes evoked by transcutaneous Spinal cord stimulation between days has not been evaluated. We aimed to examine repeatability of recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation. Recruitment curves of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation of 8 lower limb muscles (i.e., foot, lower leg, and thigh muscles) of 20 males were measured on two consecutive days. To confirm that responses were caused by activation of the sensory fiber, a double-pulse stimulation with 50 ms inter-pulse interval was delivered. Peak-to-peak amplitude of the first response was calculated for each muscle when no response was observed in the second response owing to post-activation depression. For comparison with the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the recruitment curves of the H-reflex amplitude of the soleus of 9 males were measured. Threshold intensity and maximal slope of the recruitment curves were calculated, and inter-day repeatability of the properties was quantified using intraclass correlation coefficients. For the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the intraclass correlation coefficient values of threshold intensity and maximal slope for each muscle ranged from 0.487 to 0.874 and from 0.471 to 0.964, respectively. Regarding the soleus H-reflex, the intraclass correlation coefficients of threshold intensity and maximal slope were 0.936 and 0.751, respectively. The present data showed that repeatability of the recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation in the lower limb was moderate to high. Measurement of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation would be useful for longitudinal neurophysiological studies.
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short term inhibition of Spinal Reflexes in multiple lower limb muscles after neuromuscular electrical stimulation of ankle plantar flexors
Experimental Brain Research, 2019Co-Authors: Yohei Masugi, Hiroki Obata, Atsushi Sasaki, Matija Milosevic, Milos R Popovic, Kimitaka NakazawaAbstract:Neuromuscular electrical stimulation (NMES) of lower limbs elicits muscle contractions through the activation of efferent fibers and concomitant recruitment of afferent fibers, which can modulate excitability of the central nervous system. However, neural mechanisms of NMES and how unilateral stimulation of the soleus affects Spinal Reflexes in multiple lower limb muscles bilaterally remains unknown. Twelve able-bodied participants were recruited, and Spinal reflex excitability changes were tested after four interventions, each applied for 60 s, on the right plantar flexors: (1) motor-level NMES; (2) sensory-level NMES; (3) voluntary contraction; (4) rest. Spinal Reflexes were elicited using single-pulse transcutaneous Spinal cord stimulation applied on the lumbar level of the Spinal cord to evoke bilateral responses in multiple lower limb muscles, while maximum motor response (Mmax) was tested in the soleus by stimulating the posterior tibial nerve. Spinal Reflexes and Mmax before each intervention were compared to immediately after and every 5 min subsequently, for 15 min. Results showed that motor-level NMES inhibited Spinal Reflexes of the soleus and other studied muscles of the ipsilateral leg, but not the contralateral leg (except vastus medialis) for 15 min, while not affecting soleus muscle properties (Mmax). Voluntary contraction effect lasted less than 5 min, while sensory-level NMES and rest did not produce an effect. Short-term Spinal reflex excitability was likely affected because antidromic impulses during motor-level NMES coincided in the Spinal cord with afferent inputs to induce Spinal neuroplasticity, whereas afferent input alone did not produce short-term effects. Such activation of muscles with NMES could reduce spasticity in individuals with neurological impairments.
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Latency of the first response of the Spinal Reflexes.
2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Latency of the first response of the Spinal Reflexes.
Shripad B. Deshpande - One of the best experts on this subject based on the ideXlab platform.
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Involvement of 5-hydroxytryptaminergic transmission for the Mesobuthus tamulus venom-induced depression of Spinal Reflexes in neonatal rat in vitro.
Neuroscience letters, 2010Co-Authors: Amar N. Maurya, Shripad B. DeshpandeAbstract:Mesobuthus tamulus (MBT) venom is shown to depress the Spinal Reflexes through a mechanism unrelated to the NMDA receptors. 5-Hydroxytryptamine (5-HT) is another excitatory transmitter in the Spinal cord therefore, the present study was undertaken to examine the involvement of 5-HT in the venom-induced depression of Reflexes. The experiments were performed on isolated hemisected Spinal cords from 4 to 6-day-old rats. Stimulation of a dorsal root with supramaximal strength evoked monosynaptic reflex (MSR) and polysynaptic reflex (PSR) potentials in the corresponding segmental ventral root. MBT venom (0.3 microg/ml) depressed the Spinal Reflexes in a time-dependent manner and the maximal depression was seen at 10 min. The time to produce 50% depression (T-50) of MSR and PSR was 8.1+/-1.41 and 6.8+/-0.5 min, respectively. Pretreatment with pindolol (1 microM; 5-HT(1A/1B) receptor antagonist) blocked the Reflexes up to 15 min. On the other hand, ketanserin (10 microM; 5-HT(2A/2C) receptor antagonist) or ondansetron (0.1 microM; 5-HT(3) receptor antagonist) blocked the venom-induced depression of MSR and PSR during entire exposure time (30 min). The 5-HT concentration of the cords exposed to venom (1.6+/-0.04 microg/g tissue) was significantly greater than the control group (0.98+/-0.08 microg/g tissue). The results indicate that venom-induced depression of Spinal Reflexes is mediated via 5-HTergic transmission involving 5-HT(1A/1B), 5-HT(2A/2C) and 5-HT(3) receptors.
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Involvement of nitric oxide in 3-nitropropionic acid-induced depression of Spinal Reflexes in neonatal rat Spinal cord in vitro.
European Journal of Pharmacology, 2009Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:Abstract The objective of the present investigation is to study the involvement of nitric oxide (NO) in 3-nitropropionic acid (3-NPA)-induced depression of Spinal Reflexes. Experiments were conducted on preparations of hemisected Spinal cord isolated from 4 to 8 day old rats. Stimulation of a dorsal root evoked reflex potentials (monosynaptic, MSR; polysynaptic, PSR) in the corresponding segmental ventral root. Superfusion of 3-NPA (3.4 mM) depressed the Spinal Reflexes in a time-dependent manner and the Reflexes were abolished after 35 min. The time required to produce 50% depression of the Reflexes (T-50) was 17.8 ± 5.3 min for MSR and 17.5 ± 2.1 min for PSR. L-NAME (Nω-nitro- l -arginine methyl ester; 100 µM), a nitric oxide synthase inhibitor, antagonized the 3-NPA (3.4 mM)-induced depression of Reflexes and increased the T-50 values (34 and 30 min for MSR and PSR, respectively) significantly (P
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Involvement of nitric oxide in 3-nitropropionic acid-induced depression of Spinal Reflexes in neonatal rat Spinal cord in vitro.
European journal of pharmacology, 2009Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:The objective of the present investigation is to study the involvement of nitric oxide (NO) in 3-nitropropionic acid (3-NPA)-induced depression of Spinal Reflexes. Experiments were conducted on preparations of hemisected Spinal cord isolated from 4 to 8 day old rats. Stimulation of a dorsal root evoked reflex potentials (monosynaptic, MSR; polysynaptic, PSR) in the corresponding segmental ventral root. Superfusion of 3-NPA (3.4 mM) depressed the Spinal Reflexes in a time-dependent manner and the Reflexes were abolished after 35 min. The time required to produce 50% depression of the Reflexes (T-50) was 17.8+/-5.3 min for MSR and 17.5+/-2.1 min for PSR. L-NAME (Nomega-nitro-L-arginine methyl ester; 100 microM), a nitric oxide synthase inhibitor, antagonized the 3-NPA (3.4 mM)-induced depression of Reflexes and increased the T-50 values (34 and 30 min for MSR and PSR, respectively) significantly (P
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3-Nitropropionic acid-induced depression of Spinal Reflexes involves mechanisms different from ischemia-induced depression.
Brain research bulletin, 2008Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:Abstract Effect of 3-nitropropionic acid (3-NPA) and ischemia (glucose- and O 2 -free solution) on synaptic transmission in hemisected Spinal cord from 4 to 8 day old rats was examined in vitro . Stimulation of a dorsal root (L3-5 segments) evoked monosynaptic (MSR) and polysynaptic reflex (PSR) potentials in the segmental ventral root. Superfusion of 3-NPA (0.17–3.4 mM) depressed the Reflexes in a concentration- and time-dependent manner. At 3.4 mM of 3-NPA, the Reflexes were abolished by 35 min. Time required to produce 50% depression (T-50) was around 170, 80, 40 and 17 min for MSR and 110, 70, 25 and 16 min for PSR at 0.17, 0.51, 1.7 and 3.4 mM of 3-NPA, respectively. Ischemia also produced a time-dependent depression of Reflexes and abolished them by 35 min and the T-50 values were around 18 min. Presence of creatine phosphate (10 mM) in the superfusing medium did not alter the time course of 3-NPA-induced depression of Reflexes but prolonged the ischemia-induced depression. dl -2-amino-5-phosphonovaleric acid (NMDA receptor antagonist; 10 μM) failed to block the 3-NPA (3.4 mM)-induced depression of Reflexes, but blocked the ischemia-induced depression. The results indicate that 3-NPA-induced depression of Spinal Reflexes does not involve NMDA receptors and is different from ischemia-induced depression.
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3-Nitropropionic acid depresses Spinal Reflexes involving GABAergic and glycinergic transmission in neonatal rat Spinal cord in vitro.
Life sciences, 2008Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:3-Nitropropionic acid (3-NPA) is a naturally occurring fungal toxin that leads to ATP-depletion by inhibiting mitochondrial succinate dehydrogenase and produces chemical anoxia. The present study was conducted to identify the involvement of inhibitory system in 3-NPA-induced depression of Spinal Reflexes. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials were recorded at ventral root by stimulating the corresponding dorsal root in hemisected (sagitally) Spinal cord from 4-8 day old rats. Effect of 3-NPA in the absence and presence of antagonists was evaluated on the Reflexes. Superfusion of 3-NPA (3.4 mM) depressed the Reflexes in a time-dependent manner abolishing them by 35 min. The T-50 values were around 18 and 16 min for MSR and PSR, respectively. An NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid (10 microM) failed to block the 3-NPA (3.4 mM)-induced depression of Reflexes. Superfusion of bicuculline (GABAA receptor antagonist; 1 microM), or strychnine (glycineA receptor antagonist; 1 microM) antagonized the 3-NPA-induced depression of Reflexes significantly. The T-50 values were 26 and 30 min in bicuculline and strychnine pretreated groups, respectively and were significantly greater than 3-NPA only group. The results indicate that 3-NPA-induced depression of Spinal Reflexes is partially mediated by GABAergic and glycinergic inhibitory transmission.
Rajesh Gupta - One of the best experts on this subject based on the ideXlab platform.
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Involvement of nitric oxide in 3-nitropropionic acid-induced depression of Spinal Reflexes in neonatal rat Spinal cord in vitro.
European Journal of Pharmacology, 2009Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:Abstract The objective of the present investigation is to study the involvement of nitric oxide (NO) in 3-nitropropionic acid (3-NPA)-induced depression of Spinal Reflexes. Experiments were conducted on preparations of hemisected Spinal cord isolated from 4 to 8 day old rats. Stimulation of a dorsal root evoked reflex potentials (monosynaptic, MSR; polysynaptic, PSR) in the corresponding segmental ventral root. Superfusion of 3-NPA (3.4 mM) depressed the Spinal Reflexes in a time-dependent manner and the Reflexes were abolished after 35 min. The time required to produce 50% depression of the Reflexes (T-50) was 17.8 ± 5.3 min for MSR and 17.5 ± 2.1 min for PSR. L-NAME (Nω-nitro- l -arginine methyl ester; 100 µM), a nitric oxide synthase inhibitor, antagonized the 3-NPA (3.4 mM)-induced depression of Reflexes and increased the T-50 values (34 and 30 min for MSR and PSR, respectively) significantly (P
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Involvement of nitric oxide in 3-nitropropionic acid-induced depression of Spinal Reflexes in neonatal rat Spinal cord in vitro.
European journal of pharmacology, 2009Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:The objective of the present investigation is to study the involvement of nitric oxide (NO) in 3-nitropropionic acid (3-NPA)-induced depression of Spinal Reflexes. Experiments were conducted on preparations of hemisected Spinal cord isolated from 4 to 8 day old rats. Stimulation of a dorsal root evoked reflex potentials (monosynaptic, MSR; polysynaptic, PSR) in the corresponding segmental ventral root. Superfusion of 3-NPA (3.4 mM) depressed the Spinal Reflexes in a time-dependent manner and the Reflexes were abolished after 35 min. The time required to produce 50% depression of the Reflexes (T-50) was 17.8+/-5.3 min for MSR and 17.5+/-2.1 min for PSR. L-NAME (Nomega-nitro-L-arginine methyl ester; 100 microM), a nitric oxide synthase inhibitor, antagonized the 3-NPA (3.4 mM)-induced depression of Reflexes and increased the T-50 values (34 and 30 min for MSR and PSR, respectively) significantly (P
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3-Nitropropionic acid-induced depression of Spinal Reflexes involves mechanisms different from ischemia-induced depression.
Brain research bulletin, 2008Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:Abstract Effect of 3-nitropropionic acid (3-NPA) and ischemia (glucose- and O 2 -free solution) on synaptic transmission in hemisected Spinal cord from 4 to 8 day old rats was examined in vitro . Stimulation of a dorsal root (L3-5 segments) evoked monosynaptic (MSR) and polysynaptic reflex (PSR) potentials in the segmental ventral root. Superfusion of 3-NPA (0.17–3.4 mM) depressed the Reflexes in a concentration- and time-dependent manner. At 3.4 mM of 3-NPA, the Reflexes were abolished by 35 min. Time required to produce 50% depression (T-50) was around 170, 80, 40 and 17 min for MSR and 110, 70, 25 and 16 min for PSR at 0.17, 0.51, 1.7 and 3.4 mM of 3-NPA, respectively. Ischemia also produced a time-dependent depression of Reflexes and abolished them by 35 min and the T-50 values were around 18 min. Presence of creatine phosphate (10 mM) in the superfusing medium did not alter the time course of 3-NPA-induced depression of Reflexes but prolonged the ischemia-induced depression. dl -2-amino-5-phosphonovaleric acid (NMDA receptor antagonist; 10 μM) failed to block the 3-NPA (3.4 mM)-induced depression of Reflexes, but blocked the ischemia-induced depression. The results indicate that 3-NPA-induced depression of Spinal Reflexes does not involve NMDA receptors and is different from ischemia-induced depression.
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3-Nitropropionic acid depresses Spinal Reflexes involving GABAergic and glycinergic transmission in neonatal rat Spinal cord in vitro.
Life sciences, 2008Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:3-Nitropropionic acid (3-NPA) is a naturally occurring fungal toxin that leads to ATP-depletion by inhibiting mitochondrial succinate dehydrogenase and produces chemical anoxia. The present study was conducted to identify the involvement of inhibitory system in 3-NPA-induced depression of Spinal Reflexes. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials were recorded at ventral root by stimulating the corresponding dorsal root in hemisected (sagitally) Spinal cord from 4-8 day old rats. Effect of 3-NPA in the absence and presence of antagonists was evaluated on the Reflexes. Superfusion of 3-NPA (3.4 mM) depressed the Reflexes in a time-dependent manner abolishing them by 35 min. The T-50 values were around 18 and 16 min for MSR and PSR, respectively. An NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid (10 microM) failed to block the 3-NPA (3.4 mM)-induced depression of Reflexes. Superfusion of bicuculline (GABAA receptor antagonist; 1 microM), or strychnine (glycineA receptor antagonist; 1 microM) antagonized the 3-NPA-induced depression of Reflexes significantly. The T-50 values were 26 and 30 min in bicuculline and strychnine pretreated groups, respectively and were significantly greater than 3-NPA only group. The results indicate that 3-NPA-induced depression of Spinal Reflexes is partially mediated by GABAergic and glycinergic inhibitory transmission.
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3-Nitropropionic acid depresses Spinal Reflexes involving GABAergic and glycinergic transmission in neonatal rat Spinal cord in vitro
Life Sciences, 2008Co-Authors: Rajesh Gupta, Shripad B. DeshpandeAbstract:Abstract Aims 3-Nitropropionic acid (3-NPA) is a naturally occurring fungal toxin that leads to ATP-depletion by inhibiting mitochondrial succinate dehydrogenase and produces chemical anoxia. The present study was conducted to identify the involvement of inhibitory system in 3-NPA-induced depression of Spinal Reflexes. Methods The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials were recorded at ventral root by stimulating the corresponding dorsal root in hemisected (sagitally) Spinal cord from 4–8 day old rats. Effect of 3-NPA in the absence and presence of antagonists was evaluated on the Reflexes. Key findings Superfusion of 3-NPA (3.4 mM) depressed the Reflexes in a time-dependent manner abolishing them by 35 min. The T-50 values were around 18 and 16 min for MSR and PSR, respectively. An NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid (10 μM) failed to block the 3-NPA (3.4 mM)-induced depression of Reflexes. Superfusion of bicuculline (GABA A receptor antagonist; 1 μM), or strychnine (glycine A receptor antagonist; 1 μM) antagonized the 3-NPA-induced depression of Reflexes significantly. The T-50 values were 26 and 30 min in bicuculline and strychnine pretreated groups, respectively and were significantly greater than 3-NPA only group. Significance The results indicate that 3-NPA-induced depression of Spinal Reflexes is partially mediated by GABAergic and glycinergic inhibitory transmission.
Hiroki Obata - One of the best experts on this subject based on the ideXlab platform.
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Repeatability of Spinal Reflexes of lower limb muscles evoked by transcutaneous Spinal cord stimulation.
PloS one, 2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Transcutaneous electrical stimulation is a relatively new technique to evoke Spinal Reflexes in lower limb muscles. The advantage of this technique is that the Spinal reflex responses can be obtained from multiple lower limb muscles simultaneously. However, repeatability of Spinal Reflexes evoked by transcutaneous Spinal cord stimulation between days has not been evaluated. We aimed to examine repeatability of recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation. Recruitment curves of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation of 8 lower limb muscles (i.e., foot, lower leg, and thigh muscles) of 20 males were measured on two consecutive days. To confirm that responses were caused by activation of the sensory fiber, a double-pulse stimulation with 50 ms inter-pulse interval was delivered. Peak-to-peak amplitude of the first response was calculated for each muscle when no response was observed in the second response owing to post-activation depression. For comparison with the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the recruitment curves of the H-reflex amplitude of the soleus of 9 males were measured. Threshold intensity and maximal slope of the recruitment curves were calculated, and inter-day repeatability of the properties was quantified using intraclass correlation coefficients. For the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation, the intraclass correlation coefficient values of threshold intensity and maximal slope for each muscle ranged from 0.487 to 0.874 and from 0.471 to 0.964, respectively. Regarding the soleus H-reflex, the intraclass correlation coefficients of threshold intensity and maximal slope were 0.936 and 0.751, respectively. The present data showed that repeatability of the recruitment properties of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation in the lower limb was moderate to high. Measurement of the Spinal Reflexes evoked by transcutaneous Spinal cord stimulation would be useful for longitudinal neurophysiological studies.
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short term inhibition of Spinal Reflexes in multiple lower limb muscles after neuromuscular electrical stimulation of ankle plantar flexors
Experimental Brain Research, 2019Co-Authors: Yohei Masugi, Hiroki Obata, Atsushi Sasaki, Matija Milosevic, Milos R Popovic, Kimitaka NakazawaAbstract:Neuromuscular electrical stimulation (NMES) of lower limbs elicits muscle contractions through the activation of efferent fibers and concomitant recruitment of afferent fibers, which can modulate excitability of the central nervous system. However, neural mechanisms of NMES and how unilateral stimulation of the soleus affects Spinal Reflexes in multiple lower limb muscles bilaterally remains unknown. Twelve able-bodied participants were recruited, and Spinal reflex excitability changes were tested after four interventions, each applied for 60 s, on the right plantar flexors: (1) motor-level NMES; (2) sensory-level NMES; (3) voluntary contraction; (4) rest. Spinal Reflexes were elicited using single-pulse transcutaneous Spinal cord stimulation applied on the lumbar level of the Spinal cord to evoke bilateral responses in multiple lower limb muscles, while maximum motor response (Mmax) was tested in the soleus by stimulating the posterior tibial nerve. Spinal Reflexes and Mmax before each intervention were compared to immediately after and every 5 min subsequently, for 15 min. Results showed that motor-level NMES inhibited Spinal Reflexes of the soleus and other studied muscles of the ipsilateral leg, but not the contralateral leg (except vastus medialis) for 15 min, while not affecting soleus muscle properties (Mmax). Voluntary contraction effect lasted less than 5 min, while sensory-level NMES and rest did not produce an effect. Short-term Spinal reflex excitability was likely affected because antidromic impulses during motor-level NMES coincided in the Spinal cord with afferent inputs to induce Spinal neuroplasticity, whereas afferent input alone did not produce short-term effects. Such activation of muscles with NMES could reduce spasticity in individuals with neurological impairments.
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Latency of the first response of the Spinal Reflexes.
2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:Latency of the first response of the Spinal Reflexes.
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A typical example of recruitment of Spinal Reflexes evoked by transcutaneous Spinal cord stimulation.
2019Co-Authors: Akira Saito, Yohei Masugi, Kento Nakagawa, Hiroki Obata, Kimitaka NakazawaAbstract:A: Waveforms of Spinal Reflexes at different stimulation intensities from 10 to 100 mA. B: Recruitment curves of Spinal Reflexes between days.
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Influence of motor imagery on Spinal reflex excitability of multiple muscles.
Neuroscience letters, 2018Co-Authors: Kento Nakagawa, Akira Saito, Yohei Masugi, Hiroki Obata, Kimitaka NakazawaAbstract:The effects of motor imagery on Spinal Reflexes such as the H-reflex are unclear. One reason for this is that the muscles that can be used to record Spinal Reflexes are limited to traditional evoking methods Recently, transcutaneous Spinal cord stimulation has been used for inducing Spinal Reflexes from multiple muscles and we aimed to examine the effect of motor imagery on Spinal Reflexes from multiple muscles. Spinal Reflexes evoked by transcutaneous Spinal cord stimulation were recorded from six muscles from lower limbs during motor imagery of right wrist extension and ankle plantarflexion with maximum isometric contraction. During both imaginary tasks, facilitation of Spinal Reflexes was detected in the ankle ipsilateral plantarflexor and dorsiflexor muscles, but not in thigh, toe or contralateral lower limb muscles. These results suggest that motor imagery of isometric contraction facilitates Spinal reflex excitability in muscles of the ipsilateral lower leg and the facilitation does not correspond to the imaginary involved muscles.
