The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Kaoru Takakusaki - One of the best experts on this subject based on the ideXlab platform.
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brainstem control of locomotion and muscle tone with special reference to the role of the mesopontine tegmentum and medullary reticulospinal systems
Journal of Neural Transmission, 2016Co-Authors: Kaoru Takakusaki, Ryosuke Chiba, Tsukasa Nozu, Toshikatsu OkumuraAbstract:The lateral part of the mesopontine tegmentum contains functionally important structures involved in the control of posture and gait. Specifically, the mesencephalic locomotor region, which may consist of the Cuneiform Nucleus and pedunculopontine tegmental Nucleus (PPN), occupies the interest with respect to the pathophysiology of posture-gait disorders. The purpose of this article is to review the mechanisms involved in the control of postural muscle tone and locomotion by the mesopontine tegmentum and the pontomedullary reticulospinal system. To make interpretation and discussion more robust, the above issue is considered largely based on our findings in the experiments using decerebrate cat preparations in addition to the results in animal experimentations and clinical investigations in other laboratories. Our investigations revealed the presence of functional topographical organizations with respect to the regulation of postural muscle tone and locomotion in both the mesopontine tegmentum and the pontomedullary reticulospinal system. These organizations were modified by neurotransmitter systems, particularly the cholinergic PPN projection to the pontine reticular formation. Because efferents from the forebrain structures as well as the cerebellum converge to the mesencephalic and pontomedullary reticular formation, changes in these organizations may be involved in the appropriate regulation of posture-gait synergy depending on the behavioral context. On the other hand, abnormal signals from the higher motor centers may produce dysfunction of the mesencephalic-reticulospinal system. Here we highlight the significance of elucidating the mechanisms of the mesencephalic-reticulospinal control of posture and locomotion so that thorough understanding of the pathophysiological mechanisms of posture-gait disorders can be made.
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basal ganglia efferents to the brainstem centers controlling postural muscle tone and locomotion a new concept for understanding motor disorders in basal ganglia dysfunction
Neuroscience, 2003Co-Authors: Kaoru Takakusaki, Tatsuya Habaguchi, J Ohtinatasugimoto, Kazuya Saitoh, Takashi SakamotoAbstract:The present study is designed to elucidate how basal ganglia afferents from the substantia nigra pars reticulata (SNr) to the mesopontine tegmental area of the brainstem contribute to gait control and muscle-tone regulation. We used unanesthetized and acutely decerebrated cats (n=27) in which the striatum, thalamus and cerebral cortex were removed but the SNr was preserved. Repetitive stimulation (50 Hz, 10–60 μA, for 5–20 s) applied to a mesencephalic locomotor region (MLR), which corresponded to the Cuneiform Nucleus, and adjacent areas, evoked locomotor movements. On the other hand, stimulation of a muscle-tone inhibitory region in the pedunculopontine tegmental Nucleus (PPN) suppressed postural muscle tone. An injection of either glutamatergic agonists (N-methyl-d-aspartic acid and kainic acid) or GABA antagonists (bicuculline and picrotoxin) into the MLR and PPN also induced locomotion and muscle-tone suppression, respectively. Repetitive electrical stimuli (50–100 Hz, 20–60 μA for 5–20 s) delivered to the SNr alone did not alter muscular activity. However stimulating the lateral part of the SNr attenuated and blocked PPN-induced muscle-tone suppression. Moreover, weaker stimulation of the medial part of the SNr reduced the number of step cycles and disturbed the rhythmic alternation of limb movements of MLR-induced locomotion. The onset of locomotion was delayed as the stimulus intensity was increased. At a higher strength SNr stimulation abolished the locomotion. An injection of bicuculline into either the PPN or the MLR diminished the SNr effects noted above. These results suggest that locomotion and postural muscle tone are subject to modulation by GABAergic nigrotegmental projections which have a partial functional topography: a lateral and medial SNr, for regulation of postural muscle tone and locomotion, respectively. We conclude that disorders of the basal ganglia may include dysfunction of the nigrotegmental (basal ganglia–brainstem) systems, which consequently leads to the production of abnormal muscle tone and gait disturbance.
Caroline Sevozcouche - One of the best experts on this subject based on the ideXlab platform.
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rostral Cuneiform Nucleus and the defence reaction direct and indirect midbrain medullary 5 ht mechanisms in baroreflex inhibition
British Journal of Pharmacology, 2021Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:Background and purpose Activation of the defence reaction inhibits the baroreflex response via the intermediate rostro-ventromedial medulla (B3 raphe) and Nucleus tractus solitarius (NTS). Our aim was to determine whether and how baroreflex inhibition, induced by the disinhibition of the rostral Cuneiform Nucleus (part of the defence pathway), involves 5-HT neurons in B3 and 5-HT3 receptors in the NTS. Experimental approach We performed immunohistochemistry and anatomical experiments to determine whether raphe 5-HT cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe 5-HT neurotransmission and NTS 5-HT3 receptors on Cuneiform-induced inhibition of the baroreflex cardiac response were also analysed. Key results Bicuculline, microinjected into the rostral Cuneiform Nucleus, induced an increase of double-labelled Fos-5-HT-IR cells in both the lateral paragigantocellular Nucleus (LPGi) and raphe magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin injected into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not raphe magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a selective 5-HT1A receptor agonist. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after NTS microinjection of the 5-HT3 receptor antagonist granisetron and in 5-HT3 receptor knockout mice. Conclusion and implications The rostral Cuneiform Nucleus participates in the defence inhibition of the baroreflex bradycardia via direct activation of the LPGi and via a projection to the raphe magnus to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
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rostral Cuneiform Nucleus and the defense reaction direct and indirect midbrain medullary serotonin mechanisms in baroreflex inhibition
British Journal of Pharmacology, 2021Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:BACKGROUND AND PURPOSE Activation of the defence reaction inhibits the baroreflex response via the intermediate rostro-ventromedial medulla (B3 raphe) and Nucleus tractus solitarius (NTS). Our aim was to determine whether and how baroreflex inhibition, induced by the disinhibition of the rostral Cuneiform Nucleus (part of the defence pathway), involves 5-HT neurons in B3 and 5-HT3 receptors in the NTS. EXPERIMENTAL APPROACH We performed immunohistochemistry and anatomical experiments to determine whether raphe 5-HT cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe 5-HT neurotransmission and NTS 5-HT3 receptors on Cuneiform-induced inhibition of the baroreflex cardiac response were also analysed. KEY RESULTS Bicuculline, microinjected into the rostral Cuneiform Nucleus, induced an increase of double-labelled Fos-5-HT-IR cells in both the lateral paragigantocellular Nucleus (LPGi) and raphe magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin injected into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not raphe magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a selective 5-HT1A receptor agonist. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after NTS microinjection of the 5-HT3 receptor antagonist granisetron and in 5-HT3 receptor knockout mice. CONCLUSION AND IMPLICATIONS The rostral Cuneiform Nucleus participates in the defence inhibition of the baroreflex bradycardia via direct activation of the LPGi and via a projection to the raphe magnus to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
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rostral Cuneiform Nucleus and the defense reaction direct and indirect midbrain medullary serotonin mechanisms in baroreflex inhibition
Authorea Preprints, 2020Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:Background and Purpose: The activation of the defense reaction inhibits the baroreflex response through the B3 and Nucleus tractus solitarius (NTS) regions. Our aim was to determine whether and how baroreflex inhibition induced by the disinhibition of the rostral Cuneiform Nucleus, part of the defense pathway, involves serotonin cells in B3 and 5-HT3 receptors in the NTS. Experimental Approach: We performed immunohistochemistry and anatomical experiments to determine whether raphe serotonin cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe serotonin transmission and NTS 5-HT3 receptors, on Cuneiform-induced inhibition of the baroreflex cardiac response, were also analyzed. Key Results: Bicuculline microinjected into the rostral Cuneiform Nucleus induced an increase of double labeled Fos-5-HT IR cells in both the LPGi and Raphe Magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not Raphe Magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a specific agonist for 5-HT1A receptors. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after microinjection of a 5-HT3 receptor antagonist (granisetron) into the NTS or in 5-HT3 receptor knock-out mice. Conclusion and Implications: In conclusion, the rostral Cuneiform Nucleus participates in the defense inhibition of the baroreflex bradycardia via direct activation of the LPGi and a relay to the Raphe Magnus, to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
Takashi Sakamoto - One of the best experts on this subject based on the ideXlab platform.
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basal ganglia efferents to the brainstem centers controlling postural muscle tone and locomotion a new concept for understanding motor disorders in basal ganglia dysfunction
Neuroscience, 2003Co-Authors: Kaoru Takakusaki, Tatsuya Habaguchi, J Ohtinatasugimoto, Kazuya Saitoh, Takashi SakamotoAbstract:The present study is designed to elucidate how basal ganglia afferents from the substantia nigra pars reticulata (SNr) to the mesopontine tegmental area of the brainstem contribute to gait control and muscle-tone regulation. We used unanesthetized and acutely decerebrated cats (n=27) in which the striatum, thalamus and cerebral cortex were removed but the SNr was preserved. Repetitive stimulation (50 Hz, 10–60 μA, for 5–20 s) applied to a mesencephalic locomotor region (MLR), which corresponded to the Cuneiform Nucleus, and adjacent areas, evoked locomotor movements. On the other hand, stimulation of a muscle-tone inhibitory region in the pedunculopontine tegmental Nucleus (PPN) suppressed postural muscle tone. An injection of either glutamatergic agonists (N-methyl-d-aspartic acid and kainic acid) or GABA antagonists (bicuculline and picrotoxin) into the MLR and PPN also induced locomotion and muscle-tone suppression, respectively. Repetitive electrical stimuli (50–100 Hz, 20–60 μA for 5–20 s) delivered to the SNr alone did not alter muscular activity. However stimulating the lateral part of the SNr attenuated and blocked PPN-induced muscle-tone suppression. Moreover, weaker stimulation of the medial part of the SNr reduced the number of step cycles and disturbed the rhythmic alternation of limb movements of MLR-induced locomotion. The onset of locomotion was delayed as the stimulus intensity was increased. At a higher strength SNr stimulation abolished the locomotion. An injection of bicuculline into either the PPN or the MLR diminished the SNr effects noted above. These results suggest that locomotion and postural muscle tone are subject to modulation by GABAergic nigrotegmental projections which have a partial functional topography: a lateral and medial SNr, for regulation of postural muscle tone and locomotion, respectively. We conclude that disorders of the basal ganglia may include dysfunction of the nigrotegmental (basal ganglia–brainstem) systems, which consequently leads to the production of abnormal muscle tone and gait disturbance.
Hongbing Xiang - One of the best experts on this subject based on the ideXlab platform.
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the caudal pedunculopontine tegmental Nucleus may be involved in the regulation of skeletal muscle activity by melanocortin sympathetic pathway a virally mediated trans synaptic tracing study in spinally transected transgenic mice
Oncotarget, 2017Co-Authors: Baowen Liu, Xuebi Tian, Sanguang Liu, Anne Manyande, Dingyu Zhang, Hongbing XiangAbstract:Understanding neuroanatomical sympathetic circuitry and neuronal connections from the caudal pedunculopontine tegmental Nucleus to skeletal muscle is important to the study of possible mechanisms of pedunculopontine tegmental Nucleus (PPTg) and Cuneiform Nucleus (CnF) that are involved in the regulation of skeletal muscle activity of the sympathetic pathway. The aim of this study was to use virus PRV-614 to trace the melanocortin-sympathetic neural pathways from PPTg and CnF to a hindlimb muscle (gastrocnemius) in spinally transected MC4R-GFP transgenic mice. PRV-614 was injected into the gastrocnemius muscle after receiving a complete spinal cord transection below the L2 level. PRV-614/MC4R-GFP and PRV-614/TPH dual-labeled neurons were found in the dissipated parts of PPTg (dpPPTg), but not between the compact parts of PPTg (cpPPTg) and CnF. It is proposed that a hierarchical pathway of neurons within the caudal pedunculopontine tegmental Nucleus sends projections to the RVLM, which in turn projects onto the IML sympathetic preganglionic neurons that regulate muscle blood flow through melanocortin-sympathetic signals. Our results collectively indicate that MC4Rs expressed in caudal pedunculopontine tegmental Nucleus may be involved in skeletal muscle activity of melanocortin-sympathetic pathways.
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the Cuneiform Nucleus may be involved in the regulation of skeletal muscle tone by motor pathway a virally mediated trans synaptic tracing study in surgically sympathectomized mice
Brain, 2013Co-Authors: Hongbing Xiang, Xuehai Guan, Dawei YeAbstract:ARTICLE Sir, The review article entitled ‘The pedunculopontine Nucleus area: critical evaluation of interspecies differences relevant for its use as a target for deep brain stimulation’ by Alam et al. (2011), addressed that the Cuneiform Nucleus, an adjacent region of the pedunculopontine Nucleus, was the important area of the mesencephalic locomotor region and played a major role in the initiation of gait. It has been suggested by many studies that neurons in the Cuneiform Nucleus are involved in the generation of locomotion, and signals from the Cuneiform Nucleus activate central pattern generators in the spinal cord, mainly through the medullary reticulospinal tract (Takakusaki et al. , 2003). The understanding of neuroanatomical motor circuitry and neuronal connections from Cuneiform Nucleus to skeletal muscle is important for studying the possible mechanism of Cuneiform Nucleus involved in the regulation of skeletal muscle tone by motor pathway. We would like to further complete the discussion of Alam et al. (2011) by introducing a virally-mediated trans-synaptic tracing study. Deep brain stimulation has become a remarkable treatment option for several different movement disorders, such as neuropsychiatric disorders, intractable pain, epilepsy, restless legs syndrome, Parkinson’s disease, and Alzheimer’s disease (Wichmann and Delong, 2006; Halpern et al. , 2007; Lyons, 2011; Thevathasan et al. , 2011). The mesencephalic pedunculopontine tegmental Nucleus has been suggested as a target for deep brain stimulation, but the exact mechanism of deep brain stimulation in the pedunculopontine tegmental Nucleus area is not fully understood. Because clinical data have demonstrated that the outcome of deep brain stimulation in the pedunculopontine Nucleus area can be quite variable, there is great controversy about the …
Florence Netzer - One of the best experts on this subject based on the ideXlab platform.
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rostral Cuneiform Nucleus and the defence reaction direct and indirect midbrain medullary 5 ht mechanisms in baroreflex inhibition
British Journal of Pharmacology, 2021Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:Background and purpose Activation of the defence reaction inhibits the baroreflex response via the intermediate rostro-ventromedial medulla (B3 raphe) and Nucleus tractus solitarius (NTS). Our aim was to determine whether and how baroreflex inhibition, induced by the disinhibition of the rostral Cuneiform Nucleus (part of the defence pathway), involves 5-HT neurons in B3 and 5-HT3 receptors in the NTS. Experimental approach We performed immunohistochemistry and anatomical experiments to determine whether raphe 5-HT cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe 5-HT neurotransmission and NTS 5-HT3 receptors on Cuneiform-induced inhibition of the baroreflex cardiac response were also analysed. Key results Bicuculline, microinjected into the rostral Cuneiform Nucleus, induced an increase of double-labelled Fos-5-HT-IR cells in both the lateral paragigantocellular Nucleus (LPGi) and raphe magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin injected into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not raphe magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a selective 5-HT1A receptor agonist. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after NTS microinjection of the 5-HT3 receptor antagonist granisetron and in 5-HT3 receptor knockout mice. Conclusion and implications The rostral Cuneiform Nucleus participates in the defence inhibition of the baroreflex bradycardia via direct activation of the LPGi and via a projection to the raphe magnus to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
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rostral Cuneiform Nucleus and the defense reaction direct and indirect midbrain medullary serotonin mechanisms in baroreflex inhibition
British Journal of Pharmacology, 2021Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:BACKGROUND AND PURPOSE Activation of the defence reaction inhibits the baroreflex response via the intermediate rostro-ventromedial medulla (B3 raphe) and Nucleus tractus solitarius (NTS). Our aim was to determine whether and how baroreflex inhibition, induced by the disinhibition of the rostral Cuneiform Nucleus (part of the defence pathway), involves 5-HT neurons in B3 and 5-HT3 receptors in the NTS. EXPERIMENTAL APPROACH We performed immunohistochemistry and anatomical experiments to determine whether raphe 5-HT cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe 5-HT neurotransmission and NTS 5-HT3 receptors on Cuneiform-induced inhibition of the baroreflex cardiac response were also analysed. KEY RESULTS Bicuculline, microinjected into the rostral Cuneiform Nucleus, induced an increase of double-labelled Fos-5-HT-IR cells in both the lateral paragigantocellular Nucleus (LPGi) and raphe magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin injected into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not raphe magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a selective 5-HT1A receptor agonist. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after NTS microinjection of the 5-HT3 receptor antagonist granisetron and in 5-HT3 receptor knockout mice. CONCLUSION AND IMPLICATIONS The rostral Cuneiform Nucleus participates in the defence inhibition of the baroreflex bradycardia via direct activation of the LPGi and via a projection to the raphe magnus to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
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rostral Cuneiform Nucleus and the defense reaction direct and indirect midbrain medullary serotonin mechanisms in baroreflex inhibition
Authorea Preprints, 2020Co-Authors: Florence Netzer, Caroline SevozcoucheAbstract:Background and Purpose: The activation of the defense reaction inhibits the baroreflex response through the B3 and Nucleus tractus solitarius (NTS) regions. Our aim was to determine whether and how baroreflex inhibition induced by the disinhibition of the rostral Cuneiform Nucleus, part of the defense pathway, involves serotonin cells in B3 and 5-HT3 receptors in the NTS. Experimental Approach: We performed immunohistochemistry and anatomical experiments to determine whether raphe serotonin cells expressing Fos were directly targeted by the rostral Cuneiform Nucleus. The effect of blocking raphe serotonin transmission and NTS 5-HT3 receptors, on Cuneiform-induced inhibition of the baroreflex cardiac response, were also analyzed. Key Results: Bicuculline microinjected into the rostral Cuneiform Nucleus induced an increase of double labeled Fos-5-HT IR cells in both the LPGi and Raphe Magnus. The anterograde tracer Phaseolus vulgaris leucoaggutinin into the rostral Cuneiform Nucleus revealed a dense projection to the LPGi but not Raphe Magnus. Cuneiform-induced baroreflex inhibition was prevented by B3 injection of 8-OH-DPAT, a specific agonist for 5-HT1A receptors. Cuneiform disinhibition also failed to inhibit the baroreflex bradycardia after microinjection of a 5-HT3 receptor antagonist (granisetron) into the NTS or in 5-HT3 receptor knock-out mice. Conclusion and Implications: In conclusion, the rostral Cuneiform Nucleus participates in the defense inhibition of the baroreflex bradycardia via direct activation of the LPGi and a relay to the Raphe Magnus, to activate NTS 5-HT3 receptors and inhibit second-order baroreflex neurons. These data bring new insights in primary and secondary mechanisms involved in vital baroreflex prevention during stress.
