The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
Hiroshi Onimaru - One of the best experts on this subject based on the ideXlab platform.
-
the effects of lidocaine on central Respiratory Neuron activity and nociceptive related responses in the brainstem spinal cord preparation of the newborn rat
Anesthesia & Analgesia, 2016Co-Authors: Tomoharu Shakuo, Shihtien Lin, Hiroshi OnimaruAbstract:BACKGROUND Lidocaine is widely used in the clinical setting as a local anesthetic and antiarrhythmic drug. Although it has been suggested that lidocaine exerts inhibitory effects on the central and peripheral Neurons, there are no reports on its effects on central Respiratory activity in vertebrates. In this study, we examined the effects of lidocaine on Respiratory rhythm generation and nociceptive response in brainstem-spinal cord preparations from the newborn rats. METHODS Preparations were isolated from Wistar rats (postnatal day 0-3) and superfused with artificial cerebrospinal fluid equilibrated with 95% O2 and 5% CO2, pH 7.4, at 25°C to 26°C. We examined the effects of lidocaine on the fourth cervical ventral root (C4)-inspiratory activity and on the preinspiratory and inspiratory Neurons in the rostral medulla. We also examined the effects on the C4/C5 reflex responses induced by ipsilateral C7/C8 dorsal root stimulation, which are thought to be related to the nociceptive response. RESULTS The application of low doses of lidocaine (10-20 μM) resulted in a slight increase of the C4 burst rate, whereas high doses of lidocaine (100-400 μM) decreased the burst rate in a dose-dependent manner, eventually resulting in the complete cessation of Respiratory rhythm. High doses of lidocaine decreased the burst duration and negative slope conductance of preinspiratory Neurons, suggesting that lidocaine blocked persistent Na+ current. After the burst generation of the Respiratory Neurons ceased, depolarizing current stimulation continued to induce action potentials; however, the induction of the spike train was depressed because of strong adaptation. A low dose of lidocaine (20 μM) depressed C4/C5 spinal reflex responses. CONCLUSIONS Our findings indicate that lidocaine depressed nociception-related responses at lower concentrations than those that induced Respiratory depression. Our report provides the basic Neuronal mechanisms to support the clinical use of lidocaine, which shows antinociceptive effects with minimal side effects on breathing.
-
visualization of Respiratory Neuron activity in the ventral medulla from a newborn rodent
2006Co-Authors: Hiroshi Onimaru, Akiko Arata, Satoru Arata, Ikuo HommaAbstract:We visualized Respiratory Neuron network activity in the medulla of the rat and mouse in vitro by optical recordings using voltage-sensitive dye. The brainstem and spinal cord of 0- to 1-day-old Wistar rats and 0-day-old mice isolated under deep ether anaesthesia were incubated in a modified Krebs solution containing a fluorescent voltage-sensitive dye. Fluorescence signals corresponding to Respiratory activity were detected by a CCD image sensor. Pre-inspiratory Neuron activity appeared in the limited region of the rostral ventrolateral medulla [i.e. para-facial Respiratory group (pFRG) region], preceding the onset of inspiratory activity by about 500 ms. During the inspiratory phase, plateau activity appeared in the more caudal ventrolateral medulla at the level of most rostral roots of the XIIth nerve (i.e. the pre-Botzinger complex level). We found that pre-inspiratory Neurons which were a predominant subtype of the pFRG Neurons were located in the area immediately beneath the ventral pia mater at the level of the facial nucleus. We also analyzed Respiratory Neuron activity in the wild type and two kinds of knock-out mice that exhibit Respiratory failure leading to neonatal death due to dysfunction of central Respiratory Neuron activity. The optical recordings clearly detected the difference in the spatio-temporal pattern between the wild type and both knockout mice.
-
Optical imaging of Respiratory Neuron activity from the dorsal view of the lower brainstem
Clinical and Experimental Pharmacology and Physiology, 2005Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:1. We visualized Respiratory-related Neuron network activity in the dorsal part of the pons and medulla of an in vitro preparation from newborn rats by optical recordings using a voltage-sensitive dye. We measured optical signals from several seconds before to several seconds after the inspiratory phase using the inspiratory motor nerve discharge as the trigger signal and we averaged the optical signals of 20-50 Respiratory cycles to obtain an optical image correlating specifically to inspiratory activity. 2. Four areas that were excited or inhibited corresponding to the Respiratory cycles were detected. (i) The most rostral activity was in the rostral and lateral parts of the pons, with activity mainly in the inspiratory phase, corresponding to the pontine-Respiratory group. (ii) In the midpontine level, inspiratory activity followed by long-lasting hyperpolarization appeared in the midlateral parts. This part was presumed to reflect activity in the locus coeruleus. The hyperpolarization became almost negligible after treatment with the alpha-adrenergic antagonist, phentolamine. (iii) In the dorsal medulla, the predominantly inspiratory activity was detected at the rostral level of the area postrema. This part was considered to reflect activity mainly of the hypoglossal nucleus. (iv) At a similar level, we also detected weak and disperse inspiratory activity extending more laterally and caudally than that of the hypoglossal nucleus activity. This might reflect activity of the dorsal Respiratory group. 3. In conclusion, the present optical recording study revealed that the dorsal part of the lower brainstem in the in vitro preparation is noticeably active as well as the ventral part shown in the previous study. This method is very useful for analysis of pharmacological properties, as well as the spatio-temporal pattern of Respiratory-related network activity in the brainstem.
-
developmental changes in the spatio temporal pattern of Respiratory Neuron activity in the medulla of late fetal rat
Neuroscience, 2005Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:We investigated how the spatio-temporal pattern of Respiratory Neuron network activity in the ventral medulla changes during the late fetal period of rat. Brainstem-spinal cord preparations isolated from rat fetuses on embryonic days 17-21 (E17-E21) were stained with a voltage-sensitive dye for optical image analysis of Neuronal activity of the ventral medulla. The spatio-temporal pattern of Respiratory Neuron activity in the preparation from E20 to E21 was basically identical to that of neonatal rat; pre-inspiratory activity in a limited region of the rostral ventrolateral medulla, the para-facial region, preceded by several hundred milliseconds the onset of inspiratory activity in the more caudal ventrolateral medulla, the pre-Botzinger complex level. In contrast, in E17-E18 specimens, pre-inspiratory activity could not be detected in the rostral medulla at the level of the facial nucleus. Neuronal activity appeared to begin at the pre-Botzinger complex level shortly before onset of the inspiratory burst. Strong activity then developed in the facial nucleus and peaked in the post-inspiratory phase. The transition of these patterns of Respiratory activity occurred at E19. We conclude that the changes in the spatio-temporal pattern of Neuronal activity reflect developmental changes in the cellular elements underlying rhythm generation in the fetal Respiratory Neuron network. We suggest that the pre-inspiratory Neuron network of the para-facial region in the rostral ventrolateral medulla functions as the rhythm generator after E19/20.
-
in vitro visualization of Respiratory Neuron activity in the newborn mouse ventral medulla
Developmental Brain Research, 2004Co-Authors: Hiroshi Onimaru, Akiko Arata, Satoru Arata, Senji Shirasawa, Michael L ClearyAbstract:Abstract To clarify the Neuronal organization of the Respiratory center of the mouse, we analyzed the spatio-temporal pattern of Respiratory Neuron activity in the ventral medulla of a newborn mouse preparation, using optical recordings. We also demonstrated optical images of the Respiratory activity of two different lines of knock-out mice ( Tlx3 −/− , Pbx3 −/− ) that exhibit Respiratory failure leading to neonatal death from dysfunction of central Respiratory Neuron activity. In the wild type mice, the Respiratory Neuron activity in the para-facial region of the rostral medulla appeared prior to inspiratory activity in the more caudal ventrolateral medulla. This rostral to caudal activity pattern was basically preserved in Tlx3 −/− mice though the activity was more dispersed and weaker than in the wild type mice. Such an activity pattern was not clearly detected in Pbx3 −/− mouse preparations. The difference in the spatio-temporal pattern between Tlx3 −/− and Pbx3 −/− suggests different levels of functional disorder of the Respiratory center.
Ikuo Homma - One of the best experts on this subject based on the ideXlab platform.
-
visualization of Respiratory Neuron activity in the ventral medulla from a newborn rodent
2006Co-Authors: Hiroshi Onimaru, Akiko Arata, Satoru Arata, Ikuo HommaAbstract:We visualized Respiratory Neuron network activity in the medulla of the rat and mouse in vitro by optical recordings using voltage-sensitive dye. The brainstem and spinal cord of 0- to 1-day-old Wistar rats and 0-day-old mice isolated under deep ether anaesthesia were incubated in a modified Krebs solution containing a fluorescent voltage-sensitive dye. Fluorescence signals corresponding to Respiratory activity were detected by a CCD image sensor. Pre-inspiratory Neuron activity appeared in the limited region of the rostral ventrolateral medulla [i.e. para-facial Respiratory group (pFRG) region], preceding the onset of inspiratory activity by about 500 ms. During the inspiratory phase, plateau activity appeared in the more caudal ventrolateral medulla at the level of most rostral roots of the XIIth nerve (i.e. the pre-Botzinger complex level). We found that pre-inspiratory Neurons which were a predominant subtype of the pFRG Neurons were located in the area immediately beneath the ventral pia mater at the level of the facial nucleus. We also analyzed Respiratory Neuron activity in the wild type and two kinds of knock-out mice that exhibit Respiratory failure leading to neonatal death due to dysfunction of central Respiratory Neuron activity. The optical recordings clearly detected the difference in the spatio-temporal pattern between the wild type and both knockout mice.
-
Optical imaging of Respiratory Neuron activity from the dorsal view of the lower brainstem
Clinical and Experimental Pharmacology and Physiology, 2005Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:1. We visualized Respiratory-related Neuron network activity in the dorsal part of the pons and medulla of an in vitro preparation from newborn rats by optical recordings using a voltage-sensitive dye. We measured optical signals from several seconds before to several seconds after the inspiratory phase using the inspiratory motor nerve discharge as the trigger signal and we averaged the optical signals of 20-50 Respiratory cycles to obtain an optical image correlating specifically to inspiratory activity. 2. Four areas that were excited or inhibited corresponding to the Respiratory cycles were detected. (i) The most rostral activity was in the rostral and lateral parts of the pons, with activity mainly in the inspiratory phase, corresponding to the pontine-Respiratory group. (ii) In the midpontine level, inspiratory activity followed by long-lasting hyperpolarization appeared in the midlateral parts. This part was presumed to reflect activity in the locus coeruleus. The hyperpolarization became almost negligible after treatment with the alpha-adrenergic antagonist, phentolamine. (iii) In the dorsal medulla, the predominantly inspiratory activity was detected at the rostral level of the area postrema. This part was considered to reflect activity mainly of the hypoglossal nucleus. (iv) At a similar level, we also detected weak and disperse inspiratory activity extending more laterally and caudally than that of the hypoglossal nucleus activity. This might reflect activity of the dorsal Respiratory group. 3. In conclusion, the present optical recording study revealed that the dorsal part of the lower brainstem in the in vitro preparation is noticeably active as well as the ventral part shown in the previous study. This method is very useful for analysis of pharmacological properties, as well as the spatio-temporal pattern of Respiratory-related network activity in the brainstem.
-
developmental changes in the spatio temporal pattern of Respiratory Neuron activity in the medulla of late fetal rat
Neuroscience, 2005Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:We investigated how the spatio-temporal pattern of Respiratory Neuron network activity in the ventral medulla changes during the late fetal period of rat. Brainstem-spinal cord preparations isolated from rat fetuses on embryonic days 17-21 (E17-E21) were stained with a voltage-sensitive dye for optical image analysis of Neuronal activity of the ventral medulla. The spatio-temporal pattern of Respiratory Neuron activity in the preparation from E20 to E21 was basically identical to that of neonatal rat; pre-inspiratory activity in a limited region of the rostral ventrolateral medulla, the para-facial region, preceded by several hundred milliseconds the onset of inspiratory activity in the more caudal ventrolateral medulla, the pre-Botzinger complex level. In contrast, in E17-E18 specimens, pre-inspiratory activity could not be detected in the rostral medulla at the level of the facial nucleus. Neuronal activity appeared to begin at the pre-Botzinger complex level shortly before onset of the inspiratory burst. Strong activity then developed in the facial nucleus and peaked in the post-inspiratory phase. The transition of these patterns of Respiratory activity occurred at E19. We conclude that the changes in the spatio-temporal pattern of Neuronal activity reflect developmental changes in the cellular elements underlying rhythm generation in the fetal Respiratory Neuron network. We suggest that the pre-inspiratory Neuron network of the para-facial region in the rostral ventrolateral medulla functions as the rhythm generator after E19/20.
-
a novel functional Neuron group for Respiratory rhythm generation in the ventral medulla
The Journal of Neuroscience, 2003Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:We visualized Respiratory Neuron activity covering the entire ventral medulla using optical recordings in a newborn rat brainstem-spinal cord preparation stained with voltage-sensitive dye. We measured optical signals from several seconds before to several seconds after the inspiratory phase using the inspiratory motor nerve discharge as the trigger signal; we averaged the optical signals of 50-150 Respiratory cycles to obtain an optical image correlating particularly to inspiratory activity. The optical images we obtained from the ventral approach indicated that Neuron activity first appeared during the Respiratory cycle in the limited region of the rostral ventrolateral medulla (RVLM), preceding the onset of inspiratory activity by approximately 500 msec. During the inspiratory phase, plateau activity appeared in the more caudal ventrolateral medulla at the level of the most rostral roots of the XIIth nerve. Comparison with electrophysiological recordings from Respiratory Neurons in the RVLM suggested that the optical signals preceding the inspiratory burst reflect preinspiratory Neuron activity in this area. This RVLM area was determined to be ventrolateral to the facial nucleus and close to the ventral surface. We referred to this functional Neuron group as the para-facial Respiratory group (pFRG). Partial, bilateral electrical lesioning of the pFRG significantly reduced the Respiratory frequency, together with changes in the spatiotemporal pattern of Respiratory Neuron activity. Our findings suggest that the pFRG comprises a Neuronal population that is involved in the primary Respiratory rhythm generation in the rostrocaudally extending Respiratory Neuron network of the medulla.
-
development of the rat Respiratory Neuron network during the late fetal period
Neuroscience Research, 2002Co-Authors: Hiroshi Onimaru, Ikuo HommaAbstract:Abstract We studied developmental changes in Respiratory-like C4 activity and Respiratory-related Neurons in the ventrolateral medulla (VLM) of brainstem–spinal cord preparations from rat fetuses after embryonic day 16 (E16). In addition to Respiratory nerve activity, non-Respiratory activity was recorded from the C4 ventral root of preparations before E19. The burst duration of Respiratory nerve discharge increased markedly at E19/20. Subtypes of Neurons similar to newborn Respiratory Neurons were found in preparations with prolonged burst duration (more than 400 ms) after E20. These subtypes were not evident in preparations with short burst duration (less than 300 ms) before E19. About 60% of the inspiratory Neurons in E17–19 preparations produced voltage-dependent burst activity, which was preserved in low Ca 2+ /high Mg 2+ synaptic blockade solution. In about 11% of the inspiratory Neurons of E18–19 preparations, activation of one Neuron induced activation of the inspiratory Neuron network and generation of a full C4 inspiratory burst. The present findings suggest that Respiratory Neuron networks mature functionally to the level of the neonatal Respiratory Neuron networks during gestation period E19/20. Potentiation of synaptic interaction between Respiratory Neurons, causing developmental changes in the burst pattern, might be involved in the maturation process during late fetal stages.
Jonathan E Rubin - One of the best experts on this subject based on the ideXlab platform.
-
dynamics of ramping bursts in a Respiratory Neuron model
arXiv: Neurons and Cognition, 2021Co-Authors: Muhammad U Abdulla, Ryan S Phillips, Jonathan E RubinAbstract:Intensive computational and theoretical work has led to the development of mutliple mathematical models for bursting in Respiratory Neurons in the pre-Botzinger Complex (pre-BotC) of the mammalian brainstem. Nonetheless, these previous models have not captured the pre-inspiratory ramping aspects of these Neurons' activity patterns, in which relatively slow tonic spiking gradually progresses to faster spiking and a full blown burst, with a corresponding gradual development of an underlying plateau potential. In this work, we show that the incorporation of the dynamics of the extracellular potassium ion concentration into an existing model for pre-BotC Neuron bursting, along with some parameter updates, suffices to induce this ramping behavior. Using fast-slow decomposition, we show that this activity can be considered as a form of parabolic bursting, but with burst termination at a homoclinic bifurcation rather than as a SNIC bifurcation. We also investigate the parameter-dependence of these solutions and show that the proposed model yields a greater dynamic range of burst frequencies, durations, and duty cycles than those produced by other models in the literature.
-
complex bursting dynamics in an embryonic Respiratory Neuron model
Chaos, 2020Co-Authors: Yangyang Wang, Jonathan E RubinAbstract:Pre-Botzinger complex (pre-BotC) network activity within the mammalian brainstem controls the inspiratory phase of the Respiratory rhythm. While bursting in pre-BotC Neurons during the postnatal period has been extensively studied, less is known regarding inspiratory pacemaker Neuron behavior at embryonic stages. Recent data in mouse embryo brainstem slices have revealed the existence of a variety of bursting activity patterns depending on distinct combinations of burst-generating INaP and ICAN conductances. In this work, we consider a model of an isolated embryonic pre-BotC Neuron featuring two distinct bursting mechanisms. We use methods of dynamical systems theory, such as phase plane analysis, fast-slow decomposition, and bifurcation analysis, to uncover mechanisms underlying several different types of intrinsic bursting dynamics observed experimentally including several forms of plateau bursts, bursts involving depolarization block, and various combinations of these patterns. Our analysis also yields predictions about how changes in the balance of the two bursting mechanisms contribute to alterations in an inspiratory pacemaker Neuron activity during prenatal development.
-
multiple timescale mixed bursting dynamics in a Respiratory Neuron model
Journal of Computational Neuroscience, 2016Co-Authors: Yangyang Wang, Jonathan E RubinAbstract:Experimental results in rodent medullary slices containing the pre-Botzinger complex (pre-BotC) have identified multiple bursting mechanisms based on persistent sodium current (INaP) and intracellular Ca2+. The classic two-timescale approach to the analysis of pre-BotC bursting treats the inactivation of INaP, the calcium concentration, as well as the Ca2+-dependent inactivation of IP3 as slow variables and considers other evolving quantities as fast variables. Based on its time course, however, it appears that a novel mixed bursting (MB) solution, observed both in recordings and in model pre-BotC Neurons, involves at least three timescales. In this work, we consider a single-compartment model of a pre-BotC inspiratory Neuron that can exhibit both INaP and Ca2+ oscillations and has the ability to produce MB solutions. We use methods of dynamical systems theory, such as phase plane analysis, fast-slow decomposition, and bifurcation analysis, to better understand the mechanisms underlying the MB solution pattern. Rather surprisingly, we discover that a third timescale is not actually required to generate mixed bursting solutions. Through our analysis of timescales, we also elucidate how the pre-BotC Neuron model can be tuned to improve the robustness of the MB solution.
-
A Closed-Loop Model of the Respiratory System: Focus on Hypercapnia and Active Expiration
2016Co-Authors: Yaroslav I. Molkov, Jonathan E Rubin, Jeffrey C Smith, Natalia A. Shevtsova, Choongseok Park, Alona Ben-tal, Ilya A. RybakAbstract:Breathing is a vital process providing the exchange of gases between the lungs and atmosphere. During quiet breathing, pumping air from the lungs is mostly performed by contraction of the diaphragm during inspiration, and muscle contraction during expiration does not play a significant role in ventilation. In contrast, during intense exercise or severe hypercapnia forced or active expiration occurs in which the abdominal ‘‘expiratory’ ’ muscles become actively involved in breathing. The mechanisms of this transition remain unknown. To study these mechanisms, we developed a computational model of the closed-loop Respiratory system that describes the brainstem Respiratory network controlling the pulmonary subsystem representing lung biomechanics and gas (O2 and CO2) exchange and transport. The lung subsystem provides two types of feedback to the neural subsystem: a mechanical one from pulmonary stretch receptors and a chemical one from central chemoreceptors. The neural component of the model simulates the Respiratory network that includes several interacting Respiratory Neuron types within the Bötzinger and pre-Bötzinger complexes, as well as the retrotrapezoid nucleus/parafacial Respiratory group (RTN/pFRG) representing the central chemoreception module targeted by chemical feedback. The RTN/pFRG compartment contains an independent neural generator that is activated at an increased CO2 level and controls the abdominal motor output. The lung volume is controlled by two pumps, a major one driven by th
-
a closed loop model of the Respiratory system focus on hypercapnia and active expiration
PLOS ONE, 2014Co-Authors: Yaroslav I. Molkov, Jonathan E Rubin, Jeffrey C Smith, Natalia A. Shevtsova, Choongseok Park, Alona Bental, Ilya A. RybakAbstract:Breathing is a vital process providing the exchange of gases between the lungs and atmosphere. During quiet breathing, pumping air from the lungs is mostly performed by contraction of the diaphragm during inspiration, and muscle contraction during expiration does not play a significant role in ventilation. In contrast, during intense exercise or severe hypercapnia forced or active expiration occurs in which the abdominal “expiratory” muscles become actively involved in breathing. The mechanisms of this transition remain unknown. To study these mechanisms, we developed a computational model of the closed-loop Respiratory system that describes the brainstem Respiratory network controlling the pulmonary subsystem representing lung biomechanics and gas (O2 and CO2) exchange and transport. The lung subsystem provides two types of feedback to the neural subsystem: a mechanical one from pulmonary stretch receptors and a chemical one from central chemoreceptors. The neural component of the model simulates the Respiratory network that includes several interacting Respiratory Neuron types within the Botzinger and pre-Botzinger complexes, as well as the retrotrapezoid nucleus/parafacial Respiratory group (RTN/pFRG) representing the central chemoreception module targeted by chemical feedback. The RTN/pFRG compartment contains an independent neural generator that is activated at an increased CO2 level and controls the abdominal motor output. The lung volume is controlled by two pumps, a major one driven by the diaphragm and an additional one activated by abdominal muscles and involved in active expiration. The model represents the first attempt to model the transition from quiet breathing to breathing with active expiration. The model suggests that the closed-loop Respiratory control system switches to active expiration via a quantal acceleration of expiratory activity, when increases in breathing rate and phrenic amplitude no longer provide sufficient ventilation. The model can be used for simulation of closed-loop control of breathing under different conditions including Respiratory disorders.
Yoshitaka Oku - One of the best experts on this subject based on the ideXlab platform.
-
anatomical architecture and responses to acidosis of a novel Respiratory Neuron group in the high cervical spinal cord hcrg of the neonatal rat
Advances in Experimental Medicine and Biology, 2009Co-Authors: Yasumasa Okada, Shigefumi Yokota, Yoshio Shinozaki, Ryoma Aoyama, Yukihiko Yasui, Makio Ishiguro, Yoshitaka OkuAbstract:It has been postulated that there exists a Neuronal mechanism that generates Respiratory rhythm and modulates Respiratory output pattern in the high cervical spinal cord. Recently, we have found a novel Respiratory Neuron group in the ventral portion of the high cervical spinal cord, and named it the high cervical spinal cord Respiratory group (HCRG). In the present study, we analyzed the detailed anatomical architecture of the HCRG region by double immunostaining of the region using a Neuron-specific marker (NeuN) and a marker for motoNeurons (ChAT) in the neonatal rat. We found a large number of small NeuN-positive cells without ChAT-immunoreactivity, which were considered interNeurons. We also found two and three clusters of motoNeurons in the ventral portion of the ventral horn at C1 and C2 levels, respectively. Next, we examined responses of HCRG Neurons to Respiratory and metabolic acidosis in vitro by voltage-imaging together with cross correlation techniques, i.e., by correlation coefficient imaging, in order to understand the functional role of HCRG Neurons. Both Respiratory and metabolic acidosis caused the same pattern of changes in their spatiotemporal activation profiles, and the Respiratory-related area was enlarged in the HCRG region. After acidosis was introduced, preinspiratory phase-dominant activity was recruited in a number of pixels, and more remarkably inspiratory phase-dominant activity was recruited in a large number of pixels. We suggest that the HCRG composes a local Respiratory Neuronal network consisting of interNeurons and motoNeurons and plays an important role in Respiratory augmentation in response to acidosis.
-
Respiratory Neuron group in the high cervical spinal cord discovered by optical imaging
Neuroreport, 2008Co-Authors: Yoshitaka Oku, Akihito Okabe, Tetsu Hayakawa, Yasumasa OkadaAbstract:Spontaneous breathing occurs transiently in spinalized animals suggesting that the cervical spinal cord generates Respiratory rhythm. We recorded optical signals from isolated brainstem-spinal cord preparations of neonatal rats using a voltage-sensitive dye, and visualized Respiratory-related activity by processing the optical data with a correlation coefficient imaging technique. We identified a novel region that extended from the medullo-spinal junction to the C2 segment, approximately 100-300 mum deep from the ventral surface, and termed the high cervical Respiratory group. We recorded inspiratory and preinspiratory-inspiratory Neurons in this region. High cervical Respiratory group Neurons are distinct from motoNeurons, because they are small, spindle in shape, and have only two or three long processes, and thus may be interNeurons that are involved in Respiratory rhythmogenesis in the cervical spinal cord.
Yasumasa Okada - One of the best experts on this subject based on the ideXlab platform.
-
anatomical architecture and responses to acidosis of a novel Respiratory Neuron group in the high cervical spinal cord hcrg of the neonatal rat
Advances in Experimental Medicine and Biology, 2009Co-Authors: Yasumasa Okada, Shigefumi Yokota, Yoshio Shinozaki, Ryoma Aoyama, Yukihiko Yasui, Makio Ishiguro, Yoshitaka OkuAbstract:It has been postulated that there exists a Neuronal mechanism that generates Respiratory rhythm and modulates Respiratory output pattern in the high cervical spinal cord. Recently, we have found a novel Respiratory Neuron group in the ventral portion of the high cervical spinal cord, and named it the high cervical spinal cord Respiratory group (HCRG). In the present study, we analyzed the detailed anatomical architecture of the HCRG region by double immunostaining of the region using a Neuron-specific marker (NeuN) and a marker for motoNeurons (ChAT) in the neonatal rat. We found a large number of small NeuN-positive cells without ChAT-immunoreactivity, which were considered interNeurons. We also found two and three clusters of motoNeurons in the ventral portion of the ventral horn at C1 and C2 levels, respectively. Next, we examined responses of HCRG Neurons to Respiratory and metabolic acidosis in vitro by voltage-imaging together with cross correlation techniques, i.e., by correlation coefficient imaging, in order to understand the functional role of HCRG Neurons. Both Respiratory and metabolic acidosis caused the same pattern of changes in their spatiotemporal activation profiles, and the Respiratory-related area was enlarged in the HCRG region. After acidosis was introduced, preinspiratory phase-dominant activity was recruited in a number of pixels, and more remarkably inspiratory phase-dominant activity was recruited in a large number of pixels. We suggest that the HCRG composes a local Respiratory Neuronal network consisting of interNeurons and motoNeurons and plays an important role in Respiratory augmentation in response to acidosis.
-
Respiratory Neuron group in the high cervical spinal cord discovered by optical imaging
Neuroreport, 2008Co-Authors: Yoshitaka Oku, Akihito Okabe, Tetsu Hayakawa, Yasumasa OkadaAbstract:Spontaneous breathing occurs transiently in spinalized animals suggesting that the cervical spinal cord generates Respiratory rhythm. We recorded optical signals from isolated brainstem-spinal cord preparations of neonatal rats using a voltage-sensitive dye, and visualized Respiratory-related activity by processing the optical data with a correlation coefficient imaging technique. We identified a novel region that extended from the medullo-spinal junction to the C2 segment, approximately 100-300 mum deep from the ventral surface, and termed the high cervical Respiratory group. We recorded inspiratory and preinspiratory-inspiratory Neurons in this region. High cervical Respiratory group Neurons are distinct from motoNeurons, because they are small, spindle in shape, and have only two or three long processes, and thus may be interNeurons that are involved in Respiratory rhythmogenesis in the cervical spinal cord.