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Palkovic B, Mustapic S, Saric I, Stuth EAE, Stucke AG, Zuperku EJ. Changes in pontine and preBötzinger/Bötzinger complex neuronal activity during remifentanil-induced respiratory depression in decerebrate dogs. Front Physiol 2023; 14:1156076. [PMID: 37362432 PMCID: PMC10285059 DOI: 10.3389/fphys.2023.1156076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Introduction: In vivo studies using selective, localized opioid antagonist injections or localized opioid receptor deletion have identified that systemic opioids dose-dependently depress respiratory output through effects in multiple respiratory-related brainstem areas. Methods: With approval of the subcommittee on animal studies of the Zablocki VA Medical Center, experiments were performed in 53 decerebrate, vagotomized, mechanically ventilated dogs of either sex during isocapnic hyperoxia. We performed single neuron recordings in the Pontine Respiratory Group (PRG, n = 432) and preBötzinger/Bötzinger complex region (preBötC/BötC, n = 213) before and during intravenous remifentanil infusion (0.1-1 mcg/kg/min) and then until complete recovery of phrenic nerve activity. A generalized linear mixed model was used to determine changes in Fn with remifentanil and the statistical association between remifentanil-induced changes in Fn and changes in inspiratory and expiratory duration and peak phrenic activity. Analysis was controlled via random effects for animal, run, and neuron type. Results: Remifentanil decreased Fn in most neuron subtypes in the preBötC/BötC as well as in inspiratory (I), inspiratory-expiratory, expiratory (E) decrementing and non-respiratory modulated neurons in the PRG. The decrease in PRG inspiratory and non-respiratory modulated neuronal activity was associated with an increase in inspiratory duration. In the preBötC, the decrease in I-decrementing neuron activity was associated with an increase in expiratory and of E-decrementing activity with an increase in inspiratory duration. In contrast, decreased activity of I-augmenting neurons was associated with a decrease in inspiratory duration. Discussion: While statistical associations do not necessarily imply a causal relationship, our data suggest mechanisms for the opioid-induced increase in expiratory duration in the PRG and preBötC/BötC and how inspiratory failure at high opioid doses may result from a decrease in activity and decrease in slope of the pre-inspiratory ramp-like activity in preBötC/BötC pre-inspiratory neurons combined with a depression of preBötC/BötC I-augmenting neurons. Additional studies must clarify whether the observed changes in neuronal activity are due to direct neuronal inhibition or decreased excitatory inputs.
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Affiliation(s)
- Barbara Palkovic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Sanda Mustapic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- University Hospital Dubrava, Zagreb, Croatia
| | - Ivana Saric
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- University Hospital Split, Split, Croatia
| | - Eckehard A. E. Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Children’s Wisconsin, Milwaukee, WI, United States
| | - Astrid G. Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Children’s Wisconsin, Milwaukee, WI, United States
| | - Edward J. Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Clement J Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States
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Dose-dependent Respiratory Depression by Remifentanil in the Rabbit Parabrachial Nucleus/Kölliker-Fuse Complex and Pre-Bötzinger Complex. Anesthesiology 2021; 135:649-672. [PMID: 34352068 DOI: 10.1097/aln.0000000000003886] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Recent studies showed partial reversal of opioid-induced respiratory depression in the pre-Bötzinger complex and the parabrachial nucleus/Kölliker-Fuse complex. The hypothesis for this study was that opioid antagonism in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex completely reverses respiratory depression from clinically relevant opioid concentrations. METHODS Experiments were performed in 48 adult, artificially ventilated, decerebrate rabbits. The authors decreased baseline respiratory rate ~50% with intravenous, "analgesic" remifentanil infusion or produced apnea with remifentanil boluses and investigated the reversal with naloxone microinjections (1 mM, 700 nl) into the Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex. In another group of animals, naloxone was injected only into the pre-Bötzinger complex to determine whether prior parabrachial nucleus/Kölliker-Fuse complex injection impacted the naloxone effect. Last, the µ-opioid receptor agonist [d-Ala,2N-MePhe,4Gly-ol]-enkephalin (100 μM, 700 nl) was injected into the parabrachial nucleus/Kölliker-Fuse complex. The data are presented as medians (25 to 75%). RESULTS Remifentanil infusion reduced the respiratory rate from 36 (31 to 40) to 16 (15 to 21) breaths/min. Naloxone microinjections into the bilateral Kölliker-Fuse nucleus, parabrachial nucleus, and pre-Bötzinger complex increased the rate to 17 (16 to 22, n = 19, P = 0.005), 23 (19 to 29, n = 19, P < 0.001), and 25 (22 to 28) breaths/min (n = 11, P < 0.001), respectively. Naloxone injection into the parabrachial nucleus/Kölliker-Fuse complex prevented apnea in 12 of 17 animals, increasing the respiratory rate to 10 (0 to 12) breaths/min (P < 0.001); subsequent pre-Bötzinger complex injection prevented apnea in all animals (13 [10 to 19] breaths/min, n = 12, P = 0.002). Naloxone injection into the pre-Bötzinger complex alone increased the respiratory rate to 21 (15 to 26) breaths/min during analgesic concentrations (n = 10, P = 0.008) but not during apnea (0 [0 to 0] breaths/min, n = 9, P = 0.500). [d-Ala,2N-MePhe,4Gly-ol]-enkephalin injection into the parabrachial nucleus/Kölliker-Fuse complex decreased respiratory rate to 3 (2 to 6) breaths/min. CONCLUSIONS Opioid reversal in the parabrachial nucleus/Kölliker-Fuse complex plus pre-Bötzinger complex only partially reversed respiratory depression from analgesic and even less from "apneic" opioid doses. The lack of recovery pointed to opioid-induced depression of respiratory drive that determines the activity of these areas. EDITOR’S PERSPECTIVE
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Interaction between the pulmonary stretch receptor and pontine control of expiratory duration. Respir Physiol Neurobiol 2021; 293:103715. [PMID: 34126261 DOI: 10.1016/j.resp.2021.103715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/19/2021] [Accepted: 06/08/2021] [Indexed: 11/20/2022]
Abstract
Medial parabrachial nucleus (mPBN) neuronal activity plays a key role in controlling expiratory (E)-duration (TE). Pulmonary stretch receptor (PSR) activity during the E-phase prolongs TE. The aims of this study were to characterize the interaction between the PSR and mPBN control of TE and underlying mechanisms. Decerebrated mechanically ventilated dogs were studied. The mPBN subregion was activated by electrical stimulation via bipolar microelectrode. PSR afferents were activated by low-level currents applied to the transected central vagus nerve. Both stimulus-frequency patterns during the E-phase were synchronized to the phrenic neurogram; TE was measured. A functional mathematical model for the control of TE and extracellular recordings from neurons in the preBötzinger/Bötzinger complex (preBC/BC) were used to understand mechanisms. Findings show that the mPBN gain-modulates, via attenuation, the PSR-mediated reflex. The model suggested functional sites for attenuation and neuronal data suggested correlates. The PSR- and PB-inputs appear to interact on E-decrementing neurons, which synaptically inhibit pre-I neurons, delaying the onset of the next I-phase.
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Cinelli E, Bongianni F, Pantaleo T, Mutolo D. Activation of μ-opioid receptors differentially affects the preBötzinger Complex and neighbouring regions of the respiratory network in the adult rabbit. Respir Physiol Neurobiol 2020; 280:103482. [DOI: 10.1016/j.resp.2020.103482] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/05/2020] [Accepted: 06/12/2020] [Indexed: 11/25/2022]
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Zuperku EJ, Stucke AG, Tomlinson J, Krolikowski JG, Hopp FA, Stuth EA. Neuronal Correlates Mediating the Pontine Modulation of the Hering‐Breuer Expiratory Facilitatory (HBEF) Reflex. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.548.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Edward J Zuperku
- Research ServiceZablocki VA Medical CenterMilwaukeeWI
- AnesthesiologyMedical College of WisconsinWauwatosaWI
| | - Astrid G. Stucke
- Research ServiceZablocki VA Medical CenterMilwaukeeWI
- AnesthesiologyMedical College of WisconsinWauwatosaWI
- Pediatric AnesthesiaChildrens Hospital of WisconsinMilwaukeeWI
| | | | | | | | - Eckehard A. Stuth
- Research ServiceZablocki VA Medical CenterMilwaukeeWI
- AnesthesiologyMedical College of WisconsinWauwatosaWI
- Pediatric AnesthesiaChildrens Hospital of WisconsinMilwaukeeWI
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An arterially perfused brainstem preparation of guinea pig to study central mechanisms of airway defense. J Neurosci Methods 2019; 317:49-60. [DOI: 10.1016/j.jneumeth.2019.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/07/2019] [Accepted: 02/07/2019] [Indexed: 11/18/2022]
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Cook-Snyder DR, Miller JR, Navarrete-Opazo AA, Callison JJ, Peterson RC, Hopp FA, Stuth EAE, Zuperku EJ, Stucke AG. The contribution of endogenous glutamatergic input in the ventral respiratory column to respiratory rhythm. Respir Physiol Neurobiol 2019; 260:37-52. [PMID: 30502519 PMCID: PMC6397772 DOI: 10.1016/j.resp.2018.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/22/2018] [Accepted: 11/25/2018] [Indexed: 12/28/2022]
Abstract
Glutamate is the predominant excitatory neurotransmitter in the ventral respiratory column; however, the contribution of glutamatergic excitation in the individual subregions to respiratory rhythm generation has not been fully delineated. In an adult, in vivo, decerebrate rabbit model during conditions of mild hyperoxic hypercapnia we blocked glutamatergic excitation using the receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and d(-)-2-amino-5-phosphonopentanoic acid (AP5). Disfacilitation of the preBötzinger Complex caused a decrease in inspiratory and expiratory duration as well as peak phrenic amplitude and ultimately apnea. Disfacilitation of the Bötzinger Complex caused a decrease in inspiratory and expiratory duration; subsequent disfacilitation of the preBötzinger Complex resulted in complete loss of the respiratory pattern but maintained tonic inspiratory activity. We conclude that glutamatergic drive to the preBötzinger Complex is essential for respiratory rhythm generation. Glutamatergic drive to the Bötzinger Complex significantly affects inspiratory and expiratory phase duration. Bötzinger Complex neurons are responsible for maintaining the silent expiratory phase of the phrenic neurogram.
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Affiliation(s)
| | - Justin R Miller
- Department of Biology, Carthage College, Kenosha, WI, United States
| | | | - Jennifer J Callison
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Robin C Peterson
- Department of Neuroscience, Carthage College, Kenosha, WI, United States
| | - Francis A Hopp
- Zablocki VA Medical Center, Milwaukee, WI, United States
| | - Eckehard A E Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Milwaukee, WI, United States
| | - Edward J Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Zablocki VA Medical Center, Milwaukee, WI, United States
| | - Astrid G Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Milwaukee, WI, United States.
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Iovino L, Mutolo D, Cinelli E, Contini M, Pantaleo T, Bongianni F. Breathing stimulation mediated by 5-HT1A and 5-HT3 receptors within the preBötzinger complex of the adult rabbit. Brain Res 2019; 1704:26-39. [DOI: 10.1016/j.brainres.2018.09.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/10/2018] [Accepted: 09/18/2018] [Indexed: 02/06/2023]
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Zuperku EJ, Stucke AG, Krolikowski JG, Tomlinson J, Hopp FA, Stuth EA. Inputs to medullary respiratory neurons from a pontine subregion that controls breathing frequency. Respir Physiol Neurobiol 2018; 265:127-140. [PMID: 29964165 DOI: 10.1016/j.resp.2018.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/10/2018] [Accepted: 06/04/2018] [Indexed: 11/30/2022]
Abstract
Neurons in a subregion of the medial parabrachial (PB) complex control expiratory duration (TE) and the inspiratory on-switch. To better understanding the underlying mechanisms, this study aimed to determine the types of medullary neurons in the rhythmogenic preBötzinger/Bötzinger Complex (preBötC/BötC) and adjacent areas that receive synaptic inputs from the PB subregion and whether these inputs are excitatory or inhibitory in nature. Highly localized electrical stimuli in the PB subregion combined with multi-electrode recordings from respiratory neurons and phrenic nerve activities were used to generate stimulus-to-spike event histograms to detect correlations in decerebrate, vagotomized dogs during isocapnic hyperoxia. Short-time scale correlations were found in 237/442 or ∼54% of the ventral respiratory column (VRC) neurons. Inhibition of E-neurons was ∼2.5X greater than for I-neurons, while Pre-I and I-neurons were excited. These findings indicate that the control of TE and the inspiratory on-switch by the PB subregion are mediated by a marked inhibition of BötC E-neurons combined with an excitation of I-neurons, especially pre-I neurons.
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Affiliation(s)
- Edward J Zuperku
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.
| | - Astrid G Stucke
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, WI, United States
| | - John G Krolikowski
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jack Tomlinson
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Francis A Hopp
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States
| | - Eckehard A Stuth
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI, United States; Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, WI, United States
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Baertsch NA, Baertsch HC, Ramirez JM. The interdependence of excitation and inhibition for the control of dynamic breathing rhythms. Nat Commun 2018; 9:843. [PMID: 29483589 PMCID: PMC5827754 DOI: 10.1038/s41467-018-03223-x] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 01/26/2018] [Indexed: 11/09/2022] Open
Abstract
The preBötzinger Complex (preBötC), a medullary network critical for breathing, relies on excitatory interneurons to generate the inspiratory rhythm. Yet, half of preBötC neurons are inhibitory, and the role of inhibition in rhythmogenesis remains controversial. Using optogenetics and electrophysiology in vitro and in vivo, we demonstrate that the intrinsic excitability of excitatory neurons is reduced following large depolarizing inspiratory bursts. This refractory period limits the preBötC to very slow breathing frequencies. Inhibition integrated within the network is required to prevent overexcitation of preBötC neurons, thereby regulating the refractory period and allowing rapid breathing. In vivo, sensory feedback inhibition also regulates the refractory period, and in slowly breathing mice with sensory feedback removed, activity of inhibitory, but not excitatory, neurons restores breathing to physiological frequencies. We conclude that excitation and inhibition are interdependent for the breathing rhythm, because inhibition permits physiological preBötC bursting by controlling refractory properties of excitatory neurons.
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Affiliation(s)
- Nathan Andrew Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Avenue JMB10, Seattle, WA, 98101, USA
| | - Hans Christopher Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Avenue JMB10, Seattle, WA, 98101, USA
| | - Jan Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Avenue JMB10, Seattle, WA, 98101, USA.
- Department of Neurological Surgery, University of Washington, 1900 9th Avenue, JMB10, Seattle, WA, 98101, USA.
- Department of Pediatrics, University of Washington, 1900 9th Avenue, JMB10, Seattle, WA, 98101, USA.
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Langer TM, Neumueller SE, Crumley E, Burgraff NJ, Talwar S, Hodges MR, Pan L, Forster HV. Ventilation and neurochemical changes during µ-opioid receptor activation or blockade of excitatory receptors in the hypoglossal motor nucleus of goats. J Appl Physiol (1985) 2017; 123:1532-1544. [PMID: 28839004 DOI: 10.1152/japplphysiol.00592.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Neuromodulator interdependence posits that changes in one or more neuromodulators are compensated by changes in other modulators to maintain stability in the respiratory control network. Herein, we studied compensatory neuromodulation in the hypoglossal motor nucleus (HMN) after chronic implantation of microtubules unilaterally ( n = 5) or bilaterally ( n = 5) into the HMN. After recovery, receptor agonists or antagonists in mock cerebrospinal fluid (mCSF) were dialyzed during the awake and non-rapid eye movement (NREM) sleep states. During day studies, dialysis of the µ-opioid inhibitory receptor agonist [d-Ala2, N-MePhe4, Gly-ol]enkephalin (DAMGO; 100 µM) decreased pulmonary ventilation (V̇i), breathing frequency ( f), and genioglossus (GG) muscle activity but did not alter neuromodulators measured in the effluent mCSF. However, neither unilateral dialysis of a broad spectrum muscarinic receptor antagonist (atropine; 50 mM) nor unilateral or bilateral dialysis of a mixture of excitatory receptor antagonists altered V̇i or GG activity, but all of these did increase HMN serotonin (5-HT) levels. Finally, during night studies, DAMGO and excitatory receptor antagonist decreased ventilatory variables during NREM sleep but not during wakefulness. These findings contrast with previous dialysis studies in the ventral respiratory column (VRC) where unilateral DAMGO or atropine dialysis had no effects on breathing and bilateral DAMGO or unilateral atropine increased V̇i and f and decreased GABA or increased 5-HT, respectively. Thus we conclude that the mechanisms of compensatory neuromodulation are less robust in the HMN than in the VRC under physiological conditions in adult goats, possibly because of site differences in the underlying mechanisms governing neuromodulator release and consequently neuronal activity, and/or responsiveness of receptors to compensatory neuromodulators. NEW & NOTEWORTHY Activation of inhibitory µ-opioid receptors in the hypoglossal motor nucleus decreased ventilation under physiological conditions and did not affect neurochemicals in effluent dialyzed mock cerebral spinal fluid. These findings contrast with studies in the ventral respiratory column where unilateral [d-Ala2, N-MePhe4, Gly-ol]enkephalin (DAMGO) had no effects on ventilation and bilateral DAMGO or unilateral atropine increased ventilation and decreased GABA or increased serotonin, respectively. Our data support the hypothesis that mechanisms that govern local compensatory neuromodulation within the brain stem are site specific under physiological conditions.
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Affiliation(s)
- Thomas M Langer
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | | | - Emma Crumley
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Nicholas J Burgraff
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Sawan Talwar
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin.,Neuroscience Research Center, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Lawrence Pan
- Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
| | - Hubert V Forster
- Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin.,Neuroscience Research Center, Medical College of Wisconsin , Milwaukee, Wisconsin.,Zablocki Veterans Affairs Medical Center , Milwaukee, Wisconsin
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Ghali MGZ, Marchenko V. Effects of vagotomy on hypoglossal and phrenic responses to hypercapnia in the decerebrate rat. Respir Physiol Neurobiol 2016; 232:13-21. [DOI: 10.1016/j.resp.2016.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/15/2016] [Accepted: 05/15/2016] [Indexed: 11/15/2022]
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Opioid-induced Respiratory Depression Is Only Partially Mediated by the preBötzinger Complex in Young and Adult Rabbits In Vivo. Anesthesiology 2015; 122:1288-98. [PMID: 25751234 DOI: 10.1097/aln.0000000000000628] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The preBötzinger Complex (preBC) plays an important role in respiratory rhythm generation. This study was designed to determine whether the preBC mediated opioid-induced respiratory rate depression at clinically relevant opioid concentrations in vivo and whether this role was age dependent. METHODS Studies were performed in 22 young and 32 adult New Zealand White rabbits. Animals were anesthetized, mechanically ventilated, and decerebrated. The preBC was identified by the tachypneic response to injection of D,L-homocysteic acid. (1) The μ-opioid receptor agonist [D-Ala2,N-Me-Phe4,Gly-ol]-enkephalin (DAMGO, 100 μM) was microinjected into the bilateral preBC and reversed with naloxone (1 mM) injection into the preBC. (2) Respiratory depression was achieved with intravenous remifentanil (0.08 to 0.5 μg kg(-1) min(-1)). Naloxone (1 mM) was microinjected into the preBC in an attempt to reverse the respiratory depression. RESULTS (1) DAMGO injection depressed respiratory rate by 6 ± 8 breaths/min in young and adult rabbits (mean ± SD, P < 0.001). DAMGO shortened the inspiratory and lengthened the expiratory fraction of the respiratory cycle by 0.24 ± 0.2 in adult and young animals (P < 0.001). (2) During intravenous remifentanil infusion, local injection of naloxone into the preBC partially reversed the decrease in inspiratory fraction/increase in expiratory fraction in young and adult animals (0.14 ± 0.14, P < 0.001), but not the depression of respiratory rate (P = 0.19). PreBC injections did not affect respiratory drive. In adult rabbits, the contribution of non-preBC inputs to expiratory phase duration was larger than preBC inputs (3.5 [-5.2 to 1.1], median [25 to 75%], P = 0.04). CONCLUSIONS Systemic opioid effects on respiratory phase timing can be partially reversed in the preBC without reversing the depression of respiratory rate.
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Radocaj T, Mustapic S, Prkic I, Stucke AG, Hopp FA, Stuth EAE, Zuperku EJ. Activation of 5-HT1A receptors in the preBötzinger region has little impact on the respiratory pattern. Respir Physiol Neurobiol 2015; 212-214:9-19. [PMID: 25850079 DOI: 10.1016/j.resp.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/10/2015] [Accepted: 03/19/2015] [Indexed: 11/24/2022]
Abstract
The preBötzinger (preBötC) complex has been suggested as the primary site where systemically administered selective serotonin agonists have been shown to reduce or prevent opioid-induced depression of breathing. However, this hypothesis has not been tested pharmacologically in vivo. This study sought to determine whether 5-HT1A receptors within the preBötC and ventral respiratory column (VRC) mediate the tachypneic response induced by intravenous (IV) (±)-8-Hydroxy-2-diproplyaminotetralin hydrobromide (8-OH-DPAT) in a decerebrated dog model. IV 8-OH-DPAT (19 ± 2 μg/kg) reduced both inspiratory (I) and expiratory (E) durations by ∼ 40%, but had no effect on peak phrenic activity (PPA). Picoejection of 1, 10, and 100 μM 8-OH-DPAT on I and E preBötC neurons produced dose-dependent decreases up to ∼ 40% in peak discharge. Surprisingly, microinjections of 8-OH-DPAT and 5-HT within the VRC from the obex to 9 mm rostral had no effect on timing and PPA. These results suggest that the tachypneic effects of IV 8-OH-DPAT are due to receptors located outside of the areas we studied.
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Affiliation(s)
- Tomislav Radocaj
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Sanda Mustapic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Ivana Prkic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Astrid G Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, United States
| | - Francis A Hopp
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Eckehard A E Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, United States
| | - Edward J Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States.
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Lalley PM, Pilowsky PM, Forster HV, Zuperku EJ. Rebuttal from Peter M. Lalley, Paul M. Pilowsky, Hubert V. Forster and Edward J. Zuperku. J Physiol 2015; 592:1169. [PMID: 24634014 DOI: 10.1113/jphysiol.2013.268318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Lalley PM, Pilowsky PM, Forster HV, Zuperku EJ. CrossTalk opposing view: The pre-Botzinger complex is not essential for respiratory depression following systemic administration of opioid analgesics. J Physiol 2015; 592:1163-6. [PMID: 24634012 DOI: 10.1113/jphysiol.2013.258830] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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17
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Abstract
Pontine respiratory nuclei provide synaptic input to medullary rhythmogenic circuits to shape and adapt the breathing pattern. An understanding of this statement depends on appreciating breathing as a behavior, rather than a stereotypic rhythm. In this review, we focus on the pontine-mediated inspiratory off-switch (IOS) associated with postinspiratory glottal constriction. Further, IOS is examined in the context of pontine regulation of glottal resistance in response to multimodal sensory inputs and higher commands, which in turn rules timing, duration, and patterning of respiratory airflow. In addition, network plasticity in respiratory control emerges during the development of the pons. Synaptic plasticity is required for dynamic and efficient modulation of the expiratory breathing pattern to cope with rapid changes from eupneic to adaptive breathing linked to exploratory (foraging and sniffing) and expulsive (vocalizing, coughing, sneezing, and retching) behaviors, as well as conveyance of basic emotions. The speed and complexity of changes in the breathing pattern of behaving animals implies that "learning to breathe" is necessary to adjust to changing internal and external states to maintain homeostasis and survival.
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Affiliation(s)
- Mathias Dutschmann
- Florey Neurosciences Institutes, University of Melbourne, Victoria, Australia.
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18
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The rhythmic, transverse medullary slice preparation in respiratory neurobiology: contributions and caveats. Respir Physiol Neurobiol 2013; 186:236-53. [PMID: 23357617 DOI: 10.1016/j.resp.2013.01.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 01/18/2013] [Accepted: 01/21/2013] [Indexed: 11/23/2022]
Abstract
Our understanding of the sites and mechanisms underlying rhythmic breathing as well as the neuromodulatory control of respiratory rhythm, pattern, and respiratory motoneuron excitability during perinatal development has advanced significantly over the last 20 years. A major catalyst was the development in 1991 of the rhythmically-active medullary slice preparation, which provided precise mechanical and chemical control over the network as well as enhanced physical and optical access to key brainstem regions. Insights obtained in vitro have informed multiple mechanistic hypotheses. In vivo tests of these hypotheses, performed under conditions of reduced control and precision but more obvious physiological relevance, have clearly established the significance for respiratory neurobiology of the rhythmic slice preparation. We review the contributions of this preparation to current understanding/concepts in respiratory control, and outline the limitations of this approach in the context of studying rhythm and pattern generation, homeostatic control mechanisms and murine models of human genetic disorders that feature prominent breathing disturbances.
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Lindsey BG, Rybak IA, Smith JC. Computational models and emergent properties of respiratory neural networks. Compr Physiol 2012; 2:1619-70. [PMID: 23687564 PMCID: PMC3656479 DOI: 10.1002/cphy.c110016] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Computational models of the neural control system for breathing in mammals provide a theoretical and computational framework bringing together experimental data obtained from different animal preparations under various experimental conditions. Many of these models were developed in parallel and iteratively with experimental studies and provided predictions guiding new experiments. This data-driven modeling approach has advanced our understanding of respiratory network architecture and neural mechanisms underlying generation of the respiratory rhythm and pattern, including their functional reorganization under different physiological conditions. Models reviewed here vary in neurobiological details and computational complexity and span multiple spatiotemporal scales of respiratory control mechanisms. Recent models describe interacting populations of respiratory neurons spatially distributed within the Bötzinger and pre-Bötzinger complexes and rostral ventrolateral medulla that contain core circuits of the respiratory central pattern generator (CPG). Network interactions within these circuits along with intrinsic rhythmogenic properties of neurons form a hierarchy of multiple rhythm generation mechanisms. The functional expression of these mechanisms is controlled by input drives from other brainstem components,including the retrotrapezoid nucleus and pons, which regulate the dynamic behavior of the core circuitry. The emerging view is that the brainstem respiratory network has rhythmogenic capabilities at multiple levels of circuit organization. This allows flexible, state-dependent expression of different neural pattern-generation mechanisms under various physiological conditions,enabling a wide repertoire of respiratory behaviors. Some models consider control of the respiratory CPG by pulmonary feedback and network reconfiguration during defensive behaviors such as cough. Future directions in modeling of the respiratory CPG are considered.
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Affiliation(s)
- Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology and Neuroscience Program, University of South Florida College of Medicine, Tampa, Florida, USA.
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Baekey DM, Molkov YI, Paton JFR, Rybak IA, Dick TE. Effect of baroreceptor stimulation on the respiratory pattern: insights into respiratory-sympathetic interactions. Respir Physiol Neurobiol 2010; 174:135-45. [PMID: 20837166 DOI: 10.1016/j.resp.2010.09.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/26/2010] [Accepted: 09/07/2010] [Indexed: 11/17/2022]
Abstract
Sympathetic nerve activity (SNA) is modulated by respiratory activity which indicates the existence of direct interactions between the respiratory and sympathetic networks within the brainstem. Our experimental studies reveal that T(E) prolongation evoked by baroreceptor stimulation varies with respiratory phase and depends on the pons. We speculate that the sympathetic baroreceptor reflex, providing negative feedback from baroreceptors to the rostral ventrolateral medulla and SNA, has two pathways: one direct and independent of the respiratory-sympathetic interactions and the other operating via the respiratory pattern generator and is hence dependent on the respiratory modulation of SNA. Our experimental studies in the perfused in situ rat preparation and complementary computational modelling studies support the hypothesis that baroreceptor activation during expiration prolongs the T(E) via transient activation of post-inspiratory and inhibition of augmenting expiratory neurones of the Bötzinger Complex (BötC). We propose that these BötC neurones are also involved in the respiratory modulation of SNA, and contribute to the respiratory modulation of the sympathetic baroreceptor reflex.
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Affiliation(s)
- David M Baekey
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH 44106-5067, USA.
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21
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Mustapic S, Radocaj T, Sanchez A, Dogas Z, Stucke AG, Hopp FA, Stuth EAE, Zuperku EJ. Clinically relevant infusion rates of mu-opioid agonist remifentanil cause bradypnea in decerebrate dogs but not via direct effects in the pre-Bötzinger complex region. J Neurophysiol 2009; 103:409-18. [PMID: 19906886 DOI: 10.1152/jn.00188.2009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Systemic administration of mu-opioids at clinical doses for analgesia typically slows respiratory rate. Mu-opioid receptors (MORs) on pre-Bötzinger Complex (pre-BötC) respiratory neurons, the putative kernel of respiratory rhythmogenesis, are potential targets. The purpose of this study was to determine the contribution of pre-BötC MORs to the bradypnea produced in vivo by intravenous administration of clinically relevant infusion rates of remifentanil (remi), a short-acting, potent mu-opioid analgesic. In decerebrate dogs, multibarrel micropipettes were used to record pre-BötC neuronal activity and to eject the opioid antagonist naloxone (NAL, 0.5 mM), the glutamate agonist D-homocysteic acid (DLH, 20 mM), or the MOR agonist [D-Ala(2), N-Me-Phe(4), gly-ol(5)]-enkephalin (DAMGO, 100 microM). Inspiratory and expiratory durations (T(I) and T(E)) and peak phrenic nerve activity (PPA) were measured from the phrenic neurogram. The pre-BötC was functionally identified by its rate altering response (typically tachypnea) to DLH microinjection. During intravenous remi-induced bradypnea (approximately 60% decrease in central breathing frequency, f(B)), bilateral injections of NAL in the pre-BötC did not change T(I), T(E), f(B), and PPA. Also, NAL picoejected onto single pre-BötC neurons depressed by intravenous remi had no effect on their discharge. In contrast, approximately 60 microg/kg of intravenous NAL rapidly reversed all remi-induced effects. In a separate group of dogs, microinjections of DAMGO in the pre-BötC increased f(B) by 44%, while subsequent intravenous remi infusion more than offset this DAMGO induced tachypnea. These results indicate that mu-opioids at plasma concentrations that cause profound analgesia produce their bradypneic effect via MORs located outside the pre-BötC region.
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Affiliation(s)
- Sanda Mustapic
- Department of Anesthesiology, Medical College of Wisconsin, Clement J. Zablocki VA Medical Center, 5000 W. National Ave., Milwaukee, WI 53295, USA
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22
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Mörschel M, Dutschmann M. Pontine respiratory activity involved in inspiratory/expiratory phase transition. Philos Trans R Soc Lond B Biol Sci 2009; 364:2517-26. [PMID: 19651653 DOI: 10.1098/rstb.2009.0074] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Control of the timing of the inspiratory/expiratory (IE) phase transition is a hallmark of respiratory pattern formation. In principle, sensory feedback from pulmonary stretch receptors (Breuer-Hering reflex, BHR) is seen as the major controller for the IE phase transition, while pontine-based control of IE phase transition by both the pontine Kölliker-Fuse nucleus (KF) and parabrachial complex is seen as a secondary or backup mechanism. However, previous studies have shown that the BHR can habituate in vivo. Thus, habituation reduces sensory feedback, so the role of the pons, and specifically the KF, for IE phase transition may increase dramatically. Pontine-mediated control of the IE phase transition is not completely understood. In the present review, we discuss existing models for ponto-medullary interaction that may be involved in the control of inspiratory duration and IE transition. We also present intracellular recordings of pontine respiratory units derived from an in situ intra-arterially perfused brainstem preparation of rats. With the absence of lung inflation, this preparation generates a normal respiratory pattern and many of the recorded pontine units demonstrated phasic respiratory-related activity. The analysis of changes in membrane potentials of pontine respiratory neurons has allowed us to propose a number of pontine-medullary interactions not considered before. The involvement of these putative interactions in pontine-mediated control of IE phase transitions is discussed.
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Affiliation(s)
- Michael Mörschel
- Department of Neuro- and Sensory Physiology, University Medicine Göttingen, Georg August University, Humboldtallee 23, 37073 Göttingen, Germany
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Dutschmann M, Mörschel M, Rybak IA, Dick TE. Learning to breathe: control of the inspiratory-expiratory phase transition shifts from sensory- to central-dominated during postnatal development in rats. J Physiol 2009; 587:4931-48. [PMID: 19703965 DOI: 10.1113/jphysiol.2009.174599] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The hallmark of the dynamic regulation of the transitions between inspiration and expiration is the timing of the inspiratory off-switch (IOS) mechanisms. IOS is mediated by pulmonary vagal afferent feedback (Breuer-Hering reflex) and by central interactions involving the Kölliker-Fuse nuclei (KFn). We hypothesized that the balance between these two mechanisms controlling IOS may change during postnatal development. We tested this hypothesis by comparing neural responses to repetitive rhythmic vagal stimulation, at a stimulation frequency that paces baseline breathing, using in situ perfused brainstem preparations of rats at different postnatal ages. At ages < P15 (P, postnatal days), phrenic nerve activity (PNA) was immediately paced and entrained to the afferent input and this pattern remained unchanged by repetitive stimulations, indicating that vagal input stereotypically dominated the control of IOS. In contrast, PNA entrainment at > P15 was initially insignificant, but increased after repetitive vagal stimulation or lung inflation. This progressive adaption of PNA to the pattern of the sensory input was accompanied by the emergence of anticipatory centrally mediated IOS preceding the stimulus trains. The anticipatory IOS was blocked by bilateral microinjections of NMDA receptor antagonists into the KFn and PNA was immediately paced and entrained, as it was seen at ages < P15. We conclude that as postnatal maturation advances, synaptic mechanisms involving NMDA receptors in the KFn can override the vagally evoked IOS after 'training' using repetitive stimulation trials. The anticipatory IOS may imply a hitherto undescribed form of pattern learning and recall in convergent sensory and central synaptic pathways that mediate IOS.
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Affiliation(s)
- Mathias Dutschmann
- Institute for Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, UK.
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24
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Arata A. Respiratory activity of the neonatal dorsolateral pons in vitro. Respir Physiol Neurobiol 2009; 168:144-52. [PMID: 19616645 DOI: 10.1016/j.resp.2009.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 07/07/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022]
Abstract
The lateral and medial parabrachial and the Kölliker-Fuse nuclei (NPB/KF) are well known respiratory modulating centers in adulthood, but their role in neonates is largely unknown. We examined the role of the NPB/KF using hemi-sectioned pons-brainstem-spinal cord preparations in neonatal rats. Electrical stimulation applied at various intensities and delays in relation to the onset of spontaneous inspiratory C4 bursts, evoked transient depression or termination of C4 activity. This depression/termination was greatly attenuated either after perfusion of the NMDA-receptor antagonists (MK-801 or APV) or after microinjecting MK-801 into NPB/KF. Furthermore systemic application of the GABA-A receptor antagonist bicuculline reduced NPB/KF evoked inhibition of the C4 burst. Finally, we identified inspiratory, tonic inspiratory, expiratory, and inspiratory-expiratory (I-E) neurons which was major in the recorded neurons in the NPB/KF using the whole-cell patch-clamp method. MK-801 significantly decreased the driving potential and burst duration of I-E neurons. We conclude that neonatal NPB/KF mediated inspiratory off-switch operates on similar synaptic mechanisms as an adult.
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Affiliation(s)
- Akiko Arata
- Laboratory for Memory and Learning, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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Dutschmann M, Mörschel M, Reuter J, Zhang W, Gestreau C, Stettner GM, Kron M. Postnatal emergence of synaptic plasticity associated with dynamic adaptation of the respiratory motor pattern. Respir Physiol Neurobiol 2009; 164:72-9. [PMID: 18620081 DOI: 10.1016/j.resp.2008.06.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 06/15/2008] [Accepted: 06/16/2008] [Indexed: 01/10/2023]
Abstract
The shape of the three-phase respiratory motor pattern (inspiration, postinspiration, late expiration) is controlled by a central pattern generator (CPG) located in the ponto-medullary brainstem. Synaptic interactions between and within specific sub-compartments of the CPG are subject of intensive research. This review addresses the neural control of postinspiratory activity as the essential determinant of inspiratory/expiratory phase duration. The generation of the postinspiratory phase depends on synaptic interaction between neurones of the nucleus tractus solitarii (NTS), which relay afferent inputs from pulmonary stretch receptors, and the pontine Kölliker-Fuse nucleus (KF) as integral parts of the CPG. Both regions undergo significant changes during the first three postnatal weeks in rodents. Developmental changes in glutamatergic synaptic functions and its modulation by brain-derived neurotrophic factor may have implications in synaptic plasticity within the NTS/KF axis. We propose that dependent on these developmental changes, the CPG becomes permissive for short- and long-term plasticity associated with environmental, metabolic and behavioural adaptation of the breathing pattern.
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Affiliation(s)
- Mathias Dutschmann
- CNRS UMR 6231, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, Faculté Saint Jérôme, Case 362, 13397 Marseille Cedex 20, France.
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Takakura AC, Moreira TS, West GH, Gwilt JM, Colombari E, Stornetta RL, Guyenet PG. GABAergic pump cells of solitary tract nucleus innervate retrotrapezoid nucleus chemoreceptors. J Neurophysiol 2007; 98:374-81. [PMID: 17460107 DOI: 10.1152/jn.00322.2007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) contains central respiratory chemoreceptors that are inhibited by activation of slowly adapting pulmonary stretch receptors (SARs). Here we examine whether RTN inhibition by lung inflation could be mediated by a direct projection from SAR second-order neurons (pump cells). Pump cells (n = 56 neurons, 13 rats) were recorded in the nucleus of solitary tract (NTS) of halothane-anesthetized rats with intact vagus nerves. Pump cells had discharges that coincided with lung inflation as monitored by the tracheal pressure. Their activity increased when end-expiratory pressure was raised and stopped instantly when ventilation was interrupted in expiration. Many pump cells could be antidromically activated from RTN (12/36). Nine of those were labeled with biotinamide. Of these nine cells, eight contained glutamic acid decarboxylase 67 (GAD67) mRNA and seven were found to reside in the lower half of the interstitial subnucleus of NTS (iNTS). Using the retrograde tracer cholera toxin-B, we confirmed that neurons located in or close to iNTS innervate RTN (two rats). Many such neurons contained GAD67 mRNA and a few contained glycine transporter2 (GLYT2) mRNA. Anterograde tract tracing with biotinylated dextranamide (four rats) applied to iNTS also confirmed that this region innervates RTN by a predominantly GABAergic projection. This work confirms that many rat NTS pump cells are located in and around the interstitial subnucleus at area postrema level. We demonstrate that a GABAergic subset of these pump cells innervates the RTN region. We conclude that these inhibitory neurons probably contact RTN chemoreceptors and mediate their inhibition by lung inflation.
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Affiliation(s)
- Ana C Takakura
- Department of Pharmacology, University of Virginia Health System, Charlottesville, VA 22908-0735, USA
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Dutschmann M, Herbert H. The Kölliker-Fuse nucleus gates the postinspiratory phase of the respiratory cycle to control inspiratory off-switch and upper airway resistance in rat. Eur J Neurosci 2006; 24:1071-84. [PMID: 16930433 DOI: 10.1111/j.1460-9568.2006.04981.x] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Lesion or pharmacological manipulation of the dorsolateral pons can transform the breathing pattern to apneusis (pathological prolonged inspiration). Apneusis reflects a disturbed inspiratory off-switch mechanism (IOS) leading to a delayed phase transition from inspiration to expiration. Under intact conditions the IOS is irreversibly mediated via activation of postinspiratory (PI) neurons within the respiratory network. In parallel, populations of laryngeal premotoneurons manifest the IOS by a brief glottal constriction during the PI phase. We investigated effects of pontine excitation (glutamate injection) or temporary lesion after injection of a GABA-receptor agonist (isoguvacine) on the strength of PI-pool activity determined from respiratory motor outputs or kinesiological measurements of laryngeal resistance in a perfused brainstem preparation. Glutamate microinjections into distinct parts of the pontine Kölliker-Fuse nucleus (KF) evoked a tonic excitation of PI-motor activity or sustained laryngeal constriction accompanied by prolongation of the expiratory phase. Subsequent isoguvacine microinjections at the same loci abolished PI-motor or laryngeal constrictor activity, triggered apneusis and established a variable and decreased breathing frequency. In summary, we revealed that excitation or inhibition of defined areas within the KF activated and blocked PI activity and, consequently, IOS. Therefore, we conclude, first, that descending KF inputs are essential to gate PI activity required for a proper pattern formation and phase control within the respiratory network, at least during absence of pulmonary stretch receptor activity and, secondly, that the KF contains large numbers of laryngeal PI premotor neurons that might have a key role in the regulation of upper airway resistance during reflex control and vocalization.
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Affiliation(s)
- Mathias Dutschmann
- Department of Neuro and Sensory Physiology, Georg August University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
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Kubin L, Alheid GF, Zuperku EJ, McCrimmon DR. Central pathways of pulmonary and lower airway vagal afferents. J Appl Physiol (1985) 2006; 101:618-27. [PMID: 16645192 PMCID: PMC4503231 DOI: 10.1152/japplphysiol.00252.2006] [Citation(s) in RCA: 321] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung sensory receptors with afferent fibers coursing in the vagus nerves are broadly divided into three groups: slowly (SAR) and rapidly (RAR) adapting stretch receptors and bronchopulmonary C fibers. Central terminations of each group are found in largely nonoverlapping regions of the caudal half of the nucleus of the solitary tract (NTS). Second order neurons in the pathways from these receptors innervate neurons located in respiratory-related regions of the medulla, pons, and spinal cord. The relative ease of selective activation of SARs, and to a lesser extent RARs, has allowed for more complete physiological and morphological characterization of the second and higher order neurons in these pathways than for C fibers. A subset of NTS neurons receiving afferent input from SARs (termed pump or P-cells) mediates the Breuer-Hering reflex and inhibits neurons receiving afferent input from RARs. P-cells and second order neurons in the RAR pathway also provide inputs to regions of the ventrolateral medulla involved in control of respiratory motor pattern, i.e., regions containing a predominance of bulbospinal premotor neurons, as well as regions containing respiratory rhythm-generating neurons. Axon collaterals from both P-cells and RAR interneurons, and likely from NTS interneurons in the C-fiber pathway, project to the parabrachial pontine region where they may contribute to plasticity in respiratory control and integration of respiratory control with other systems, including those that provide for voluntary control of breathing, sleep-wake behavior, and emotions.
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Affiliation(s)
- Leszek Kubin
- Dept. of Physiology-M211, Feinberg School of Medicine, Northwestern Univ., 303 E. Chicago Ave., Chicago, IL 60611-3008, USA
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