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Kakinuma Y. Non-neuronal cholinergic system in the heart influences its homeostasis and an extra-cardiac site, the blood-brain barrier. Front Cardiovasc Med 2024; 11:1384637. [PMID: 38601043 PMCID: PMC11004362 DOI: 10.3389/fcvm.2024.1384637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 03/18/2024] [Indexed: 04/12/2024] Open
Abstract
The non-neuronal cholinergic system of the cardiovascular system has recently gained attention because of its origin. The final product of this system is acetylcholine (ACh) not derived from the parasympathetic nervous system but from cardiomyocytes, endothelial cells, and immune cells. Accordingly, it is defined as an ACh synthesis system by non-neuronal cells. This system plays a dispensable role in the heart and cardiomyocytes, which is confirmed by pharmacological and genetic studies using murine models, such as models with the deletion of vesicular ACh transporter gene and modulation of the choline acetyltransferase (ChAT) gene. In these models, this system sustained the physiological function of the heart, prevented the development of cardiac hypertrophy, and negatively regulated the cardiac metabolism and reactive oxygen species production, resulting in sustained cardiac homeostasis. Further, it regulated extra-cardiac organs, as revealed by heart-specific ChAT transgenic (hChAT tg) mice. They showed enhanced functions of the blood-brain barrier (BBB), indicating that the augmented system influences the BBB through the vagus nerve. Therefore, the non-neuronal cardiac cholinergic system indirectly influences brain function. This mini-review summarizes the critical cardiac phenotypes of hChAT tg mice and focuses on the effect of the system on BBB functions. We discuss the possibility that a cholinergic signal or vagus nerve influences the expression of BBB component proteins to consolidate the barrier, leading to the downregulation of inflammatory responses in the brain, and the modulation of cardiac dysfunction-related effects on the brain. This also discusses the possible interventions using the non-neuronal cardiac cholinergic system.
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Affiliation(s)
- Yoshihiko Kakinuma
- Department of Bioregulatory Science, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
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2
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Liu TT, Chen SP, Wang SJ, Yen JC. Vagus nerve stimulation inhibits cortical spreading depression via glutamate-dependent TrkB activation mechanism in the nucleus tractus solitarius. Cephalalgia 2024; 44:3331024241230466. [PMID: 38329067 DOI: 10.1177/03331024241230466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
BACKGROUND Vagus nerve stimulation (VNS) was recently found to inhibit cortical spreading depression (CSD), the underlying mechanism of migraine aura, through activation of the nucleus tractus solitarius (NTS), locus coeruleus (LC) and dorsal raphe nucleus (DRN). The molecular mechanisms underlying the effect of VNS on CSD in these nuclei remain to be explored. We hypothesized that VNS may activate glutamate receptor-mediated tropomyosin kinase B (TrkB) signaling in the NTS, thereby facilitating the noradrenergic and serotonergic neurotransmission to inhibit CSD. METHODS To investigate the role of TrkB and glutamate receptors in non-invasive VNS efficacy on CSD, a validated KCl-evoked CSD rat model coupled with intra-NTS microinjection of selective antagonists, immunoblot and immunohistochemistry was employed. RESULTS VNS increased TrkB phosphorylation in the NTS. Inhibition of intra-NTS TrkB abrogated the suppressive effect of VNS on CSD and CSD-induced cortical neuroinflammation. TrkB was found colocalized with glutamate receptors in NTS neurons. Inhibition of glutamate receptors in the NTS abrogated VNS-induced TrkB activation. Moreover, the blockade of TrkB in the NTS attenuated VNS-induced activation of the LC and DRN. CONCLUSIONS VNS induces the activation of glutamate receptor-mediated TrkB signaling in the NTS, which might modulate serotonergic and norepinephrinergic innervation to the cerebral cortex to inhibit CSD and cortical inflammation.
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Affiliation(s)
- Tzu-Ting Liu
- Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Pin Chen
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of Translational Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shuu-Jiun Wang
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jiin-Cherng Yen
- Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
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Tsai SF, Kuo YM. The Role of Central Oxytocin in Autonomic Regulation. CHINESE J PHYSIOL 2024; 67:3-14. [PMID: 38780268 DOI: 10.4103/ejpi.ejpi-d-23-00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/10/2023] [Indexed: 05/25/2024] Open
Abstract
Oxytocin (OXT), a neuropeptide originating from the hypothalamus and traditionally associated with peripheral functions in parturition and lactation, has emerged as a pivotal player in the central regulation of the autonomic nervous system (ANS). This comprehensive ANS, comprising sympathetic, parasympathetic, and enteric components, intricately combines sympathetic and parasympathetic influences to provide unified control. The central oversight of sympathetic and parasympathetic outputs involves a network of interconnected regions spanning the neuroaxis, playing a pivotal role in the real-time regulation of visceral function, homeostasis, and adaptation to challenges. This review unveils the significant involvement of the central OXT system in modulating autonomic functions, shedding light on diverse subpopulations of OXT neurons within the paraventricular nucleus of the hypothalamus and their intricate projections. The narrative progresses from the basics of central ANS regulation to a detailed discussion of the central controls of sympathetic and parasympathetic outflows. The subsequent segment focuses specifically on the central OXT system, providing a foundation for exploring the central role of OXT in ANS regulation. This review synthesizes current knowledge, paving the way for future research endeavors to unravel the full scope of autonomic control and understand multifaceted impact of OXT on physiological outcomes.
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Affiliation(s)
- Sheng-Feng Tsai
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Min Kuo
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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4
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Fadil R, Huether AXA, Sadeghian F, Verma AK, Blaber AP, Lou JS, Tavakolian K. The Effect of Skeletal Muscle-Pump on Blood Pressure and Postural Control in Parkinson's Disease. Cardiovasc Eng Technol 2023; 14:755-773. [PMID: 37749359 DOI: 10.1007/s13239-023-00685-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 09/06/2023] [Indexed: 09/27/2023]
Abstract
PURPOSE Activation of the calf (gastrocnemius and soleus) and tibialis anterior muscles play an important role in blood pressure regulation (via muscle-pump mechanism) and postural control. Parkinson's disease is associated with calf (and tibialis anterior muscles weakness and stiffness, which contribute to postural instability and associated falls. In this work, we studied the role of the medial and lateral gastrocnemius, tibialis anterior, and soleus muscle contractions in maintaining blood pressure and postural stability in Parkinson's patients and healthy controls during standing. In addition, we investigated whether the activation of the calf and tibialis anterior muscles is baroreflex dependent or postural-mediated. METHODS We recorded electrocardiogram, blood pressure, center of pressure as a measure of postural sway, and muscle activity from the medial and lateral gastrocnemius, tibialis anterior, and soleus muscles from twenty-six Parkinson's patients and eighteen sex and age-matched healthy controls during standing and with eyes open. The interaction and bidirectional causalities between the cardiovascular, musculoskeletal, and postural variables were studied using wavelet transform coherence and convergent cross-mapping techniques, respectively. RESULTS Parkinson's patients experienced a higher postural sway and demonstrated mechanical muscle-pump dysfunction of all individual leg muscles, all of which contribute to postural instability. Moreover, our results showed that coupling between the cardiovascular, musculoskeletal, and postural variables is affected by Parkinson's disease while the contribution of the calf and tibialis anterior muscles is greater for blood pressure regulation than postural sway. CONCLUSION The outcomes of this study could assist in the development of appropriate physical exercise programs that target lower limb muscles to improve the muscle-pump function and reduce postural instability in Parkinson's disease.
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Affiliation(s)
- Rabie Fadil
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, USA
| | - Asenath X A Huether
- Parkinson Disease Research Laboratory, Department of Neurology, Sanford Health, Fargo, ND, USA
| | - Farshid Sadeghian
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Ajay K Verma
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, USA
| | - Andrew P Blaber
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Jau-Shin Lou
- Parkinson Disease Research Laboratory, Department of Neurology, Sanford Health, Fargo, ND, USA
- Department of Neurology, University of North Dakota, School of Medicine, and Health Sciences, Grand Forks, USA
| | - Kouhyar Tavakolian
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, USA.
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
- Biomedical Engineering Program, University of North Dakota, 243 Centennial Drive, Upson Hall II, Room 11, Grand Forks, ND, 58202, USA.
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Alam MJ, Chen JDZ. Non-invasive neuromodulation: an emerging intervention for visceral pain in gastrointestinal disorders. Bioelectron Med 2023; 9:27. [PMID: 37990288 PMCID: PMC10664460 DOI: 10.1186/s42234-023-00130-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023] Open
Abstract
Gastrointestinal (GI) disorders, which extend from the esophagus to the anus, are the most common diseases of the GI tract. Among these disorders, pain, encompassing both abdominal and visceral pain, is a predominant feature, affecting the patients' quality of life and imposing a substantial financial burden on society. Pain signals originating from the gut intricately shape brain dynamics. In response, the brain sends appropriate descending signals to respond to pain through neuronal inhibition. However, due to the heterogeneous nature of the disease and its limited pathophysiological understanding, treatment options are minimal and often controversial. Consequently, many patients with GI disorders use complementary and alternative therapies such as neuromodulation to treat visceral pain. Neuromodulation intervenes in the central, peripheral, or autonomic nervous system by alternating or modulating nerve activity using electrical, electromagnetic, chemical, or optogenetic methodologies. Here, we review a few emerging noninvasive neuromodulation approaches with promising potential for alleviating pain associated with functional dyspepsia, gastroparesis, irritable bowel syndrome, inflammatory bowel disease, and non-cardiac chest pain. Moreover, we address critical aspects, including the efficacy, safety, and feasibility of these noninvasive neuromodulation methods, elucidate their mechanisms of action, and outline future research directions. In conclusion, the emerging field of noninvasive neuromodulation appears as a viable alternative therapeutic avenue for effectively managing visceral pain in GI disorders.
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Affiliation(s)
- Md Jahangir Alam
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Jiande D Z Chen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
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Tamir-Hostovsky L, Ivanovska J, Parajón E, Patel R, Wang H, Biouss G, Ivanovski N, Belik J, Pierro A, Montandon G, Gauda EB. Maturational effect of leptin on CO 2 chemosensitivity in newborn rats. Pediatr Res 2023; 94:971-978. [PMID: 37185965 DOI: 10.1038/s41390-023-02604-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 03/28/2023] [Accepted: 04/01/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Leptin augments central CO2 chemosensitivity and stabilizes breathing in adults. Premature infants have unstable breathing and low leptin levels. Leptin receptors are on CO2 sensitive neurons in the Nucleus Tractus Solitarius (NTS) and locus coeruleus (LC). We hypothesized that exogenous leptin improves hypercapnic respiratory response in newborn rats by improving central CO2 chemosensitivity. METHODS In rats at postnatal day (p)4 and p21, hyperoxic and hypercapnic ventilatory responses, and pSTAT and SOCS3 protein expression in the hypothalamus, NTS and LC were measured before and after treatment with exogenous leptin (6 µg/g). RESULTS Exogenous leptin increased the hypercapnic response in p21 but not in p4 rats (P ≤ 0.001). At p4, leptin increased pSTAT expression only in the LC, and SOCS3 expression in the NTS and LC; while at p21 pSTAT and SOCS3 levels were higher in the hypothalamus, NTS, and LC (P ≤ 0.05). CONCLUSIONS We describe the developmental profile of the effect of exogenous leptin on CO2 chemosensitivity. Exogenous leptin does not augment central CO2 sensitivity during the first week of life in newborn rats. The translational implication of these findings is that low plasma leptin levels in premature infants may not be contributing to respiratory instability. IMPACT Exogenous leptin does not augment CO2 sensitivity during the first week of life in newborn rats, similar to the developmental period when feeding behavior is resistant to leptin. Exogenous leptin increases CO2 chemosensitivity in newborn rats after the 3rd week of life and upregulates the expression of pSTAT and SOC3 in the hypothalamus, NTS and LC. Low plasma leptin levels in premature infants are unlikely contributors to respiratory instability via decreased CO2 sensitivity in premature infants. Thus, it is highly unlikely that exogenous leptin would alter this response.
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Affiliation(s)
- Liran Tamir-Hostovsky
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Julijana Ivanovska
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Eleana Parajón
- Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rachana Patel
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Huanhuan Wang
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - George Biouss
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Farrand A, Jacquemet V, Verner R, Owens M, Beaumont E. Vagus nerve stimulation parameters evoke differential neuronal responses in the locus coeruleus. Physiol Rep 2023; 11:e15633. [PMID: 36905173 PMCID: PMC10006695 DOI: 10.14814/phy2.15633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 03/12/2023] Open
Abstract
Vagus nerve stimulation (VNS) is used to treat drug-resistant epilepsy and depression, with additional applications under investigation. The noradrenergic center locus coeruleus (LC) is vital for VNS effects; however, the impact of varying stimulation parameters on LC activation is poorly understood. This study characterized LC activation across VNS parameters. Extracellular activity was recorded in rats' left LC while 11 VNS paradigms, utilizing variable frequencies and bursting characteristics, were pseudorandomly delivered to the left cervical vagus for five cycles. Neurons' change from baseline firing rate and timing response profiles were assessed. The proportion of neurons categorized as responders over 5 VNS cycles doubled in comparison to the first VNS cycle (p < 0.001) for all VNS paradigms, demonstrating an amplification effect. The percentage of positively consistent/positive responders increased for standard VNS paradigms with frequencies ≥10 Hz and for bursting paradigms with shorter interburst intervals and more pulses per burst. The synchrony between pairs of LC neurons increased during bursting VNS but not standard paradigms. Also, the probability of evoking a direct response during bursting VNS was higher with longer interburst intervals and a higher number of pulses per burst. Standard paradigms between 10-30 Hz best positively activates LC with consistency to VNS while the best bursting paradigm to increase activity was 300 Hz, seven pulses per burst separated by 1 s. Bursting VNS was effective in increasing synchrony between pairs of neurons, suggesting a common network recruitment originating from vagal afferents. These results indicate differential activation of LC neurons depending on the VNS parameters delivered.
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Affiliation(s)
- Ariana Farrand
- Department of Biomedical SciencesQuillen College of Medicine, East Tennessee State UniversityJohnson CityTennesseeUSA
| | - Vincent Jacquemet
- Department of Pharmacology and PhysiologyInstitute of Biomedical Engineering, University of MontrealMontrealQuebecCanada
- Research CenterSacred Heart Hospital of MontrealMontrealQuebecCanada
| | - Ryan Verner
- Neuromodulation DivisionLivaNova PLCHoustonTexasUSA
| | - Misty Owens
- Department of Biomedical SciencesQuillen College of Medicine, East Tennessee State UniversityJohnson CityTennesseeUSA
| | - Eric Beaumont
- Department of Biomedical SciencesQuillen College of Medicine, East Tennessee State UniversityJohnson CityTennesseeUSA
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Barcomb K, Olah SS, Kennedy MJ, Ford CP. Properties and modulation of excitatory inputs to the locus coeruleus. J Physiol 2022; 600:4897-4916. [PMID: 36156249 PMCID: PMC9669264 DOI: 10.1113/jp283605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 09/22/2022] [Indexed: 01/12/2023] Open
Abstract
Excitatory inputs drive burst firing of locus coeruleus (LC) noradrenaline (NA) neurons in response to a variety of stimuli. Though a small number of glutamatergic LC afferents have been investigated, the overall landscape of these excitatory inputs is largely unknown. The current study used an optogenetic approach to isolate three glutamatergic afferents: the prefrontal cortex (PFC), lateral hypothalamus (LH) and periaqueductal grey (PAG). AAV5-DIO-ChR2 was injected into each region in male and female CaMKII-Cre mice and the properties of excitatory inputs on LC-NA cells were measured. Notably we found differences among these inputs. First, the pattern of axonal innervation differed between inputs such that LH afferents were concentrated in the posterior portion of the LC-NA somatic region while PFC afferents were denser in the medial dendritic region. Second, basal intrinsic properties varied for afferents, with LH inputs having the highest connectivity and the largest amplitude excitatory postsynaptic currents while PAG inputs had the lowest initial release probability. Third, while orexin and oxytocin had minimal effects on any input, dynorphin strongly inhibited excitatory inputs originating from the LH and PAG, and corticotrophin releasing factor (CRF) selectively inhibited inputs from the PAG. Overall, these results demonstrate that individual afferents to the LC have differing properties, which may contribute to the modularity of the LC and its ability to mediate various behavioural outcomes. KEY POINTS: Excitatory inputs to the locus coeruleus (LC) are important for driving noradrenaline neuron activity and downstream behaviours in response to salient stimuli, but little is known about the functional properties of different glutamate inputs that innervate these neurons We used a virus-mediated optogenetic approach to compare glutamate afferents from the prefrontal cortex (PFC), the lateral hypothalamus (LH) and the periaqueductal grey (PAG). While PFC was predicted to make synaptic inputs, we found that the LH and PAG also drove robust excitatory events in LC noradrenaline neurons. The strength, kinetics, and short-term plasticity of each input differed as did the extent of neuromodulation by both dynorphin and corticotrophin releasing factor. Thus each input displayed a unique set of basal properties and modulation by peptides. This characterization is an important step in deciphering the heterogeneity of the LC.
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Affiliation(s)
- Kelsey Barcomb
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Samantha S. Olah
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Matthew J. Kennedy
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Christopher P. Ford
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
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Fadil R, Huether AXA, Verma AK, Brunnemer R, Blaber AP, Lou JS, Tavakolian K. Effect of Parkinson’s Disease on Cardio-postural Coupling During Orthostatic Challenge. Front Physiol 2022; 13:863877. [PMID: 35755448 PMCID: PMC9214860 DOI: 10.3389/fphys.2022.863877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/06/2022] [Indexed: 11/13/2022] Open
Abstract
Cardiac baroreflex and leg muscles activation are two important mechanisms for blood pressure regulation, failure of which could result in syncope and falls. Parkinson’s disease is known to be associated with cardiac baroreflex impairment and skeletal muscle dysfunction contributing to falls. However, the mechanical effect of leg muscles contractions on blood pressure (muscle-pump) and the baroreflex-like responses of leg muscles to blood pressure changes is yet to be comprehensively investigated. In this study, we examined the involvement of the cardiac baroreflex and this hypothesized reflex muscle-pump function (cardio-postural coupling) to maintain blood pressure in Parkinson’s patients and healthy controls during an orthostatic challenge induced via a head-up tilt test. We also studied the mechanical effect of the heart and leg muscles contractions on blood pressure. We recorded electrocardiogram blood pressure and electromyogram from 21 patients with Parkinson’s disease and 18 age-matched healthy controls during supine, head-up tilt at 70°, and standing positions with eyes open. The interaction and bidirectional causalities between the cardiovascular and musculoskeletal signals were studied using wavelet transform coherence and convergent cross mapping techniques, respectively. Parkinson’s patients displayed an impaired cardiac baroreflex and a reduced mechanical effect of the heart on blood pressure during supine, tilt and standing positions. However, the effectiveness of the cardiac baroreflex decreased in both Parkinson’s patients and healthy controls during standing as compared to supine. In addition, Parkinson’s patients demonstrated cardio-postural coupling impairment along with a mechanical muscle pump dysfunction which both could lead to dizziness and falls. Moreover, the cardiac baroreflex had a limited effect on blood pressure during standing while lower limb muscles continued to contract and maintain blood pressure via the muscle-pump mechanism. The study findings highlighted altered bidirectional coupling between heart rate and blood pressure, as well as between muscle activity and blood pressure in Parkinson’s disease. The outcomes of this study could assist in the development of appropriate physical exercise programs to reduce falls in Parkinson’s disease by monitoring the cardiac baroreflex and cardio-postural coupling effect on maintaining blood pressure.
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Affiliation(s)
- Rabie Fadil
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, United States
| | - Asenath X. A. Huether
- Parkinson Disease Research Laboratory, Department of Neurology, Sanford Health, Fargo, ND, United States
| | - Ajay K. Verma
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, United States
| | - Robert Brunnemer
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, United States
| | - Andrew P. Blaber
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Jau-Shin Lou
- Parkinson Disease Research Laboratory, Department of Neurology, Sanford Health, Fargo, ND, United States
- School of Medicine and Health Sciences, Department of Neurology, University of North Dakota, Grand Forks, ND, United States
| | - Kouhyar Tavakolian
- Biomedical Engineering Program, University of North Dakota, Grand Forks, ND, United States
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- *Correspondence: Kouhyar Tavakolian,
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Forstenpointner J, Maallo AMS, Elman I, Holmes S, Freeman R, Baron R, Borsook D. The Solitary Nucleus Connectivity to Key Autonomic Regions in Humans MRI and Literature based Considerations. Eur J Neurosci 2022; 56:3938-3966. [PMID: 35545280 DOI: 10.1111/ejn.15691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/03/2022]
Abstract
The nucleus tractus solitarius (NTS), is a key brainstem structure relaying interoceptive peripheral information to the interrelated brain centers for eliciting rapid autonomic responses and for shaping longer-term neuroendocrine and motor patterns. Structural and functional NTS' connectivity has been extensively investigated in laboratory animals. But there is limited information about NTS' connectome in humans. Using MRI, we examined diffusion and resting state data from 20 healthy participants in the Human Connectome Project. The regions within the brainstem (n=8), subcortical (n=6), cerebellar (n=2) and cortical (n=5) parts of the brain were selected via a systematic review of the literature and their white matter NTS connections were evaluated via probabilistic tractography along with functional and directional (i.e., Granger-causality) analyses. The underlying study confirms previous results from animal models and provides novel aspects on NTS integration in humans. Two key findings can be summarized: (i) the NTS predominantly processes afferent input and (ii) a lateralization towards a predominantly left-sided NTS processing. Our results lay the foundations for future investigations into the NTS' tripartite role comprised of interoreceptors' input integration, the resultant neurochemical outflow and cognitive/affective processing. The implications of these data add to the understanding of NTS' role in specific aspects of autonomic functions.
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Affiliation(s)
- Julia Forstenpointner
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA.,Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Anne Margarette S Maallo
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
| | - Igor Elman
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA.,Cambridge Health Alliance, Harvard Medical School, Cambridge, MA, USA
| | - Scott Holmes
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
| | - Roy Freeman
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA.,Department of Radiology and Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Osorio-Forero A, Cherrad N, Banterle L, Fernandez LMJ, Lüthi A. When the Locus Coeruleus Speaks Up in Sleep: Recent Insights, Emerging Perspectives. Int J Mol Sci 2022; 23:ijms23095028. [PMID: 35563419 PMCID: PMC9099715 DOI: 10.3390/ijms23095028] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 12/03/2022] Open
Abstract
For decades, numerous seminal studies have built our understanding of the locus coeruleus (LC), the vertebrate brain’s principal noradrenergic system. Containing a numerically small but broadly efferent cell population, the LC provides brain-wide noradrenergic modulation that optimizes network function in the context of attentive and flexible interaction with the sensory environment. This review turns attention to the LC’s roles during sleep. We show that these roles go beyond down-scaled versions of the ones in wakefulness. Novel dynamic assessments of noradrenaline signaling and LC activity uncover a rich diversity of activity patterns that establish the LC as an integral portion of sleep regulation and function. The LC could be involved in beneficial functions for the sleeping brain, and even minute alterations in its functionality may prove quintessential in sleep disorders.
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12
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Forstenpointner J, Elman I, Freeman R, Borsook D. The Omnipresence of Autonomic Modulation in Health and Disease. Prog Neurobiol 2022; 210:102218. [PMID: 35033599 DOI: 10.1016/j.pneurobio.2022.102218] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/13/2021] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
Abstract
The Autonomic Nervous System (ANS) is a critical part of the homeostatic machinery with both central and peripheral components. However, little is known about the integration of these components and their joint role in the maintenance of health and in allostatic derailments leading to somatic and/or neuropsychiatric (co)morbidity. Based on a comprehensive literature search on the ANS neuroanatomy we dissect the complex integration of the ANS: (1) First we summarize Stress and Homeostatic Equilibrium - elucidating the responsivity of the ANS to stressors; (2) Second we describe the overall process of how the ANS is involved in Adaptation and Maladaptation to Stress; (3) In the third section the ANS is hierarchically partitioned into the peripheral/spinal, brainstem, subcortical and cortical components of the nervous system. We utilize this anatomical basis to define a model of autonomic integration. (4) Finally, we deploy the model to describe human ANS involvement in (a) Hypofunctional and (b) Hyperfunctional states providing examples in the healthy state and in clinical conditions.
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Affiliation(s)
- Julia Forstenpointner
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA; Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, SH, Germany.
| | - Igor Elman
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA; Cambridge Health Alliance, Harvard Medical School, Cambridge, MA, USA
| | - Roy Freeman
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA; Departments of Psychiatry and Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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13
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Nigam M, Ayadi I, Noiray C, Branquino-Bras AC, Herraez Sanchez E, Leu-Semenescu S, Vidailhet M, Dodet P, Arnulf I. Sweet or Bland Dreams? Taste Loss in Isolated REM-Sleep Behavior Disorder and Parkinson's Disease. Mov Disord 2021; 36:2431-2435. [PMID: 34117799 DOI: 10.1002/mds.28692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Hyposmia and isolated REM sleep behavior disorder are well-established features of prodromal Parkinson's disease (PD). OBJECTIVES The objective of the present study was to evaluate whether taste loss (reported in PD and possibly suggesting brain stem involvement) is present at the isolated REM sleep behavior disorder stage. METHODS We assessed taste function using the Taste Strip Test (evaluating 4 concentrations of bitter, sweet, sour, and salty) in 44 participants with isolated REM sleep behavior disorder, 19 with PD, and 29 controls. All participants underwent video-polysomnography, standardized questionnaires, and clinical examination, including olfactory assessment. RESULTS Participants with isolated REM sleep behavior disorder and PD had lower taste scores than controls. There was no difference between isolated REM sleep behavior disorder and PD cohorts, nor was there any correlation between taste and olfaction, age, disease duration, cognition, or autonomic function. CONCLUSION This study demonstrates for the first time the presence of taste impairment in isolated REM sleep behavior disorder that is independent of olfactory dysfunction and comparable to participants with PD. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Milan Nigam
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France.,Centre for Advanced Research in Sleep Medicine, Sacré-Coeur Hospital, Montreal, Quebec, Canada.,Department of Neurosciences, University of Montreal, Montreal, Quebec, Canada
| | - Ines Ayadi
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France
| | - Camille Noiray
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France
| | - Ana Catarina Branquino-Bras
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France.,Department of Neurology - Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Erika Herraez Sanchez
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France.,Hospital Universitario La Paz, Madrid, Spain
| | - Smaranda Leu-Semenescu
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France
| | - Marie Vidailhet
- Department of Neurology, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France.,Institut du Cerveau et de la Moelle (Paris Brain Institute), Paris, France.,Sorbonne University, Paris, France
| | - Pauline Dodet
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France
| | - Isabelle Arnulf
- Sleep Disorders Unit, University Hospital Pitié-Salpêtrière, APHP-Sorbonne, Paris, France.,Institut du Cerveau et de la Moelle (Paris Brain Institute), Paris, France.,Sorbonne University, Paris, France
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14
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Liu N, Fu C, Yu H, Wang Y, Shi L, Hao Y, Yuan F, Zhang X, Wang S. Respiratory Control by Phox2b-expressing Neurons in a Locus Coeruleus-preBötzinger Complex Circuit. Neurosci Bull 2020; 37:31-44. [PMID: 32468398 DOI: 10.1007/s12264-020-00519-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
The locus coeruleus (LC) has been implicated in the control of breathing. Congenital central hypoventilation syndrome results from mutation of the paired-like homeobox 2b (Phox2b) gene that is expressed in LC neurons. The present study was designed to address whether stimulation of Phox2b-expressing LC (Phox2bLC) neurons affects breathing and to reveal the putative circuit mechanism. A Cre-dependent viral vector encoding a Gq-coupled human M3 muscarinic receptor (hM3Dq) was delivered into the LC of Phox2b-Cre mice. The hM3Dq-transduced neurons were pharmacologically activated while respiratory function was measured by plethysmography. We demonstrated that selective stimulation of Phox2bLC neurons significantly increased basal ventilation in conscious mice. Genetic ablation of these neurons markedly impaired hypercapnic ventilatory responses. Moreover, stimulation of Phox2bLC neurons enhanced the activity of preBötzinger complex neurons. Finally, axons of Phox2bLC neurons projected to the preBötzinger complex. Collectively, Phox2bLC neurons contribute to the control of breathing most likely via an LC-preBötzinger complex circuit.
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Affiliation(s)
- Na Liu
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China.,Department of Physiology, Cangzhou Medical College, Cangzhou, 061000, China
| | - Congrui Fu
- School of Nursing, Hebei Medical University, Shijiazhuang, 050000, China
| | - Hongxiao Yu
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China
| | - Yakun Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China
| | - Luo Shi
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China
| | - Yinchao Hao
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China
| | - Fang Yuan
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China
| | - Xiangjian Zhang
- Hebei Key laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000, China
| | - Sheng Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017, China.
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15
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Rodenkirch C, Wang Q. Rapid and transient enhancement of thalamic information transmission induced by vagus nerve stimulation. J Neural Eng 2020; 17:026027. [PMID: 31935689 DOI: 10.1088/1741-2552/ab6b84] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Vagus nerve stimulation (VNS) has been FDA-approved as a long-term, therapeutic treatment for multiple disorders, including pharmacoresistant epilepsy and depression. Here we elucidate the short-term effects of VNS on sensory processing. APPROACH We employed an information theoretic approach to examine the effects of VNS on thalamocortical transmission of sensory-related information along the somatosensory pathway. MAIN RESULTS We found that VNS enhanced the selectivity of the response of thalamic neurons to specific kinetic features in the stimuli, resulting in a significant increase in the efficiency and rate of stimulus-related information conveyed by thalamic spikes. VNS-induced improvements in thalamic sensory processing coincided with a decrease in thalamic burst firing. Importantly, we found VNS-induced enhancement of sensory processing had a rapid onset and offset, completely disappearing one minute after cessation of VNS. The timescales of these effects indicate against an underlying mechanism involving long-term neuroplasticity. We found several patterns of VNS (tonic, standard duty-cycle, and fast duty-cycle) all induced similar improvements in sensory processing. Under closer inspection we noticed that due to the fast timescale of VNS effects on sensory processing, standard duty-cycle VNS induced a fluctuating sensory processing state which may be sub-optimal for perceptual behavior. Fast duty-cycle VNS and continuous, tonic VNS induced quantitatively similar improvements in thalamic information transmission as standard duty-cycle VNS without inducing a fluctuating thalamic state. Further, we found the strength of VNS-induced improvements in sensory processing increased monotonically with amplitude and frequency of VNS. SIGNIFICANCE These results demonstrate, for the first time, the feasibility of utilizing specific patterns of VNS to rapidly improve sensory processing and confirm fast duty-cycle and tonic patterns as optimal for this purpose, while showing standard duty-cycle VNS causes non-optimal fluctuations in thalamic state.
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Affiliation(s)
- Charles Rodenkirch
- Department of Biomedical Engineering, Columbia University, ET351, 500 W. 120th Street, New York, NY 10027, United States of America
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16
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Vicente MC, Humphrey CM, Gargaglioni LH, Ostrowski TD. Decreased excitability of locus coeruleus neurons during hypercapnia is exaggerated in the streptozotocin-model of Alzheimer's disease. Exp Neurol 2020; 328:113250. [PMID: 32088169 DOI: 10.1016/j.expneurol.2020.113250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 10/25/2022]
Abstract
The locus coeruleus (LC) is a pontine nucleus important for respiratory control and central chemoreception. It is affected in Alzheimer's disease (AD) and alteration of LC cell function may account for respiratory problems observed in AD patients. In the current study, we tested the electrophysiological properties and CO2/pH sensitivity of LC neurons in a model for AD. Sporadic AD was induced in rats by intracerebroventricular injection of 2 mg/kg streptozotocin (STZ), which induces behavioral and molecular impairments found in AD. LC neurons were recorded using the patch clamp technique and tested for responses to CO2 (10% CO2, pH = 7.0). The majority (~60%) of noradrenergic LC neurons in adult rats were inhibited by CO2 exposure as indicated by a significant decrease in action potential (AP) discharge to step depolarizations. The STZ-AD rat model had a greater sensitivity to CO2 than controls. The increased CO2-sensitivity was demonstrated by a significantly stronger inhibition of activity during hypercapnia that was in part due to hyperpolarization of the resting membrane potential. Reduction of AP discharge in both groups was generally accompanied by lower LC network activity, depolarized AP threshold, increased AP repolarization, and increased current through a subpopulation of voltage-gated K+ channels (KV). The latter was indicated by enhanced transient KV currents particularly in the STZ-AD group. Interestingly, steady-state KV currents were reduced under hypercapnia, a change that would favor enhanced AP discharge. However, the collective response of most LC neurons in adult rats, and particularly those in the STZ-AD group, was inhibited by CO2.
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Affiliation(s)
- Mariane C Vicente
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA; Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Chuma M Humphrey
- Department of Biology, Truman State University, Kirksville, MO, USA
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Tim D Ostrowski
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA.
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17
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Magalhães KS, de Britto AA, Paton JFR, Moraes DJA. A6 neurons simultaneously modulate active expiration and upper airway resistance in rats. Exp Physiol 2019; 105:53-64. [PMID: 31675759 DOI: 10.1113/ep088164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/23/2019] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do A6 neurons modulate active expiratory and airway responses evoked by hypercapnia/acidosis? What is the main finding and its importance? Acute inhibition of A6 neurons reduced active expiratory, inspiratory and the associated oropharyngeal and laryngeal motor responses to hypercapnia/acidosis. A6 neurons provide excitatory synaptic drive contributing to the central generation of inspiratory and expiratory motor activity as well as the control of upper airway resistance. ABSTRACT During rest, inspiration is an active phenomenon, whereas expiration is passive. Under conditions of high chemical drive, such as hypercapnia/acidosis, there is an increase in inspiratory activity, expiration becomes active and upper airway resistance is reduced. The locus coeruleus noradrenergic neurons (A6 neurons) are activated when exposed to elevated CO2 /[H+ ] levels and modulate respiratory brainstem neurons regulating ventilation. However, the role of A6 neurons in the control of upper airway resistance is not fully understood. We tested the hypothesis that A6 neurons contribute to the central generation of active inspiratory and expiratory responses and the associated changes in the motor nerves controlling upper airway resistance during hypercapnia/acidosis in rats. Using a perfused brainstem-spinal cord preparation, we inhibited A6 neurons using pharmacogenetics and evaluated the active expiratory (abdominal nerve), laryngeal (cervical vagus nerve), oropharyngeal (hypoglossal nerve) and inspiratory (phrenic nerve) motor nerve responses to hypercapnia/acidosis. Acute inhibition of A6 neurons did not produce significant changes in the respiratory pattern in normocapnia. However, the hypercapnia/acidosis-induced active expiratory response and the associated changes in the motor nerves responsible for control of oropharyngeal and laryngeal resistance, as well as the inspiratory response were all reduced after inhibition of A6 neurons. Our data demonstrate that A6 neurons exert an important excitatory synaptic drive to the central generation of both active inspiratory and expiratory activities and modulate the control of upper airway resistance during hypercapnia/acidosis.
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Affiliation(s)
- Karolyne S Magalhães
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Alan A de Britto
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julian F R Paton
- Cardiovascular Autonomic Research Cluster, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Davi J A Moraes
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
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18
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Lumb KJ, Schneider JM, Ibrahim T, Rigaux A, Hasan SU. Afferent neural feedback overrides the modulating effects of arousal, hypercapnia and hypoxaemia on neonatal cardiorespiratory control. J Physiol 2018; 596:6009-6019. [PMID: 29676798 PMCID: PMC6265552 DOI: 10.1113/jp275682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/13/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Evidence obtained at whole animal, organ-system, and cellular and molecular levels suggests that afferent volume feedback is critical for the establishment of adequate ventilation at birth. As a result of the irreversible nature of the vagal ablation studies performed to date, it was difficult to quantify the roles of afferent volume input, arousal and changes in blood gas tensions on neonatal respiratory control. During reversible perineural vagal block, profound apnoeas and hypoxaemia and hypercarbia were observed, necessitating the termination of perineural blockade. Respiratory depression and apnoeas were independent of sleep state. We demonstrate that profound apnoeas and life-threatening respiratory failure in vagally denervated animals do not result from a lack of arousal or hypoxaemia. A change in sleep state and concomitant respiratory depression result from a lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period. ABSTRACT Afferent volume feedback plays a vital role in neonatal respiratory control. Mechanisms for the profound respiratory depression and life-threatening apnoeas observed in vagally denervated neonatal animals remain unclear. We investigated the roles of sleep states, hypoxic-hypercapnia and afferent volume feedback on respiratory depression using reversible perineural vagal block during the early postnatal period. Seven lambs were instrumented during the first 48 h of life to record/analyse sleep states, diaphragmatic electromyograph, arterial blood gas tensions, systemic arterial blood pressure and rectal temperature. Perineural cuffs were placed around the vagi to attain reversible blockade. Postoperatively, during the awake state, both vagi were blocked using 2% xylocaine for up to 30 min. Compared to baseline values, pHa , P a o 2 and S a o 2 decreased and P ac o 2 increased during perineural blockade (P < 0.05). Four of seven animals exhibited apnoeas of ≥20 s requiring the immediate termination of perineural blockade. Breathing rates decreased from the baseline value of 53 ± 12 to 24 ± 20 breaths min-1 during blockade despite an increased P ac o 2 (P < 0.001). Following blockade, breathing patterns returned to baseline values despite marked hypocapnia ( P ac o 2 33 ± 3 torr; P = 0.03). Respiratory depression and apnoeas were independent of sleep states. The present study provides the much needed physiological evidence indicating that profound apnoeas and life-threatening respiratory failure in vagally denervated animals do not result from a lack of arousal or hypoxaemia. Rather, a change in sleep state and concomitant respiratory depression result from a lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period.
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Affiliation(s)
- Kathleen J. Lumb
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Jennifer M. Schneider
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Thowfique Ibrahim
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Anita Rigaux
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Shabih U. Hasan
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
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19
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Lui S, Torontali Z, Tadjalli A, Peever J. Brainstem Nuclei Associated with Mediating Apnea-Induced Respiratory Motor Plasticity. Sci Rep 2018; 8:12709. [PMID: 30139983 PMCID: PMC6107593 DOI: 10.1038/s41598-018-28578-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 06/21/2018] [Indexed: 01/30/2023] Open
Abstract
The respiratory control system is plastic. It has a working memory and is capable of retaining how respiratory stimuli affect breathing by regulating synaptic strength between respiratory neurons. For example, repeated airway obstructions trigger a form of respiratory plasticity that strengthens inspiratory activity of hypoglossal (XII) motoneurons. This form of respiratory plasticity is known as long-term facilitation (LTF) and requires noradrenaline released onto XII motoneurons. However, the brainstem regions responsible for this form of LTF remain unidentified. Here, we used electrophysiology, neuropharmacology and immunohistochemistry in adult rats to identify the brainstem regions involved in mediating LTF. First, we show that repeated airway obstructions induce LTF of XII motoneuron activity and that inactivation of the noradrenergic system prevents LTF. Second, we show that noradrenergic cells in the locus coeruleus (LC), which project to XII motoneurons, are recruited during LTF induction. Third, we show that targeted inactivation of noradrenergic LC cells during LTF induction prevents LTF. And lastly, we show that the nucleus tractus solitarius (NTS), which has known projections to the LC, is critical for LTF because its inactivation prevents LTF. Our results suggest that both the LC and NTS are involved in mediating apnea-induced LTF, and we hypothesize that a NTS → LC → XII circuit mechanism mediates this form of respiratory motor plasticity.
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Affiliation(s)
- Simon Lui
- Centre for Biological Timing and Cognition, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.,Departments of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Zoltan Torontali
- Centre for Biological Timing and Cognition, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.,Departments of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Arash Tadjalli
- Centre for Biological Timing and Cognition, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.,Departments of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - John Peever
- Centre for Biological Timing and Cognition, University of Toronto, Toronto, Ontario, M5S 3G5, Canada. .,Departments of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada. .,Department of Physiology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.
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20
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Kawai Y. Differential Ascending Projections From the Male Rat Caudal Nucleus of the Tractus Solitarius: An Interface Between Local Microcircuits and Global Macrocircuits. Front Neuroanat 2018; 12:63. [PMID: 30087599 PMCID: PMC6066510 DOI: 10.3389/fnana.2018.00063] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/11/2018] [Indexed: 11/18/2022] Open
Abstract
To integrate and broadcast neural information, local microcircuits and global macrocircuits interact within certain specific nuclei of the central nervous system. The structural and functional architecture of this interaction was determined for the caudal nucleus of the tractus solitarius (NTS) at the level of the area postrema (AP), a relay station of peripheral viscerosensory information that is processed and conveyed to brain regions concerned with autonomic-affective and other interoceptive reflexive functions. Axon collaterals of most small NTS cells (soma <150 μm2) establish excitatory or inhibitory local microcircuits likely to control the activity of nearby NTS cells and to transfer peripheral signals to efferent projection neurons. At least two types of cells that constitute efferent pathways from the caudal NTS (cNTS) were distinguished: (1) a greater numbers of small cells, seemingly forming local excitatory microcircuits via recurrent axon collaterals, that project specifically and unidirectionally to the lateral parabrachial nucleus; and (2) a much smaller numbers of cells likely to establish multiple global connections, mostly via the medial forebrain bundle (MFB) or the dorsal longitudinal fascicle (DLF), with a wide range of brain regions, including the ventrolateral medulla (VLM), hypothalamus, central nucleus of the amygdala (ACe), bed nucleus of the stria terminalis (BNST), spinal cord dorsal horn, brainstem reticular formation, locus coeruleus (LC), periaqueductal gray (PAG) and periventricular diencephalon (including the epithalamus). The evidence presented here suggests that distinct cNTS cell types distinguished by projection pattern and related structural and functional features participate differentially in the computation of viscerosensory information and coordination of global macro-networks in a highly organized manner.
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Affiliation(s)
- Yoshinori Kawai
- Department of Anatomy, Jikei University School of Medicine, Tokyo, Japan.,Center for Neuroscience of Pain, Jikei University School of Medicine, Tokyo, Japan
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21
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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