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Fawley JA, Hegarty DM, Aicher SA, Beaumont E, Andresen MC. Dedicated C-fiber vagal sensory afferent pathways to the paraventricular nucleus of the hypothalamus. Brain Res 2021; 1769:147625. [PMID: 34416255 DOI: 10.1016/j.brainres.2021.147625] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/24/2021] [Accepted: 08/12/2021] [Indexed: 12/22/2022]
Abstract
The nucleus of the solitary tract (NTS) receives viscerosensory information from the vagus nerve to regulate diverse homeostatic reflex functions. The NTS projects to a wide network of other brain regions, including the paraventricular nucleus of the hypothalamus (PVN). Here we examined the synaptic characteristics of primary afferent pathways to PVN-projecting NTS neurons in rat brainstem slices.Expression of the Transient Receptor Potential Vanilloid receptor (TRPV1+ ) distinguishes C-fiber afferents within the solitary tract (ST) from A-fibers (TRPV1-). We used resiniferatoxin (RTX), a TRPV1 agonist, to differentiate the two. The variability in the latency (jitter) of evoked excitatory postsynaptic currents (ST-EPSCs) distinguished monosynaptic from polysynaptic ST-EPSCs. Rhodamine injected into PVN was retrogradely transported to identify PVN-projecting NTS neurons within brainstem slices. Graded shocks to the ST elicited all-or-none EPSCs in rhodamine-positive NTS neurons with latencies that had either low jitter (<200 µs - monosynaptic), high jitter (>200 µs - polysynaptic inputs) or both. RTX blocked ST-evoked TRPV1 + EPSCs whether mono- or polysynaptic. Most PVN-projecting NTS neurons (17/21 neurons) had at least one input polysynaptically connected to the ST. Compared to unlabeled NTS neurons, PVN-projecting NTS neurons were more likely to receive indirect inputs and be higher order. Surprisingly, sEPSC rates for PVN-projecting neurons were double that of unlabeled NTS neurons. The ST synaptic responses for PVN-projecting NTS neurons were either all TRPV1+ or all TRPV1-, including neurons that received both direct and indirect inputs. Overall, PVN-projecting NTS neurons received direct and indirect vagal afferent information with strict segregation regarding TRPV1 expression.
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Affiliation(s)
- Jessica A Fawley
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Deborah M Hegarty
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Sue A Aicher
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Michael C Andresen
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States.
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Sasaki K, Inoue T, Inoue T, Nishijima Y, Endo T, Ezura M, Uenohara H, Niizuma K, Tominaga T. Intractable Hiccups as the Primary Symptom of a Perimedullary Arteriovenous Fistula at the Craniocervical Junction. World Neurosurg 2020; 141:64-68. [PMID: 32526360 DOI: 10.1016/j.wneu.2020.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Hiccups are a well-known short-term phenomenon in daily life. If they persist or become intractable, they may be a primary symptom of a disease. Recent studies identified the medulla oblongata as the neuroanatomic center of the hiccup reflex arc. In previous cases, an isolated lesion at the dorsal side of the medulla oblongata induced intractable hiccups. CASE DESCRIPTION We herein describe a patient with a perimedullary arteriovenous fistula (PMAVF) at the craniocervical junction who had intractable hiccups. A 70-year-old male presented with a 3-year history of intractable hiccups that continued for a few days every week. An initial examination failed to identify the underlying cause, and neither medicine nor self-treatment attenuated his symptoms. Intracranial T2-weighted magnetic resonance imaging showed a hyperintensity area within the dorsolateral medulla and flow voids along the dorsal side of the cervical spine. Angiography revealed PMAVF fed by the left C1 radiculomedullary artery. Obliteration of the fistula was performed, after which intractable hiccups had completely disappeared within 1 week. CONCLUSIONS This is the first case report of PMAVF at the craniocervical junction presenting with intractable hiccups that suggested a lesion in the dorsal side of the medulla. The mechanisms underlying hiccups are also discussed.
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Affiliation(s)
- Keisuke Sasaki
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan; Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan
| | - Tomoo Inoue
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan; Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan.
| | - Takashi Inoue
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan
| | - Yasuo Nishijima
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan
| | - Toshiki Endo
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan; Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan
| | - Masayuki Ezura
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan
| | - Hiroshi Uenohara
- Department of Neurosurgery, National Health Organization, Sendai Medical Center, Sendai, Miyagi, Japan
| | - Kuniyasu Niizuma
- Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan; Department of Neurosurgery and Neurosurgical Engineering and Translational Neuroscience, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan; Department of Neurosurgery and Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan
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Jaster JH, Zamecnik J, Giannì AB, Ottaviani G. CO 2-related vasoconstriction superimposed on ischemic medullary brain autonomic nuclei may contribute to sudden death. Cardiovasc Pathol 2018; 38:42-45. [PMID: 30466068 DOI: 10.1016/j.carpath.2018.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/24/2018] [Accepted: 10/19/2018] [Indexed: 10/28/2022] Open
Abstract
INTRODUCTION In 2015, a multinational randomized controlled phase IV clinical trial of adaptive servoventilation for the management of heart failure with central sleep apnea was halted in progress because more patients in the study group were dying than in the control group. One year later, another large clinical trial reported results on the effectiveness of continuous positive airway pressure (CPAP) in preventing sudden death and other cardiovascular events such as heart attack and stroke in patients with preexisting vascular disease as well as obstructive sleep apnea. BACKGROUND Sudden unexpected death has been associated with many types of small and nonmalignant medullary brain lesions, like demyelination plaques - largely asymptomatic until they caused sudden death. Many such medullary lesions, typically without hemorrhage or mass effect, have in themselves been previously considered relatively harmless - in cases where they have been known to be present. DISCUSSION Why did not the improved pulmonary ventilation and subsequently improved gas exchange provided during the CPAP and servoventilation clinical trials help to resolve any ischemic lesions that may have been present both in the heart and in the medulla, thereby tending to normalize interactions between the vagal neural structures and the heart? CO2 is a potent dilator of brain vasculature, thereby increasing blood flow to the brain. When ventilation is increased, even if only to improve it back toward normal from a depressed steady-state level, the alveolar partial pressure of carbon dioxide is decreased, likely resulting in a converse relative vasoconstriction in the brain, thereby reducing blood flow in the brain, especially in watershed areas like the solitary tract nucleus. In normal physiology, this is demonstrated impressively by the ability of hyperventilation to induce loss of consciousness. CONCLUSIONS The findings of several clinical trials recently reported, taken together with neuropathology case studies reported elsewhere, suggest that additional research is warranted in regard to the mechanisms by which focal medullary autonomic brain ischemia may be related to sudden death in general medical illnesses - and how it may additionally be influenced by changes in arterial CO2 levels.
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Affiliation(s)
- J Howard Jaster
- London Corporation, 1655 Harbert Avenue, Memphis, TN 38104, USA
| | - Josef Zamecnik
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University, 11636 Prague, Czech Republic
| | - Aldo Bruno Giannì
- Maxillofacial and Dental Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano, 20122 Milan, Italy; "Lino Rossi" Research Center, Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20122 Milan, Italy
| | - Giulia Ottaviani
- "Lino Rossi" Research Center, Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20122 Milan, Italy.
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Abstract
PURPOSE OF REVIEW The goal of this review is to assess the evidence that activation of angiotensin type 2 receptors (AT2R) in the brain can lower blood pressure and possibly constitute an endogenous anti-hypertensive mechanism. RECENT FINDINGS Recent studies that detail the location of AT2R in the brain, particularly within or near cardiovascular control centers, mesh well with findings from pharmacological and gene transfer studies which demonstrate that activation of central AT2R can influence cardiovascular regulation. Collectively, these studies indicate that selective activation of brain AT2R causes moderate decreases in blood pressure in normal animals and more profound anti-hypertensive effects, along with restoration of baroreflex function, in rodent models of neurogenic hypertension. These findings have opened the door to studies that can (i) assess the role of specific AT2R neuron populations in depressing blood pressure, (ii) determine the relevance of such mechanisms, and (iii) investigate interactions between AT2R and depressor angiotensin-(1-7)/Mas mechanisms in the brain.
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Affiliation(s)
- Annette D de Kloet
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, 1600 SW Archer Road, Box 100274, Gainesville, FL, 32610-0274, USA
| | - Ulrike M Steckelings
- IMM - Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Colin Sumners
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, 1600 SW Archer Road, Box 100274, Gainesville, FL, 32610-0274, USA.
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Poliacek I, Simera M, Veternik M, Kotmanova Z, Bolser DC, Machac P, Jakus J. Role of the dorsomedial medulla in suppression of cough by codeine in cats. Respir Physiol Neurobiol 2017; 246:59-66. [PMID: 28778649 DOI: 10.1016/j.resp.2017.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/23/2017] [Accepted: 07/28/2017] [Indexed: 12/24/2022]
Abstract
The modulation of cough by microinjections of codeine in 3 medullary regions, the solitary tract nucleus rostral to the obex (rNTS), caudal to the obex (cNTS) and the lateral tegmental field (FTL) was studied. Experiments were performed on 27 anesthetized spontaneously breathing cats. Electromyograms (EMG) were recorded from the sternal diaphragm and expiratory muscles (transversus abdominis and/or obliquus externus; ABD). Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airways. Bilateral microinjections of codeine (3.3 or 33mM, 54±16nl per injection) in the cNTS had no effect on cough, while those in the rNTS and in the FTL reduced coughing. Bilateral microinjections into the rNTS (3.3mM codeine, 34±1 nl per injection) reduced the number of cough responses by 24% (P<0.05), amplitudes of diaphragm EMG by 19% (P<0.01), of ABD EMG by 49% (P<0.001) and of expiratory esophageal pressure by 56% (P<0.001). Bilateral microinjections into the FTL (33mM codeine, 33±3 nl per injection) induced reductions in cough expiratory as well as inspiratory EMG amplitudes (ABD by 60% and diaphragm by 34%; P<0.01) and esophageal pressure amplitudes (expiratory by 55% and inspiratory by 26%; P<0.001 and 0.01, respectively). Microinjections of vehicle did not significantly alter coughing. Breathing was not affected by microinjections of codeine. These results suggest that: 1) codeine acts within the rNTS and the FTL to reduce cough in the cat, 2) the neuronal circuits in these target areas have unequal sensitivity to codeine and/or they have differential effects on spatiotemporal control of cough, 3) the cNTS has a limited role in the cough suppression induced by codeine in cats.
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Affiliation(s)
- Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Michal Simera
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia.
| | - Marcel Veternik
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Zuzana Kotmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Donald C Bolser
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Peter Machac
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Jan Jakus
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
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Jaster JH. Medicine in the future - with subspecialists in medullary neurology and brain dentistry. World J Neurol 2015; 5:107-112. [DOI: 10.5316/wjn.v5.i4.107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/19/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
The solitary tract nucleus of the medulla with its limited watershed vascular capacity may occasionally be the focus of transient ischemia caused by the increased metabolic demands associated with frequent and intense neuronal stimulation from other organs and other parts of the brain. Case reports have suggested that these ischemic changes may sometimes result in the initiation of intense autonomic discharges, which can occasionally be fatal. Therapeutic interventions for the medulla oblongata are hampered by its limited accessibility. Systemically administered pharmaceuticals may have some usefulness in future years. Previous experience with vagus nerve stimulation in the treatment of epilepsy suggests that it may have some usefulness in stabilizing medullary autonomic discharges. Computerized electronic stimulation of other cranial nerves may be helpful as well, especially the chorda tympani nerve, and may be most easily accomplished from implanted dental appliances, especially molar modules, transmitting signals via secondary transmitters procedurally placed on cranial nerves. Future technology may enable wireless signaling from the implanted dental appliance to the secondary transmitter placed at the nerve site. By the year 2050 subspecialists in medullary neurology and brain dentistry may use computerized electronic stimulation of cranial nerves to prevent sudden unexpected death and treat “chest pain from the brain”.
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Gekka M, Yamaguchi S, Kazumata K, Kobayashi H, Motegi H, Terasaka S, Houkin K. Hemorrhagic onset of hemangioblastoma located in the dorsal medulla oblongata presenting with tako-tsubo cardiomyopathy and neurogenic pulmonary edema: a case report. Case Rep Neurol 2014; 6:68-73. [PMID: 24803905 PMCID: PMC4000297 DOI: 10.1159/000361041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Here, we present a case of dorsal medulla oblongata hemangioblastoma with fourth ventricular hemorrhage. A 23-year-old female developed sudden consciousness disturbance, and CT revealed hemorrhage in all cerebral ventricles and a hyperdense mass in the cisterna magna. Although the reddish tumor located in the dorsal medulla oblongata was successfully removed, she suffered from severe tako-tsubo cardiomyopathy (TTC) and neurogenic pulmonary edema (NPE) because of baroreflex failure and damage to the solitary tract nuclei. After intensive care for 12 weeks following surgery, she was discharged without any neurological or radiological deficits. Pathogenesis of TTC/NPE is discussed in this paper.
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Affiliation(s)
- Masayuki Gekka
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Shigeru Yamaguchi
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Ken Kazumata
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroyuki Kobayashi
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroaki Motegi
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Shunsuke Terasaka
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kiyohiro Houkin
- Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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