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Utricular dysfunction in patients with orthostatic hypotension. Clin Auton Res 2022; 32:431-444. [PMID: 36074194 DOI: 10.1007/s10286-022-00890-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 08/22/2022] [Indexed: 01/31/2023]
Abstract
PURPOSE To delineate the association between otolithic dysfunction and orthostatic hypotension (OH). METHODS We retrospectively reviewed the medical records of 382 patients who presented with orthostatic dizziness at a tertiary dizziness center between July 2017 and December 2021. Patients were included for analyses when they had completed ocular (oVEMP) and/or cervical vestibular-evoked myogenic potentials (cVEMP), and head-up tilt table test with a Finometer (n = 155). We compared the results between the patients with OH (n = 38) and those with NOI (normal head-up tilt table test despite orthostatic intolerance, n = 117). RESULTS Thirty-eight patients with OH were further categorized as either classic (n = 30), delayed (n = 7), or initial (n = 1) types. Multivariable logistic regression showed that OH was associated with high baseline systolic BP (p = 0.046), presence of heart failure (p = 0.016), and unilateral oVEMP abnormalities (p = 0.016). n1 latency of oVEMP were negatively correlated with the maximal changes of systolic blood pressure (BP) in 15 s ([Formula: see text]SBP15s, p = 0.013), 3 min ([Formula: see text]SBP3min, p = 0.005) and 10 min ([Formula: see text]SBP10min, p = 0.002). In contrast, the n1-p1 amplitude was positively correlated with [Formula: see text]SBP15s (p = 0.029). Meanwhile, p13 latency of cVEMP was negatively correlated with [Formula: see text]SBP10min (p = 0.018). CONCLUSIONS Our study provides evidence of utricular dysfunction related to OH.
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Rice D, Martinelli GP, Jiang W, Holstein GR, Rajguru SM. Pulsed Infrared Stimulation of Vertical Semicircular Canals Evokes Cardiovascular Changes in the Rat. Front Neurol 2021; 12:680044. [PMID: 34122320 PMCID: PMC8193737 DOI: 10.3389/fneur.2021.680044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022] Open
Abstract
A variety of stimuli activating vestibular end organs, including sinusoidal galvanic vestibular stimulation, whole body rotation and tilt, and head flexion have been shown to evoke significant changes in blood pressure (BP) and heart rate (HR). While a role for the vertical semicircular canals in altering autonomic activity has been hypothesized, studies to-date attribute the evoked BP and HR responses to the otolith organs. The present study determined whether unilateral activation of the posterior (PC) or anterior (AC) semicircular canal is sufficient to elicit changes in BP and/or HR. The study employed frequency-modulated pulsed infrared radiation (IR: 1,863 nm) directed via optical fibers to PC or AC of adult male Long-Evans rats. BP and HR changes were detected using a small-animal single pressure telemetry device implanted in the femoral artery. Eye movements evoked during IR of the vestibular endorgans were used to confirm the stimulation site. We found that sinusoidal IR delivered to either PC or AC elicited a rapid decrease in BP and HR followed by a stimulation frequency-matched modulation. The magnitude of the initial decrements in HR and BP did not correlate with the energy of the suprathreshold stimulus. This response pattern was consistent across multiple trials within an experimental session, replicable, and in most animals showed no evidence of habituation or an additive effect. Frequency modulated electrical current delivered to the PC and IR stimulation of the AC, caused decrements in HR and BP that resembled those evoked by IR of the PC. Frequency domain heart rate variability assessment revealed that, in most subjects, IR stimulation increased the low frequency (LF) component and decreased the high frequency (HF) component, resulting in an increase in the LF/HF ratio. This ratio estimates the relative contributions of sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) activities. An injection of atropine, a muscarinic cholinergic receptor antagonist, diminished the IR evoked changes in HR, while the non-selective beta blocker propranolol eliminated changes in both HR and BP. This study provides direct evidence that activation of a single vertical semicircular canal is sufficient to activate and modulate central pathways that control HR and BP.
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Affiliation(s)
- Darrian Rice
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Giorgio P Martinelli
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Weitao Jiang
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Gay R Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States.,Department of Otolaryngology, University of Miami, Miami, FL, United States
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3
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Direct comparison of activation maps during galvanic vestibular stimulation: A hybrid H2[15 O] PET-BOLD MRI activation study. PLoS One 2020; 15:e0233262. [PMID: 32413079 PMCID: PMC7228124 DOI: 10.1371/journal.pone.0233262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 05/01/2020] [Indexed: 12/17/2022] Open
Abstract
Previous unimodal PET and fMRI studies in humans revealed a reproducible vestibular brain activation pattern, but with variations in its weighting and expansiveness. Hybrid studies minimizing methodological variations at baseline conditions are rare and still lacking for task-based designs. Thus, we applied for the first time hybrid 3T PET-MRI scanning (Siemens mMR) in healthy volunteers using galvanic vestibular stimulation (GVS) in healthy volunteers in order to directly compare H215O-PET and BOLD MRI responses. List mode PET acquisition started with the injection of 750 MBq H215O simultaneously to MRI EPI sequences. Group-level statistical parametric maps were generated for GVS vs. rest contrasts of PET, MR-onset (event-related), and MR-block. All contrasts showed a similar bilateral vestibular activation pattern with remarkable proximity of activation foci. Both BOLD contrasts gave more bilateral wide-spread activation clusters than PET; no area showed contradictory signal responses. PET still confirmed the right-hemispheric lateralization of the vestibular system, whereas BOLD-onset revealed only a tendency. The reciprocal inhibitory visual-vestibular interaction concept was confirmed by PET signal decreases in primary and secondary visual cortices, and BOLD-block decreases in secondary visual areas. In conclusion, MRI activation maps contained a mixture of CBF measured using H215O-PET and additional non-CBF effects, and the activation-deactivation pattern of the BOLD-block appears to be more similar to the H215O-PET than the BOLD-onset.
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4
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Aghababaei Ziarati M, Taziki MH, Hosseini SM. Autonomic laterality in caloric vestibular stimulation. World J Cardiol 2020; 12:144-154. [PMID: 32431785 PMCID: PMC7215963 DOI: 10.4330/wjc.v12.i4.144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/12/2020] [Accepted: 03/26/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Caloric stimulation of the vestibular system is associated with autonomic response. The lateralization in the nervous system activities also involves the autonomic nervous system.
AIM To compare the effect of the right and left ear caloric test on the cardiac sympathovagal tone in healthy persons.
METHODS This self-control study was conducted on 12 healthy male volunteers. The minimal ice water caloric test was applied for vestibular stimulation. This was done by irrigating 1 milliliter of 4 ± 2 °C ice water into the external ear canal in 1 s. In each experiment, only one ear was stimulated. For each ear, the pessimum position was considered as sham control and the optimum position was set as caloric vestibular stimulation of horizontal semicircular channel. The order of right or left caloric vestibular stimulation and the sequence of optimum or pessimum head position in each set were random. The recovery time between each calorie test was 5 min. The short-term heart rate variability (HRV) was used for cardiac sympathovagal tone metrics. All variables were compared using the analysis of variance.
RESULTS After caloric vestibular stimulation, the short-term time-domain and frequency-domain HRV indices as well as, the systolic and the diastolic arterial blood pressure, the respiratory rate and the respiratory amplitude, had no significant changes. These negative results were similar in the right and the left sides. Nystagmus duration of left caloric vestibular stimulations in the optimum and the pessimum positions had significant differences (e.g., 72.14 ± 39.06 vs 45.35 ± 35.65, P < 0.01). Nystagmus duration of right caloric vestibular stimulations in the optimum and the pessimum positions had also significant differences (e.g., 86.42 ± 67.20 vs 50.71 ± 29.73, P < 0.01). The time of the start of the nystagmus following caloric vestibular stimulation had no differences in both sides and both positions.
CONCLUSION Minimal ice water caloric stimulation of the right and left vestibular system did not affect the cardiac sympathovagal balance according to HRV indices.
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Affiliation(s)
- Mohammadreza Aghababaei Ziarati
- Department of Internal Medicine, Medical Faculty, Golestan University of Medical Sciences, Gorgan 4934174515, Golestan, Iran
| | - Mohammad Hosein Taziki
- Department of Otolaryngology, Medical Faculty, Golestan University of Medical Sciences, Gorgan 4934174515, Golestan, Iran
| | - Seyed Mehran Hosseini
- Department of Physiology, Medical Faculty, Golestan University of Medical Sciences, Gorgan 4934174515, Golestan, Iran
- Neuroscience Research Center, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan 4934174515, Golestan, Iran
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5
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Morita H, Kaji H, Ueta Y, Abe C. Understanding vestibular-related physiological functions could provide clues on adapting to a new gravitational environment. J Physiol Sci 2020; 70:17. [PMID: 32169037 PMCID: PMC7069930 DOI: 10.1186/s12576-020-00744-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/03/2020] [Indexed: 12/16/2022]
Abstract
The peripheral vestibular organs are sensors for linear acceleration (gravity and head tilt) and rotation. Further, they regulate various body functions, including body stability, ocular movement, autonomic nerve activity, arterial pressure, body temperature, and muscle and bone metabolism. The gravitational environment influences these functions given the highly plastic responsiveness of the vestibular system. This review demonstrates that hypergravity or microgravity induces changes in vestibular-related physiological functions, including arterial pressure, muscle and bone metabolism, feeding behavior, and body temperature. Hopefully, this review contributes to understanding how human beings can adapt to a new gravitational environment, including the moon and Mars, in future.
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Affiliation(s)
- Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan.
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Faculty of Medicine, Kindai University, Osakasayama, 589-8511, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, 501-1194, Japan
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6
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Hammam E, Macefield VG. Vestibular Modulation of Sympathetic Nerve Activity to Muscle and Skin in Humans. Front Neurol 2017; 8:334. [PMID: 28798718 PMCID: PMC5526846 DOI: 10.3389/fneur.2017.00334] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/26/2017] [Indexed: 12/19/2022] Open
Abstract
We review the existence of vestibulosympathetic reflexes in humans. While several methods to activate the human vestibular apparatus have been used, galvanic vestibular stimulation (GVS) is a means of selectively modulating vestibular afferent activity via electrodes over the mastoid processes, causing robust vestibular illusions of side-to-side movement. Sinusoidal GVS (sGVS) causes partial entrainment of sympathetic outflow to muscle and skin. Modulation of muscle sympathetic nerve activity (MSNA) from vestibular inputs competes with baroreceptor inputs, with stronger temporal coupling to the vestibular stimulus being observed at frequencies remote from the cardiac frequency; “super entrainment” was observed in some individuals. Low-frequency (<0.2 Hz) sGVS revealed two peaks of modulation per cycle, with bilateral recordings of MSNA or skin sympathetic nerve activity, providing evidence of lateralization of sympathetic outflow during vestibular stimulation. However, it should be noted that GVS influences the firing of afferents from the entire vestibular apparatus, including the semicircular canals. To identify the specific source of vestibular input responsible for the generation of vestibulosympathetic reflexes, we used low-frequency (<0.2 Hz) sinusoidal linear acceleration of seated or supine subjects to, respectively, target the utricular or saccular components of the otoliths. While others had discounted the semicircular canals, we showed that the contributions of the utricle and saccule to the vestibular modulation of MSNA are very similar. Moreover, that modulation of MSNA occurs at accelerations well below levels at which subjects are able to perceive any motion indicates that, like vestibulospinal control of posture, the vestibular system contributes to the control of blood pressure through potent reflexes in humans.
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Affiliation(s)
- Elie Hammam
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
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Lu HJ, Li MH, Li MZ, Park SE, Kim MS, Jin YZ, Park BR. Functional Connections of the Vestibulo-spino-adrenal Axis in the Control of Blood Pressure Via the Vestibulosympathetic Reflex in Conscious Rats. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:427-34. [PMID: 26330755 PMCID: PMC4553402 DOI: 10.4196/kjpp.2015.19.5.427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/15/2015] [Accepted: 07/01/2015] [Indexed: 12/20/2022]
Abstract
Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements. In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation. Expression of c-Fos protein in the intermediolateral cell column of the middle thoracic spinal regions and blood epinephrine levels were investigated, following microinjection of glutamate receptor agonists or antagonists into the medial vestibular nucleus (MVN) and/or sodium nitroprusside (SNP)-induced hypotension. Both microinjection of glutamate receptor agonists (NMDA and AMPA) into the MVN or rostral ventrolateral medullary nucleus (RVLM) and SNP-induced hypotension led to increased number of c-Fos positive neurons in the intermediolateral cell column of the middle thoracic spinal regions and increased blood epinephrine levels. Pretreatment with microinjection of glutamate receptor antagonists (MK-801 and CNQX) into the MVN or RVLM prevented the increased number of c-Fos positive neurons resulting from SNP-induced hypotension, and reversed the increased blood epinephrine levels. These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.
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Affiliation(s)
- Huan-Jun Lu
- Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China
| | - Mei-Han Li
- Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China
| | - Mei-Zhi Li
- Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China
| | - Sang Eon Park
- Department of Physiology, Wonkwang University School of Medicine and Brain Science Institute at Wonkwang University, Iksan 570-749, Korea
| | - Min Sun Kim
- Department of Physiology, Wonkwang University School of Medicine and Brain Science Institute at Wonkwang University, Iksan 570-749, Korea
| | - Yuan-Zhe Jin
- Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China
| | - Byung Rim Park
- Department of Physiology, Wonkwang University School of Medicine and Brain Science Institute at Wonkwang University, Iksan 570-749, Korea
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Nalivaiko E, Rudd JA, So RH. Motion sickness, nausea and thermoregulation: The "toxic" hypothesis. Temperature (Austin) 2014; 1:164-71. [PMID: 27626043 PMCID: PMC5008705 DOI: 10.4161/23328940.2014.982047] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 10/23/2014] [Accepted: 10/27/2014] [Indexed: 11/19/2022] Open
Abstract
Principal symptoms of motion sickness in humans include facial pallor, nausea and vomiting, and sweating. It is less known that motion sickness also affects thermoregulation, and the purpose of this review is to present and discuss existing data related to this subject. Hypothermia during seasickness was firstly noted nearly 150 years ago, but detailed studies of this phenomenon were conducted only during the last 2 decades. Motion sickness-induced hypothermia is philogenetically quite broadly expressed as besides humans, it has been reported in rats, musk shrews and mice. Evidence from human and animal experiments indicates that the physiological mechanisms responsible for the motion sickness-induced hypothermia include cutaneous vasodilation and sweating (leading to an increase of heat loss) and reduced thermogenesis. Together, these results suggest that motion sickness triggers highly coordinated physiological response aiming to reduce body temperature. Finally, we describe potential adaptive role of this response, and describe the benefits of using it as an objective measure of motion sickness-induced nausea.
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Affiliation(s)
- Eugene Nalivaiko
- School of Biomedical Sciences and Pharmacy; University of Newcastle ; Callaghan, NSW, Australia
| | - John A Rudd
- School of Biomedical Sciences; Chinese University of Hong Kong, Shatin ; Hong Kong, China
| | - Richard Hy So
- Division of Biomedical Engineering; the Hong Kong University of Science and Technology ; Hong Kong, China
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9
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Grewal T, Dawood T, Hammam E, Kwok K, Macefield VG. Low-frequency physiological activation of the vestibular utricle causes biphasic modulation of skin sympathetic nerve activity in humans. Exp Brain Res 2012; 220:101-8. [PMID: 22623094 DOI: 10.1007/s00221-012-3118-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
Abstract
We have previously shown that sinusoidal galvanic vestibular stimulation, a means of selectively modulating vestibular afferent activity, can cause partial entrainment of sympathetic outflow to muscle and skin in human subjects. However, it influences the firing of afferents from the entire vestibular apparatus, including the semicircular canals. Here, we tested the hypothesis that selective stimulation of one set of otolithic organs-those located in the utricle, which are sensitive to displacement in the horizontal axis-could entrain sympathetic nerve activity. Skin sympathetic nerve activity (SSNA) was recorded via tungsten microelectrodes inserted into cutaneous fascicles of the common peroneal nerve in 10 awake subjects, seated (head vertical, eyes closed) on a motorised platform. Slow sinusoidal accelerations-decelerations (~4 mG) were applied in the X (antero-posterior) or Y (medio-lateral) direction at 0.08 Hz; composite movements in both directions were also applied. Subjects either reported feeling a vague sense of movement (with no sense of direction) or no movement at all. Nevertheless, cross-correlation analysis revealed a marked entrainment of SSNA for all types of movements: vestibular modulation was 97 ± 3 % for movements in the X axis and 91 ± 5 % for displacements in the Y axis. For each sinusoidal cycle, there were two major peaks of modulation-one associated with acceleration as the platform moved forward or to the side, and one associated with acceleration in the opposite direction. We interpret these observations as reflecting inertial displacement of the stereocilia within the utricle during acceleration, which causes a robust vestibulosympathetic reflex.
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Affiliation(s)
- Tarandeep Grewal
- School of Medicine, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
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10
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Carter JR, Ray CA. Sympathetic responses to vestibular activation in humans. Am J Physiol Regul Integr Comp Physiol 2008; 294:R681-8. [PMID: 18199586 DOI: 10.1152/ajpregu.00896.2007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Activation of sympathetic neural traffic via the vestibular system is referred to as the vestibulosympathetic reflex. Investigations of the vestibulosympathetic reflex in humans have been limited to the past decade, and the importance of this reflex in arterial blood pressure regulation is still being determined. This review provides a summary of sympathetic neural responses to various techniques used to engage the vestibulosympathetic reflex. Studies suggest that activation of the semicircular canals using caloric stimulation and yaw rotation do not modulate muscle sympathetic nerve activity (MSNA) or skin sympathetic nerve activity (SSNA). In contrast, activation of the otolith organs appear to alter MSNA, but not SSNA. Specifically, head-down rotation and off-vertical axis rotation increase MSNA, while sinusoidal linear accelerations decrease MSNA. Galvanic stimulation, which results in a nonspecific activation of the vestibule, appears to increase MSNA if the mode of delivery is pulse trained. In conclusion, evidence strongly supports the existence of a vestibulosympathetic reflex in humans. Furthermore, attenuation of the vestibulosympathetic reflex is coupled with a drop in arterial blood pressure in the elderly, suggesting this reflex may be important in human blood pressure regulation.
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Affiliation(s)
- Jason R Carter
- Department of Exercise, Health and Physical Education, Michigan Technological University, Houghton, Michigan, USA
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11
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Tanaka K, Gotoh TM, Awazu C, Morita H. Roles of the vestibular system in controlling arterial pressure in conscious rats during a short period of microgravity. Neurosci Lett 2006; 397:40-3. [PMID: 16384644 DOI: 10.1016/j.neulet.2005.11.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 11/27/2005] [Accepted: 11/28/2005] [Indexed: 11/27/2022]
Abstract
In order to evaluate the roles of the vestibular system in controlling arterial pressure (AP) during exposure to a short period of microgravity (microG), the AP was measured in conscious free-moving rats having intact vestibular systems and those having vestibular lesions (FM-Intact and FM-VL groups, respectively). During free drop-induced microG, the AP increased in the FM-Intact group; it was 38+/-4 mmHg more than the AP observed during 1G. However, the increase in AP was significantly lower in the FM-VL group (20+/-2 mmHg). Further, to examine the sudden effect of a body floating in the midair in response to the AP during exposure to muG a body stabilizer was placed on the back of rats having intact vestibular systems and those having vestibular lesions (STAB-Intact and STAB-VL groups, respectively). The increase in the AP was significantly depressed in the STAB-Intact group; when compared with that in the FM-Intact group, but the increase was still significant (27+/-2 mmHg). On the other hand, the increase in the AP was completely eliminated in the STAB-VL group (7+/-5 mmHg). These results indicate that the AP increases during exposure to muG in conscious rats, and the vestibular system and body stability are significantly involved in this response.
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Affiliation(s)
- Kunihiko Tanaka
- Department of Physiology, Gifu University, Graduate School of Medicine, Gifu 501-1194, Japan.
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Karasuno H, Morozumi K, Fujiwara T, Goh AC, Yamamoto I, Senga F. Changes in Intramuscular Blood Volume Induced by Continuous Shortwave Diathermy. J Phys Ther Sci 2005. [DOI: 10.1589/jpts.17.71] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Hiroshi Karasuno
- Research Institution of Health Science and Education
- Ito Co., Ltd
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13
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Mori RL, Cotter LA, Arendt HE, Olsheski CJ, Yates BJ. Effects of bilateral vestibular nucleus lesions on cardiovascular regulation in conscious cats. J Appl Physiol (1985) 2004; 98:526-33. [PMID: 15475594 DOI: 10.1152/japplphysiol.00970.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vestibular system participates in cardiovascular regulation during postural changes. In prior studies (Holmes MJ, Cotter LA, Arendt HE, Cas SP, and Yates BJ. Brain Res 938: 62-72, 2002, and Jian BJ, Cotter LA, Emanuel BA, Cass SP, and Yates BJ. J Appl Physiol 86: 1552-1560, 1999), transection of the vestibular nerves resulted in instability in blood pressure during nose-up body tilts, particularly when no visual information reflecting body position in space was available. However, recovery of orthostatic tolerance occurred within 1 wk, presumably because the vestibular nuclei integrate a variety of sensory inputs reflecting body location. The present study tested the hypothesis that lesions of the vestibular nuclei result in persistent cardiovascular deficits during orthostatic challenges. Blood pressure and heart rate were monitored in five conscious cats during nose-up tilts of varying amplitude, both before and after chemical lesions of the vestibular nuclei. Before lesions, blood pressure remained relatively stable during tilts. In all animals, the blood pressure responses to nose-up tilts were altered by damage to the medial and inferior vestibular nuclei; these effects were noted both when animals were tested in the presence and absence of visual feedback. In four of the five animals, the lesions also resulted in augmented heart rate increases from baseline values during 60 degrees nose-up tilts. These effects persisted for longer than 1 wk, but they gradually resolved over time, except in the animal with the worst deficits. These observations suggest that recovery of compensatory cardiovascular responses after loss of vestibular inputs is accomplished at least in part through plastic changes in the vestibular nuclei and the enhancement of the ability of vestibular nucleus neurons to discriminate body position in space by employing nonlabyrinthine signals.
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Affiliation(s)
- R L Mori
- Univ. of Pittsburgh, School of Medicine, Dept. of Otolaryngology, Rm. 519, Pittsburgh, PA 15213, USA
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14
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Wilson TE, Kuipers NT, McHugh EA, Ray CA. Vestibular activation does not influence skin sympathetic nerve responses during whole body heating. J Appl Physiol (1985) 2004; 97:540-4. [PMID: 15075298 DOI: 10.1152/japplphysiol.00174.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cutaneous vasculature and eccrine sweat glands are modified by both thermal and nonthermal factors. To determine the effect of thermal stress on the vestibulosympathetic reflex, skin sympathetic nerve activity (SSNA) and cutaneous end-organ responses were measured in 10 subjects during static head-down rotation (HDR) and dynamic yaw and pitch (30 cycles/min) to activate the otolith organs and semicircular canals. SSNA (microneurography of peroneal nerve), cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial pressure), sweat rate (capacitance hygrometry), and body temperature were collected during normothermia and after whole body heating. Body temperature was controlled by perfusing neutral (34-35 degrees C) or warm (44-46 degrees C) water through a tube-lined suit. During normothermia, HDR did not alter SSNA (-0.4 +/- 4.4% change), CVC (4.2 +/- 6.9% change), or sweat rate (-2.7 +/- 1.2% change) within the innervated area of skin. Dynamic yaw and pitch also did not elicit significant changes in SSNA, CVC, or sweat rate during normothermia. Whole body heating significantly increased internal temperature (0.8 +/- 0.1 degrees C), mean skin temperature (4.1 +/- 0.2 degrees C), CVC (322 +/- 109% control), and sweat rate (0.35 +/- 0.08 mg.cm(-2).min(-1)). After whole body heating, HDR did not significantly alter SSNA (3.2 +/- 7.6% change), CVC (-7.3 +/- 3.9% change), or sweat rate (-3.3 +/- 1.9% change). Dynamic yaw and pitch also did not produce significant changes in SSNA, CVC, or sweat rate after whole body heating. These data suggest that vestibular activation by head movements is not a nonthermal factor affecting SSNA and cutaneous end-organ responses in humans.
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Affiliation(s)
- Thad E Wilson
- Division of Cardiology, Department of Medicine, Pennsylvania State College of Medicine, H047, 500 University Dr., Hershey, PA 17033-2390, USA
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Gotoh TM, Fujiki N, Matsuda T, Gao S, Morita H. Roles of baroreflex and vestibulosympathetic reflex in controlling arterial blood pressure during gravitational stress in conscious rats. Am J Physiol Regul Integr Comp Physiol 2003; 286:R25-30. [PMID: 14500268 DOI: 10.1152/ajpregu.00458.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gravity acts on the circulatory system to decrease arterial blood pressure (AP) by causing blood redistribution and reduced venous return. To evaluate roles of the baroreflex and vestibulosympathetic reflex (VSR) in maintaining AP during gravitational stress, we measured AP, heart rate (HR), and renal sympathetic nerve activity (RSNA) in four groups of conscious rats, which were either intact or had vestibular lesions (VL), sinoaortic denervation (SAD), or VL plus SAD (VL + SAD). The rats were exposed to 3 G in dorsoventral axis by centrifugation for 3 min. In rats in which neither reflex was functional (VL + SAD group), RSNA did not change, but the AP showed a significant decrease (-8 +/- 1 mmHg vs. baseline). In rats with a functional baroreflex, but no VSR (VL group), the AP did not change and there was a slight increase in RSNA (25 +/- 10% vs. baseline). In rats with a functional VSR, but no baroreflex (SAD group), marked increases in both AP and RSNA were observed (AP 31 +/- 6 mmHg and RSNA 87 +/- 10% vs. baseline), showing that the VSR causes an increase in AP in response to gravitational stress; these marked increases were significantly attenuated by the baroreflex in the intact group (AP 9 +/- 2 mmHg and RSNA 38 +/- 7% vs. baseline). In conclusion, AP is controlled by the combination of the baroreflex and VSR. The VSR elicits a huge pressor response during gravitational stress, preventing hypotension due to blood redistribution. In intact rats, this AP increase is compensated by the baroreflex, resulting in only a slight increase in AP.
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Affiliation(s)
- Taro Miyahara Gotoh
- Department of Physiology, Gifu University School of Medicine, 40 Tsukasa-Machi, Gifu 500-8705, Japan.
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Mekjavic IB, Tipton MJ, Gennser M, Eiken O. Motion sickness potentiates core cooling during immersion in humans. J Physiol 2001; 535:619-23. [PMID: 11533150 PMCID: PMC2278781 DOI: 10.1111/j.1469-7793.2001.00619.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
1. The present study tested the hypothesis that motion sickness affects thermoregulatory responses to cooling in humans. 2. Ten healthy male volunteers underwent three separate head-out immersions in 28 degrees C water after different preparatory procedures. In the 'control' procedure immersion was preceded by a rest period. In the 'motion sickness' procedure immersion was preceded by provocation of motion sickness in a human centrifuge. This comprised rapid and repeated alterations of the gravitational (G-) stress in the head-to-foot direction, plus a standardized regimen of head movements at increased G-stress. In the 'G-control' procedure, the subjects were exposed to similar G-stress, but without the motion sickness provocation. 3. During immersion mean skin temperature, rectal temperature, the difference in temperature between the forearm and 3rd digit of the right hand (DeltaT(forearm-fingertip)), oxygen uptake and heart rate were recorded. Subjects provided ratings of temperature perception, thermal comfort and level of motion sickness discomfort at regular intervals. 4. No differences were observed in any of the variables between control and G-control procedures. In the motion sickness procedure, the DeltaT(forearm-fingertip) response was significantly attenuated, indicating a blunted vasoconstrictor response, and rectal temperature decreased at a faster rate. No other differences were observed. 5. Motion sickness attenuates the vasoconstrictor response to skin and core cooling, thereby enhancing heat loss and the magnitude of the fall in deep body temperature. Motion sickness may predispose individuals to hypothermia, and have significant implications for survival time in maritime accidents.
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Affiliation(s)
- I B Mekjavic
- Institute of Biomedical & Biomolecular Sciences, Department of Sports and Exercise Science, University of Portsmouth, Portsmouth, Hampshire PO1 2DT, UK.
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Cui J, Iwase S, Mano T, Katayama N, Mori S. Muscle sympathetic outflow during horizontal linear acceleration in humans. Am J Physiol Regul Integr Comp Physiol 2001; 281:R625-34. [PMID: 11448868 DOI: 10.1152/ajpregu.2001.281.2.r625] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To elucidate the effects of linear acceleration on muscle sympathetic nerve activity (MSNA) in humans, 16 healthy men were tested in a linear accelerator. Measurements of MSNA, electrocardiogram, blood pressure, and thoracic impedance were undertaken during linear acceleration. Sinusoidal linear acceleration with peak values at +/-0.10, +/-0.15, and +/-0.20 G was applied in anteroposterior (+/-G(x), n = 10) or lateral (+/-G(y), n = 6) directions. The total activity and burst rate of MSNA decreased significantly during forward, backward, left, or right linear accelerations. The total activity of MSNA decreased to 50.5 +/- 6.9, 52.5 +/- 4.4, 71.2 +/- 9.6, and 67.6 +/- 8.2% from the baselines (100%) during linear accelerations with peak values at +/-0.20 G in the four directions, respectively. These results suggest that dynamic stimulation of otolith organs in horizontal directions in humans might inhibit MSNA directly in order to quickly redistribute blood to muscles during postural reflexes induced by passive movement, which supports the concept that the vestibular system contributes to sympathetic regulation in humans.
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Affiliation(s)
- J Cui
- Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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