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Thurston TS, Weavil JC, Georgescu VP, Wan HY, Birgenheier NM, Morrissey CK, Jessop JE, Amann M. The exercise pressor reflex - a pressure-raising mechanism with a limited role in regulating leg perfusion during locomotion in young healthy men. J Physiol 2023; 601:4557-4572. [PMID: 37698303 PMCID: PMC10592099 DOI: 10.1113/jp284870] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/15/2023] [Indexed: 09/13/2023] Open
Abstract
We investigated the role of the exercise pressor reflex (EPR) in regulating the haemodynamic response to locomotor exercise. Eight healthy participants (23 ± 3 years,V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ : 49 ± 6 ml/kg/min) performed constant-load cycling exercise (∼36/43/52/98%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ; 4 min each) without (CTRL) and with (FENT) lumbar intrathecal fentanyl attenuating group III/IV locomotor muscle afferent feedback and, thus, the EPR. To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during FENT, subjects mimicked the ventilatory response recorded during CTRL. Arterial and leg perfusion pressure (femoral arterial and venous catheters), femoral blood flow (Doppler-ultrasound), microvascular quadriceps blood flow index (indocyanine green), cardiac output (inert gas breathing), and systemic and leg vascular conductance were quantified during exercise. There were no cardiovascular and ventilatory differences between conditions at rest. Pulmonary ventilation, arterial blood gases and oxyhaemoglobin saturation were not different during exercise. Furthermore, cardiac output (-2% to -12%), arterial pressure (-7% to -15%) and leg perfusion pressure (-8% to -22%) were lower, and systemic (up to 16%) and leg (up to 27%) vascular conductance were higher during FENT compared to CTRL. Leg blood flow, microvascular quadriceps blood flow index, and leg O2 -transport and utilization were not different between conditions (P > 0.5). These findings reflect a critical role of the EPR in the autonomic control of the heart, vasculature and, ultimately, arterial pressure during locomotor exercise. However, the lack of a net effect of the EPR on leg blood flow challenges the idea of this cardiovascular reflex as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals. KEY POINTS: The role of the exercise pressor reflex (EPR) in regulating leg O2 -transport during human locomotion remains uncertain. We investigated the influence of the EPR on the cardiovascular response to cycling exercise. Lumbar intrathecal fentanyl was used to block group III/IV leg muscle afferents and debilitate the EPR at intensities ranging from 30% to 100%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ . To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during exercise with blocked leg muscle afferents, subjects mimicked the ventilatory response recorded during control exercise. Afferent blockade increased leg and systemic vascular conductance, but reduced cardiac output and arterial-pressure, with no net effect on leg blood flow. The EPR influenced the cardiovascular response to cycling exercise by contributing to the autonomic control of the heart and vasculature, but did not affect leg blood flow. These findings challenge the idea of the EPR as a key determinant of leg O2 -transport during locomotor exercise in healthy, young individuals.
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Affiliation(s)
- Taylor S. Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Joshua C. Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT
| | - Vincent P. Georgescu
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
| | - Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | | | | | - Jacob E. Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT
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2
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Tadler SC, Jones KG, Lybbert C, Huang JC, Jawish R, Solzbacher D, Kendrick EJ, Pierson MD, Weischedel K, Rana N, Jacobs R, Vonesh LC, Feldman DA, Larson C, Hoffman N, Jessop JE, Larson AL, Taylor NE, Odell DH, Kuck K, Mickey BJ. Propofol for treatment resistant depression: A randomized controlled trial. medRxiv 2023:2023.09.12.23294678. [PMID: 37745479 PMCID: PMC10516089 DOI: 10.1101/2023.09.12.23294678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Background Anesthetic agents including ketamine and nitrous oxide have shown antidepressant properties when appropriately dosed. Our recent open-label trial of propofol, an intravenous anesthetic known to elicit transient positive mood effects, suggested that it may also produce robust and durable antidepressant effects when administered at a high dose that elicits an electroencephalographic (EEG) burst-suppression state. Here we report findings from a randomized controlled trial ( NCT03684447 ) that compared two doses of propofol. We hypothesized greater improvement with a high dose that evoked burst suppression versus a low dose that did not. Methods Participants with moderate-to-severe, treatment-resistant depression were randomized to a series of 6 treatments at low versus high dose (n=12 per group). Propofol infusions were guided by real-time processed frontal EEG to achieve predetermined pharmacodynamic criteria. The primary and secondary depression outcome measures were the 24-item Hamilton Depression Rating Scale (HDRS-24) and the Patient Health Questionnaire (PHQ-9), respectively. Secondary scales measured suicidal ideation, anxiety, functional impairment, and quality of life. Results Treatments were well tolerated and blinding procedures were effective. The mean [95%-CI] change in HDRS-24 score was -5.3 [-10.3, -0.2] for the low-dose group and -9.3 [-12.9, -5.6] for the high-dose group (17% versus 33% reduction). The between-group effect size (standardized mean difference) was -0.56 [-1.39, 0.28]. The group difference was not statistically significant (p=0.24, linear model). The mean change in PHQ-9 score was -2.0 [-3.9, -0.1] for the low dose and -4.8 [-7.7, -2.0] for the high dose. The between-group effect size was -0.73 [-1.59, 0.14] (p=0.09). Secondary outcomes favored the high dose (effect sizes magnitudes 0.1 - 0.9) but did not generally reach statistical significance (p>0.05). Conclusions The medium-sized effects observed between doses in this small, controlled, clinical trial suggest that propofol may have dose-dependent antidepressant effects. The findings also provide guidance for subsequent trials. A larger sample size and additional treatments in series are likely to enhance the ability to detect dose-dependent effects. Future work is warranted to investigate potential antidepressant mechanisms and dose optimization.
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Jones KG, Lybbert C, Euler MJ, Huang J, Lunt S, Richards SV, Jessop JE, Larson A, Odell DH, Kuck K, Tadler SC, Mickey BJ. Diversity of electroencephalographic patterns during propofol-induced burst suppression. Front Syst Neurosci 2023; 17:1172856. [PMID: 37397237 PMCID: PMC10309040 DOI: 10.3389/fnsys.2023.1172856] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/23/2023] [Indexed: 07/04/2023] Open
Abstract
Burst suppression is a brain state consisting of high-amplitude electrical activity alternating with periods of quieter suppression that can be brought about by disease or by certain anesthetics. Although burst suppression has been studied for decades, few studies have investigated the diverse manifestations of this state within and between human subjects. As part of a clinical trial examining the antidepressant effects of propofol, we gathered burst suppression electroencephalographic (EEG) data from 114 propofol infusions across 21 human subjects with treatment-resistant depression. This data was examined with the objective of describing and quantifying electrical signal diversity. We observed three types of EEG burst activity: canonical broadband bursts (as frequently described in the literature), spindles (narrow-band oscillations reminiscent of sleep spindles), and a new feature that we call low-frequency bursts (LFBs), which are brief deflections of mainly sub-3-Hz power. These three features were distinct in both the time and frequency domains and their occurrence differed significantly across subjects, with some subjects showing many LFBs or spindles and others showing very few. Spectral-power makeup of each feature was also significantly different across subjects. In a subset of nine participants with high-density EEG recordings, we noted that each feature had a unique spatial pattern of amplitude and polarity when measured across the scalp. Finally, we observed that the Bispectral Index Monitor, a commonly used clinical EEG monitor, does not account for the diversity of EEG features when processing the burst suppression state. Overall, this study describes and quantifies variation in the burst suppression EEG state across subjects and repeated infusions of propofol. These findings have implications for the understanding of brain activity under anesthesia and for individualized dosing of anesthetic drugs.
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Affiliation(s)
- Keith G. Jones
- Interdepartmental Program in Neuroscience, The University of Utah, Salt Lake City, UT, United States
- Department of Psychiatry, Huntsman Mental Health Institute, The University of Utah, Salt Lake City, UT, United States
| | - Carter Lybbert
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - Matthew J. Euler
- Department of Psychology, The University of Utah, Salt Lake City, UT, United States
| | - Jason Huang
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
| | - Seth Lunt
- Department of Psychiatry, Huntsman Mental Health Institute, The University of Utah, Salt Lake City, UT, United States
| | - Sindhu V. Richards
- Department of Neurology, The University of Utah, Salt Lake City, UT, United States
| | - Jacob E. Jessop
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - Adam Larson
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - David H. Odell
- Department of Psychiatry, Huntsman Mental Health Institute, The University of Utah, Salt Lake City, UT, United States
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - Kai Kuck
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - Scott C. Tadler
- Department of Psychiatry, Huntsman Mental Health Institute, The University of Utah, Salt Lake City, UT, United States
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
| | - Brian J. Mickey
- Interdepartmental Program in Neuroscience, The University of Utah, Salt Lake City, UT, United States
- Department of Psychiatry, Huntsman Mental Health Institute, The University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
- Department of Anesthesiology, The University of Utah, Salt Lake City, UT, United States
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4
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Lewis MT, Blain GM, Hart CR, Layec G, Rossman MJ, Park SY, Trinity JD, Gifford JR, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Amann M, Richardson RS. Acute high-intensity exercise and skeletal muscle mitochondrial respiratory function: role of metabolic perturbation. Am J Physiol Regul Integr Comp Physiol 2021; 321:R687-R698. [PMID: 34549627 DOI: 10.1152/ajpregu.00158.2021] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recently it was documented that fatiguing, high-intensity exercise resulted in a significant attenuation in maximal skeletal muscle mitochondrial respiratory capacity, potentially due to the intramuscular metabolic perturbation elicited by such intense exercise. With the utilization of intrathecal fentanyl to attenuate afferent feedback from group III/IV muscle afferents, permitting increased muscle activation and greater intramuscular metabolic disturbance, this study aimed to better elucidate the role of metabolic perturbation on mitochondrial respiratory function. Eight young, healthy males performed high-intensity cycle exercise in control (CTRL) and fentanyl-treated (FENT) conditions. Liquid chromatography-mass spectrometry and high-resolution respirometry were used to assess metabolites and mitochondrial respiratory function, respectively, pre- and postexercise in muscle biopsies from the vastus lateralis. Compared with CTRL, FENT yielded a significantly greater exercise-induced metabolic perturbation (PCr: -67% vs. -82%, Pi: 353% vs. 534%, pH: -0.22 vs. -0.31, lactate: 820% vs. 1,160%). Somewhat surprisingly, despite this greater metabolic perturbation in FENT compared with CTRL, with the only exception of respiratory control ratio (RCR) (-3% and -36%) for which the impact of FENT was significantly greater, the degree of attenuated mitochondrial respiratory capacity postexercise was not different between CTRL and FENT, respectively, as assessed by maximal respiratory flux through complex I (-15% and -33%), complex II (-36% and -23%), complex I + II (-31% and -20%), and state 3CI+CII control ratio (-24% and -39%). Although a basement effect cannot be ruled out, this failure of an augmented metabolic perturbation to extensively further attenuate mitochondrial function questions the direct role of high-intensity exercise-induced metabolite accumulation in this postexercise response.
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Affiliation(s)
- Matthew T Lewis
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Gregory M Blain
- LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Corey R Hart
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Gwenael Layec
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Matthew J Rossman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Song-Young Park
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,School of Health and Kinesiology, University of Nebraska, Omaha, Nebraska
| | - Joel D Trinity
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Simranjit K Sidhu
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Thomas J Hureau
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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5
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Trinity JD, Kwon OS, Broxterman RM, Gifford JR, Kithas AC, Hydren JR, Jarrett CL, Shields KL, Bisconti AV, Park SH, Craig JC, Nelson AD, Morgan DE, Jessop JE, Bledsoe AD, Richardson RS. The role of the endothelium in the hyperemic response to passive leg movement: looking beyond nitric oxide. Am J Physiol Heart Circ Physiol 2020; 320:H668-H678. [PMID: 33306447 DOI: 10.1152/ajpheart.00784.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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] [Indexed: 01/03/2023]
Abstract
Passive leg movement (PLM) evokes a robust and predominantly nitric oxide (NO)-mediated increase in blood flow that declines with age and disease. Consequently, PLM is becoming increasingly accepted as a sensitive assessment of endothelium-mediated vascular function. However, a substantial PLM-induced hyperemic response is still evoked despite nitric oxide synthase (NOS) inhibition. Therefore, in nine young healthy men (25 ± 4 yr), this investigation aimed to determine whether the combination of two potent endothelium-dependent vasodilators, specifically prostaglandin (PG) and endothelium-derived hyperpolarizing factor (EDHF), account for the remaining hyperemic response to the two variants of PLM, PLM (60 movements) and single PLM (sPLM, 1 movement), when NOS is inhibited. The leg blood flow (LBF, Doppler ultrasound) response to PLM and sPLM following the intra-arterial infusion of NG-monomethyl-l-arginine (l-NMMA), to inhibit NOS, was compared to the combined inhibition of NOS, cyclooxygenase (COX), and cytochrome P-450 (CYP450) by l-NMMA, ketorolac tromethamine (KET), and fluconazole (FLUC), respectively. NOS inhibition attenuated the overall LBF [area under the curve (LBFAUC)] response to both PLM (control: 456 ± 194, l-NMMA: 168 ± 127 mL, P < 0.01) and sPLM (control: 185 ± 171, l-NMMA: 62 ± 31 mL, P = 0.03). The combined inhibition of NOS, COX, and CYP450 (i.e., l-NMMA+KET+FLUC) did not further attenuate the hyperemic responses to PLM (LBFAUC: 271 ± 97 mL, P > 0.05) or sPLM (LBFAUC: 72 ± 45 mL, P > 0.05). Therefore, PG and EDHF do not collectively contribute to the non-NOS-derived NO-mediated, endothelium-dependent hyperemic response to either PLM or sPLM in healthy young men. These findings add to the mounting evidence and understanding of the vasodilatory pathways assessed by the PLM and sPLM vascular function tests.NEW & NOTEWORTHY Passive leg movement (PLM) evokes a highly nitric oxide (NO)-mediated hyperemic response and may provide a novel evaluation of vascular function. The contributions of endothelium-dependent vasodilatory pathways, beyond NO and including prostaglandins and endothelium-derived hyperpolarizing factor, to the PLM-induced hyperemic response to PLM have not been evaluated. With intra-arterial drug infusion, the combined inhibition of nitric oxide synthase (NOS), cyclooxygenase, and cytochrome P-450 (CYP450) pathways did not further diminish the hyperemic response to PLM compared with NOS inhibition alone.
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Affiliation(s)
- Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Oh Sung Kwon
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise Science, Brigham Young University, Provo, Utah
| | - Andrew C Kithas
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jay R Hydren
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Catherine L Jarrett
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Katherine L Shields
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Angela V Bisconti
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Soung Hun Park
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Jesse C Craig
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Ashley D Nelson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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6
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Kithas AC, Broxterman RM, Trinity JD, Gifford JR, Kwon OS, Hydren JR, Nelson AD, Jessop JE, Bledsoe AD, Morgan DE, Richardson RS. Nitric oxide synthase inhibition with N(G)-monomethyl-l-arginine: Determining the window of effect in the human vasculature. Nitric Oxide 2020; 104-105:51-60. [PMID: 32979497 DOI: 10.1016/j.niox.2020.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 07/20/2020] [Revised: 09/07/2020] [Accepted: 09/21/2020] [Indexed: 11/17/2022]
Abstract
Nitric oxide synthase (NOS) inhibition with N(G)-monomethyl-l-arginine (L-NMMA) is often used to assess the role of NO in human cardiovascular function. However, the window of effect for L-NMMA on human vascular function is unknown, which is critical for designing and interpreting human-based studies. This study utilized the passive leg movement (PLM) assessment of vascular function, which is predominantly NO-mediated, in 7 young male subjects under control conditions, immediately following intra-arterial L-NMMA infusion (0.24 mg⋅dl-1⋅min-1), and at 45-60 and 90-105 min post L-NMMA infusion. The leg blood flow (LBF) and leg vascular conductance (LVC) responses to PLM, measured with Doppler ultrasound and expressed as the change from baseline to peak (ΔLBFpeak and ΔLVCpeak) and area under the curve (LBFAUC and LVCACU), were assessed. PLM-induced robust control ΔLBFpeak (1135 ± 324 ml⋅min-1) and ΔLVCpeak (10.7 ± 3.6 ml⋅min-1⋅mmHg-1) responses that were significantly attenuated (704 ± 196 ml⋅min-1 and 6.7 ± 2 ml⋅min-1⋅mmHg-1) immediately following L-NMMA infusion. Likewise, control condition PLM ΔLBFAUC (455 ± 202 ml) and ΔLVCAUC (4.0 ± 1.4 ml⋅mmHg-1) were significantly attenuated (141 ± 130 ml and 1.3 ± 1.2 ml⋅mmHg-1) immediately following L-NMMA infusion. However, by 45-60 min post L-NMMA infusion all PLM variables were not significantly different from control, and this was still the case at 90-105 min post L-NMMA infusion. These findings reveal that the potent reduction in NO bioavailability afforded by NOS inhibition with L-NMMA has a window of effect of less than 45-60 min in the human vasculature. These data are particularly important for the commonly employed approach of pharmacologically inhibiting NOS with L-NMMA in the human vasculature.
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Affiliation(s)
- Andrew C Kithas
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Ryan M Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City, VAMC, UT, USA
| | - Joel D Trinity
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City, VAMC, UT, USA
| | - Jayson R Gifford
- Department of Exercise Sciences, Brigham Young University, Provo, UT, USA
| | - Oh Sung Kwon
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Jay R Hydren
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City, VAMC, UT, USA
| | - Ashley D Nelson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - David E Morgan
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City, VAMC, UT, USA.
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7
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Wan HY, Weavil JC, Thurston TS, Georgescu VP, Bledsoe AD, Jessop JE, Buys MJ, Richardson RS, Amann M. The muscle reflex and chemoreflex interaction: ventilatory implications for the exercising human. J Appl Physiol (1985) 2020; 129:691-700. [PMID: 32816637 DOI: 10.1152/japplphysiol.00449.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We examined the interactive influence of the muscle reflex (MR) and the chemoreflex (CR) on the ventilatory response to exercise. Eleven healthy subjects (5 women/6 men) completed three bouts of constant-load single-leg knee-extension exercise in a control trial and an identical trial conducted with lumbar intrathecal fentanyl to attenuate neural feedback from lower-limb group III/IV muscle afferents. The exercise during the two trials was performed while breathing ambient air ([Formula: see text] ~97%, [Formula: see text]~84 mmHg, [Formula: see text] ~32 mmHg, pH ~7.39), or under normocapnic hypoxia ([Formula: see text] ~79%, [Formula: see text] ~43 mmHg, [Formula: see text] ~33 mmHg, pH ~7.39) or normoxic hypercapnia ([Formula: see text] ~98%, [Formula: see text] ~105 mmHg, [Formula: see text] ~50 mmHg, pH ~7.26). During coactivation of the MR and the hypoxia-induced CR (O2-CR), minute ventilation (V̇e) and tidal volume (VT) were significantly greater compared with the sum of the responses to the activation of each reflex alone; there was no difference between the observed and summated responses in terms of breathing frequency (fB; P = 0.4). During coactivation of the MR and the hypercapnia-induced CR (CO2-CR), the observed ventilatory responses were similar to the summated responses of the reflexes (P ≥ 0.1). Therefore, the interaction between the MR and the O2-CR exerts a hyperadditive effect on V̇e and VT and an additive effect on fB, whereas the interaction between the MR and the CO2-CR is simply additive for all ventilatory parameters. These findings reveal that the MR:CR interaction further augments the ventilatory response to exercise in hypoxia.NEW & NOTEWORTHY Although the muscle reflex and the chemoreflex are recognized as independent feedback mechanisms regulating breathing during exercise, the ventilatory implications resulting from their interaction remain unclear. We quantified the individual and interactive effects of these reflexes during exercise and revealed differential modes of interaction. Importantly, the reflex interaction further amplifies the ventilatory response to exercise under hypoxemic conditions, highlighting a potential mechanism for optimizing arterial oxygenation in physically active humans at high altitude.
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Affiliation(s)
- Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Vincent P Georgescu
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Michael J Buys
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah
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8
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Wan HY, Weavil JC, Thurston TS, Georgescu VP, Hureau TJ, Bledsoe AD, Buys MJ, Jessop JE, Richardson RS, Amann M. The exercise pressor reflex and chemoreflex interaction: cardiovascular implications for the exercising human. J Physiol 2020; 598:2311-2321. [PMID: 32170732 DOI: 10.1113/jp279456] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [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: 12/17/2019] [Accepted: 03/10/2020] [Indexed: 01/11/2023] Open
Abstract
KEY POINTS Although the exercise pressor reflex (EPR) and the chemoreflex (CR) are recognized for their sympathoexcitatory effect, the cardiovascular implication of their interaction remains elusive. We quantified the individual and interactive cardiovascular consequences of these reflexes during exercise and revealed various modes of interaction. The EPR and hypoxia-induced CR interaction is hyper-additive for blood pressure and heart rate (responses during co-activation of the two reflexes are greater than the summation of the responses evoked by each reflex) and hypo-additive for peripheral haemodynamics (responses during co-activation of the reflexes are smaller than the summated responses). The EPR and hypercapnia-induced CR interaction results in a simple addition of the individual responses to each reflex (i.e. additive interaction). Collectively, EPR:CR co-activation results in significant cardiovascular interactions with restriction in peripheral haemodynamics, resulting from the EPR:CR interaction in hypoxia, likely having the most crucial impact on the functional capacity of an exercising human. ABSTRACT We investigated the interactive effect of the exercise pressor reflex (EPR) and the chemoreflex (CR) on the cardiovascular response to exercise. Eleven healthy participants (5 females) completed a total of six bouts of single-leg knee-extension exercise (60% peak work rate, 4 min each) either with or without lumbar intrathecal fentanyl to attenuate group III/IV afferent feedback from lower limbs to modify the EPR, while breathing either ambient air, normocapnic hypoxia (Sa O2 ∼79%, Pa O2 ∼43 mmHg, Pa CO2 ∼33 mmHg, pH ∼7.39), or normoxic hypercapnia (Sa O2 ∼98%, Pa O2 ∼105 mmHg, Pa CO2 ∼50 mmHg, pH ∼7.26) to modify the CR. During co-activation of the EPR and the hypoxia-induced CR (O2 -CR), mean arterial pressure and heart rate were significantly greater, whereas leg blood flow and leg vascular conductance were significantly lower than the summation of the responses evoked by each reflex alone. During co-activation of the EPR and the hypercapnia-induced CR (CO2 -CR), the haemodynamic responses were not different from the summated responses to each reflex response alone (P ≥ 0.1). Therefore, while the interaction resulting from the EPR:O2 -CR co-activation is hyper-additive for blood pressure and heart rate, and hypo-additive for peripheral haemodynamics, the interaction resulting from the EPR:CO2 -CR co-activation is simply additive for all cardiovascular parameters. Thus, EPR:CR co-activation results in significant interactions between cardiovascular reflexes, with the impact differing when the CR activation is achieved by hypoxia or hypercapnia. Since the EPR:CR co-activation with hypoxia potentiates the pressor response and restricts blood flow to contracting muscles, this interaction entails the most functional impact on an exercising human.
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Affiliation(s)
- Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City, UT, VAMC, USA
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Vincent P Georgescu
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Thomas J Hureau
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Michael J Buys
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Salt Lake City, UT, VAMC, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City, UT, VAMC, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
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9
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Thurston TS, Weavil JC, Georgescu VP, Broxterman RM, Wan HY, Birgenheier NM, Jessop JE, Morrissey CK, Richardson RS, Amann M. The Role of Group III/IV Muscle Afferents in Regulating the Hemodynamic Response to Whole Body Exercise. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Sidhu SK, Weavil JC, Rossman MJ, Jessop JE, Bledsoe AD, Buys MJ, Supiano MS, Richardson RS, Amann M. Exercise Pressor Reflex Contributes to the Cardiovascular Abnormalities Characterizing: Hypertensive Humans During Exercise. Hypertension 2019; 74:1468-1475. [PMID: 31607174 DOI: 10.1161/hypertensionaha.119.13366] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We investigated the impact of hypertension on circulatory responses to exercise and the role of the exercise pressor reflex in determining the cardiovascular abnormalities characterizing patients with hypertension. After a 7-day drug washout, 8 hypertensive (mean arterial pressure [MAP] 130±4 mm Hg; 65±3 years) and 8 normotensive (MAP 117±2 mm Hg; 65±2 years) individuals performed single-leg knee-extensor exercise (7 W, 15 W, 50%, 80%-Wpeak) under control conditions and with lumbar intrathecal fentanyl impairing feedback from µ-opioid receptor-sensitive leg muscle afferents. Femoral artery blood flow (QL), MAP (femoral artery), leg vascular conductance, and changes in cardiac output were continuously measured. While the increase in MAP from rest to control exercise was significantly greater in hypertension compared with normotension, the exercise-induced increase in cardiac output was comparable between groups, and QL and leg vascular conductance responses were ≈18% and ≈32% lower in the hypertensive patients (P<0.05). The blockade-induced decreases in MAP were significantly larger during exercise in hypertensive (≈11 mm Hg) compared with normotensive (≈6 mm Hg). Afferent blockade attenuated the central hemodynamic response to exercise similarly in both groups resulting in a ≈15% lower cardiac output at each workload. With no effect in normotensive, afferent blockade significantly raised the peripheral hemodynamic response to exercise in hypertensive, resulting in ≈14% and ≈23% higher QL and leg vascular conductance during exercise. Finally, QL and MAP during fentanyl-exercise in hypertensive were comparable to that of normotensive under control conditions (P>0.2). These findings suggest that exercise pressor reflex abnormalities largely account for the exaggerated MAP response and the impaired peripheral hemodynamics during exercise in hypertension.
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Affiliation(s)
- Simranjit K Sidhu
- From the Department of Internal Medicine, Division of Geriatrics (S.K.S., M.J.R., M.S.S., R.S.R., M.A.), University of Utah, Salt Lake City.,Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Australia (S.K.S.)
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, VAMC Salt Lake City, UT (J.C.W., M.S.S., R.S.R., M.A.)
| | - Matthew J Rossman
- From the Department of Internal Medicine, Division of Geriatrics (S.K.S., M.J.R., M.S.S., R.S.R., M.A.), University of Utah, Salt Lake City
| | - Jacob E Jessop
- Department of Anesthesiology (J.E.J., A.D.B., M.J.B., M.A.), University of Utah, Salt Lake City
| | - Amber D Bledsoe
- Department of Anesthesiology (J.E.J., A.D.B., M.J.B., M.A.), University of Utah, Salt Lake City
| | - Michael J Buys
- Department of Anesthesiology (J.E.J., A.D.B., M.J.B., M.A.), University of Utah, Salt Lake City
| | - Mark S Supiano
- From the Department of Internal Medicine, Division of Geriatrics (S.K.S., M.J.R., M.S.S., R.S.R., M.A.), University of Utah, Salt Lake City.,Geriatric Research, Education, and Clinical Center, VAMC Salt Lake City, UT (J.C.W., M.S.S., R.S.R., M.A.)
| | - Russell S Richardson
- From the Department of Internal Medicine, Division of Geriatrics (S.K.S., M.J.R., M.S.S., R.S.R., M.A.), University of Utah, Salt Lake City.,Geriatric Research, Education, and Clinical Center, VAMC Salt Lake City, UT (J.C.W., M.S.S., R.S.R., M.A.)
| | - Markus Amann
- From the Department of Internal Medicine, Division of Geriatrics (S.K.S., M.J.R., M.S.S., R.S.R., M.A.), University of Utah, Salt Lake City.,Department of Anesthesiology (J.E.J., A.D.B., M.J.B., M.A.), University of Utah, Salt Lake City.,Geriatric Research, Education, and Clinical Center, VAMC Salt Lake City, UT (J.C.W., M.S.S., R.S.R., M.A.)
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11
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Hureau TJ, Weavil JC, Thurston TS, Wan HY, Gifford JR, Jessop JE, Buys MJ, Richardson RS, Amann M. Pharmacological attenuation of group III/IV muscle afferents improves endurance performance when oxygen delivery to locomotor muscles is preserved. J Appl Physiol (1985) 2019; 127:1257-1266. [PMID: 31513446 DOI: 10.1152/japplphysiol.00490.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We sought to investigate the role of group III/IV muscle afferents in limiting endurance exercise performance, independently of their role in optimizing locomotor muscle O2 delivery. While breathing 100% O2 to ensure a similar arterial O2 content ([Formula: see text]) in both trials, eight male cyclists performed 5-km time trials under control conditions (HCTRL) and with lumbar intrathecal fentanyl (HFENT) impairing neural feedback from the lower limbs. After each time trial, common femoral artery blood flow (FBF) was quantified (Doppler ultrasound) during constant-load cycling performed at the average power of the preceding time trial. The assessment of end-tidal gases, hemoglobin content and saturation, and FBF facilitated the calculation of leg O2 delivery. Locomotor muscle activation during cycling was estimated from vastus lateralis EMG. With electrical femoral nerve stimulation, peripheral and central fatigue were quantified by pre- to postexercise decreases in quadriceps twitch torque (ΔQtw) and voluntary activation (ΔVA), respectively. FBF (~16 mL·min-1·W-1; P = 0.6), [Formula: see text] (~24 mL O2/dL; P = 0.9), and leg O2 delivery (~0.38 mL O2·min-1·W-1; P = 0.9) were not different during HCTRL and HFENT. Mean power output and time to completion were significantly improved by 9% (~310 W vs. ~288 W) and 3% (~479 s vs. ~463 s), respectively, during HFENT compared with HCTRL. Quadriceps muscle activation was 9 ± 7% higher during HFENT compared with HCTRL (P < 0.05). ΔQtw was significantly greater in HFENT compared with HCTRL (54 ± 8% vs. 39 ± 9%), whereas ΔVA was not different (~5%; P = 0.3) in both trials. These findings reveal that group III/IV muscle afferent feedback limits whole body endurance exercise performance and peripheral fatigue by restricting neural activation of locomotor muscle.NEW & NOTEWORTHY Group III/IV muscle afferent feedback facilitates endurance performance by optimizing locomotor muscle O2 delivery but also limits performance by restricting neural drive to locomotor muscle. To isolate the performance-limiting effect of these sensory neurons, we pharmacologically attenuated their central projection during a cycling time trial while controlling for locomotor muscle O2 delivery. With no difference in leg O2 delivery, afferent blockade attenuated the centrally mediated restriction in motoneuronal output and improved cycling performance.
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Affiliation(s)
- Thomas J Hureau
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Medicine and EA 3072: Mitochondria, Oxidative Stress and Muscular Protection Laboratory, University of Strasbourg, Strasbourg, France
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Hsuan-Yu Wan
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Michael J Buys
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Department of Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Anesthesiology, University of Utah, Salt Lake City, Utah
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12
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13
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Mickey BJ, White AT, Arp AM, Leonardi K, Torres MM, Larson AL, Odell DH, Whittingham SA, Beck MM, Jessop JE, Sakata DJ, Bushnell LA, Pierson MD, Solzbacher D, Kendrick EJ, Weeks HR, Light AR, Light KC, Tadler SC. Propofol for Treatment-Resistant Depression: A Pilot Study. Int J Neuropsychopharmacol 2018; 21:1079-1089. [PMID: 30260415 PMCID: PMC6276046 DOI: 10.1093/ijnp/pyy085] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/25/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND We hypothesized that propofol, a unique general anesthetic that engages N-methyl-D-aspartate and gamma-aminobutyric acid receptors, has antidepressant properties. This open-label trial was designed to collect preliminary data regarding the feasibility, tolerability, and efficacy of deep propofol anesthesia for treatment-resistant depression. METHODS Ten participants with moderate-to-severe medication-resistant depression (age 18-45 years and otherwise healthy) each received a series of 10 propofol infusions. Propofol was dosed to strongly suppress electroencephalographic activity for 15 minutes. The primary depression outcome was the 24-item Hamilton Depression Rating Scale. Self-rated depression scores were compared with a group of 20 patients who received electroconvulsive therapy. RESULTS Propofol treatments were well tolerated by all subjects. No serious adverse events occurred. Montreal Cognitive Assessment scores remained stable. Hamilton scores decreased by a mean of 20 points (range 0-45 points), corresponding to a mean 58% improvement from baseline (range 0-100%). Six of the 10 subjects met the criteria for response (>50% improvement). Self-rated depression improved similarly in the propofol group and electroconvulsive therapy group. Five of the 6 propofol responders remained well for at least 3 months. In posthoc analyses, electroencephalographic measures predicted clinical response to propofol. CONCLUSIONS These findings demonstrate that high-dose propofol treatment is feasible and well tolerated by individuals with treatment-resistant depression who are otherwise healthy. Propofol may trigger rapid, durable antidepressant effects similar to electroconvulsive therapy but with fewer side effects. Controlled studies are warranted to further evaluate propofol's antidepressant efficacy and mechanisms of action. ClinicalTrials.gov: NCT02935647.
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Affiliation(s)
- Brian J Mickey
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
- Department of Psychiatry, University of Michigan, Ann Arbor, MI
- Correspondence: Brian J. Mickey, MD, PhD, 501 Chipeta Way, Salt Lake City, Utah, 84108 ()
| | - Andrea T White
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Anna M Arp
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Kolby Leonardi
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Marina M Torres
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Adam L Larson
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - David H Odell
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | | | - Michael M Beck
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Derek J Sakata
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Lowry A Bushnell
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Matthew D Pierson
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Daniela Solzbacher
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - E Jeremy Kendrick
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
| | - Howard R Weeks
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Alan R Light
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Kathleen C Light
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
| | - Scott C Tadler
- Department of Psychiatry, University Neuropsychiatric Institute, University of Utah, Salt Lake City, UT
- Department of Anesthesiology, University of Utah, Salt Lake City, UT
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14
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Sidhu SK, Weavil JC, Thurston TS, Rosenberger D, Jessop JE, Wang E, Richardson RS, McNeil CJ, Amann M. Fatigue-related group III/IV muscle afferent feedback facilitates intracortical inhibition during locomotor exercise. J Physiol 2018; 596:4789-4801. [PMID: 30095164 DOI: 10.1113/jp276460] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [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: 05/09/2018] [Accepted: 07/25/2018] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS This study investigated the influence of group III/IV muscle afferents on corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. The study provides novel evidence to demonstrate that group III/IV muscle afferent feedback facilitates inhibitory intracortical neurons during whole body exercise. Firing of these interneurons probably contributes to the development of central fatigue during physical activity. ABSTRACT We investigated the influence of group III/IV muscle afferents in determining corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. Both under control conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from group III/IV leg muscle afferents, subjects (n = 11) cycled at a comparable vastus-lateralis EMG signal (∼0.26 mV) before (PRE; 100 W) and immediately after (POST; 90 ± 2 W) fatiguing constant-load cycling exercise (80% Wpeak; 221 ± 10 W; ∼8 min). During, PRE and POST cycling, single and paired-pulse (100 ms interstimulus interval) transcranial magnetic stimulations (TMS) were applied to elicit unconditioned and conditioned motor-evoked potentials (MEPs), respectively. To distinguish between cortical and spinal contributions to the MEPs, cervicomedullary stimulations (CMS) were used to elicit unconditioned (CMS only) and conditioned (TMS+CMS, 100 ms interval) cervicomedullary motor-evoked potentials (CMEPs). While unconditioned MEPs were unchanged from PRE to POST in CTRL, unconditioned CMEPs increased significantly, resulting in a decrease in unconditioned MEP/CMEP (P < 0.05). This paralleled a reduction in conditioned MEP (P < 0.05) and no change in conditioned CMEP. During FENT, unconditioned and conditioned MEPs and CMEPs were similar and comparable during PRE and POST (P > 0.2). These findings reveal that feedback from group III/IV muscle afferents innervating locomotor muscle decreases the excitability of the motor cortex during fatiguing cycling exercise. This impairment is, at least in part, determined by the facilitating effect of these sensory neurons on inhibitory GABAB intracortical interneurons.
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Affiliation(s)
- Simranjit K Sidhu
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Adelaide Medical School, Discipline of Physiology, The University of Adelaide, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | | | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Chris J McNeil
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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15
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Broxterman RM, Hureau TJ, Layec G, Morgan DE, Bledsoe AD, Jessop JE, Amann M, Richardson RS. Influence of group III/IV muscle afferents on small muscle mass exercise performance: a bioenergetics perspective. J Physiol 2018; 596:2301-2314. [PMID: 29644702 DOI: 10.1113/jp275817] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/28/2018] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS This investigation assessed the influence of group III/IV muscle afferents on small muscle mass exercise performance from a skeletal muscle bioenergetics perspective. Group III/IV muscle afferent feedback was attenuated with lumbar intrathecal fentanyl during intermittent isometric single-leg knee-extensor all-out exercise, while 31 P-MRS was used to assess skeletal muscle bioenergetics. Attenuation of group III/IV muscle afferent feedback improved exercise performance during the first minute of exercise, due to an increase in total ATP production with no change in the ATP cost of contraction. However, exercise performance was not altered during the remainder of the protocol, despite a sustained increase in total ATP production, due to an exacerbated ATP cost of contraction. These findings reveal that group III/IV muscle afferents directly limit exercise performance during small muscle mass exercise, but, due to their critical role in maintaining skeletal muscle contractile efficiency, with time, the benefit of attenuating the muscle afferents is negated. ABSTRACT The direct influence of group III/IV muscle afferents on exercise performance remains equivocal. Therefore, all-out intermittent isometric single-leg knee-extensor exercise and phosphorous magnetic resonance spectroscopy (31 P-MRS) were utilized to provide a high time resolution assessment of exercise performance and skeletal muscle bioenergetics in control conditions (CTRL) and with the attenuation of group III/IV muscle afferent feedback via lumbar intrathecal fentanyl (FENT). In both conditions, seven recreationally active men performed 60 maximal voluntary quadriceps contractions (MVC; 3 s contraction, 2 s relaxation), while knee-extensor force and 31 P-MRS were assessed during each MVC. The cumulative integrated force was significantly greater (8 ± 6%) in FENT than CTRL for the first minute of the all-out protocol, but was not significantly different for the second to fifth minutes. Total ATP production was significantly greater (16 ± 21%) in FENT than CTRL throughout the all-out exercise protocol, due to a significantly greater anaerobic ATP production (11 ± 13%) in FENT than CTRL with no significant difference in oxidative ATP production. The ATP cost of contraction was not significantly different between FENT and CTRL for the first minute of the all-out protocol, but was significantly greater (29 ± 34%) in FENT than in CTRL for the second to fifth minutes. These findings reveal that group III/IV muscle afferents directly limit exercise performance during small muscle mass exercise, but, due to their critical role in maintaining skeletal muscle contractile efficiency, with time, the benefit from muscle afferent attenuation is negated.
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Affiliation(s)
- Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Thomas J Hureau
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Gwenael Layec
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Center on Aging, University of Utah, Salt Lake City, UT, USA
| | - David E Morgan
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Markus Amann
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Center on Aging, University of Utah, Salt Lake City, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT, USA.,Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Center on Aging, University of Utah, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
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16
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Hureau TJ, Weavil JC, Thurston TS, Wan HY, Gifford JR, Jessop JE, Buys MJ, Richardson RS, Amann M. Muscle Afferent Blockade Improves Endurance Exercise Performance When O2 Transport To Locomotor Muscles Is Pre- served. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538796.56152.c9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Trinity JD, Broxterman RM, Gifford JR, Kwon OS, Hydren JR, Kithas AC, Nelson AD, Morgan DE, Jessop JE, Bledsoe A, Richardson RS. Mechanisms of Age‐related Compensatory Vasodilation: Insight from Passive Leg Movement. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.726.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joel D. Trinity
- Geriatric ResearchEducation and Clinical CenterSalt Lake City VAMCSalt Lake CityUT
- Nutrition and Integrative PhysiologyUniversity of UtahSaltUT
- Internal MedicinceUniversity of UtahSaltUT
| | - Ryan M. Broxterman
- Geriatric ResearchEducation and Clinical CenterSalt Lake City VAMCSalt Lake CityUT
| | - Jayson R. Gifford
- Geriatric ResearchEducation and Clinical CenterSalt Lake City VAMCSalt Lake CityUT
| | | | - Jay R. Hydren
- Nutrition and Integrative PhysiologyUniversity of UtahSaltUT
| | | | | | | | | | | | - Russell S. Richardson
- Geriatric ResearchEducation and Clinical CenterSalt Lake City VAMCSalt Lake CityUT
- Nutrition and Integrative PhysiologyUniversity of UtahSaltUT
- Internal MedicinceUniversity of UtahSaltUT
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Broxterman RM, Layec G, Hureau TJ, Morgan DE, Bledsoe AD, Jessop JE, Amann M, Richardson RS. Bioenergetics and ATP Synthesis during Exercise: Role of Group III/IV Muscle Afferents. Med Sci Sports Exerc 2018; 49:2404-2413. [PMID: 28767527 DOI: 10.1249/mss.0000000000001391] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The purpose of this study was to investigate the role of the group III/IV muscle afferents in the bioenergetics of exercising skeletal muscle beyond constraining the magnitude of metabolic perturbation. METHODS Eight healthy men performed intermittent isometric knee-extensor exercise to task failure at ~58% maximal voluntary contraction under control conditions (CTRL) and with lumbar intrathecal fentanyl to attenuate group III/IV leg muscle afferents (FENT). Intramuscular concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), diprotonated phosphate (H2PO4), adenosine triphosphate (ATP), and pH were determined using phosphorous magnetic resonance spectroscopy (P-MRS). RESULTS The magnitude of metabolic perturbation was significantly greater in FENT compared with CTRL for [Pi] (37.8 ± 16.8 vs 28.6 ± 8.6 mM), [H2PO4] (24.3 ± 12.2 vs 17.9 ± 7.1 mM), and [ATP] (75.8% ± 17.5% vs 81.9% ± 15.8% of baseline), whereas there was no significant difference in [PCr] (4.5 ± 2.4 vs 4.4 ± 2.3 mM) or pH (6.51 ± 0.10 vs 6.54 ± 0.14). The rate of perturbation in [PCr], [Pi], [H2PO4], and pH was significantly faster in FENT compared with CTRL. Oxidative ATP synthesis was not significantly different between conditions. However, anaerobic ATP synthesis, through augmented creatine kinase and glycolysis reactions, was significantly greater in FENT than in CTRL, resulting in a significantly greater ATP cost of contraction (0.049 ± 0.016 vs 0.038 ± 0.010 mM·min·N). CONCLUSION Group III/IV muscle afferents not only constrain the magnitude of perturbation in intramuscular Pi, H2PO4, and ATP during small muscle mass exercise but also seem to play a role in maintaining efficient skeletal muscle contractile function in men.
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Affiliation(s)
- Ryan M Broxterman
- 1Geriatric Research, Education, and Clinical Center, Salt Lake City Veteran's Affairs Medical Center, Salt Lake City, UT; 2Department of Internal Medicine, University of Utah, Salt Lake City, UT; 3Department of Anesthesiology, University of Utah, Salt Lake City, UT; and 4Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT
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19
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Hureau TJ, Weavil JC, Thurston TS, Broxterman RM, Nelson AD, Bledsoe AD, Jessop JE, Richardson RS, Wray DW, Amann M. Identifying the role of group III/IV muscle afferents in the carotid baroreflex control of mean arterial pressure and heart rate during exercise. J Physiol 2018; 596:1373-1384. [PMID: 29388218 DOI: 10.1113/jp275465] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [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: 10/23/2017] [Accepted: 01/29/2018] [Indexed: 02/05/2023] Open
Abstract
KEY POINTS We investigated the contribution of group III/IV muscle afferents to carotid baroreflex resetting during electrically evoked (no central command) and voluntary (requiring central command) isometric knee extension exercise. Lumbar intrathecal fentanyl was used to attenuate the central projection of μ-opioid receptor-sensitive group III/IV leg muscle afferent feedback. Spontaneous carotid baroreflex control was assessed by loading and unloading the carotid baroreceptors with a variable pressure neck chamber. Group III/IV muscle afferents did not influence spontaneous carotid baroreflex responsiveness at rest or during exercise. Afferent feedback accounted for at least 50% of the exercise-induced increase in the carotid baroreflex blood pressure and heart rate operating points, adjustments that are critical for an appropriate cardiovascular response to exercise. These findings suggest that group III/IV muscle afferent feedback is, independent of central command, critical for the resetting of the carotid baroreflex blood pressure and heart rate operating points, but not for spontaneous baroreflex responsiveness. ABSTRACT This study sought to comprehensively investigate the role of metabolically and mechanically sensitive group III/IV muscle afferents in carotid baroreflex responsiveness and resetting during both electrically evoked (EVO, no central command) and voluntary (VOL, requiring central command) isometric single-leg knee-extension (15% of maximal voluntary contraction; MVC) exercise. Participants (n = 8) were studied under control conditions (CTRL) and following lumbar intrathecal fentanyl injection (FENT) to inhibit μ-opioid receptor-sensitive lower limb muscle afferents. Spontaneous carotid baroreflex control of mean arterial pressure (MAP) and heart rate (HR) were assessed following rapid 5 s pulses of neck pressure (NP, +40 mmHg) or suction (NS, -60 mmHg). Resting MAP (87 ± 10 mmHg) and HR (70 ± 8 bpm) were similar between CTRL and FENT conditions (P > 0.4). In terms of spontaneous carotid baroreflex responsiveness, FENT did not alter the change in MAP or HR responses to NP (+13 ± 5 mmHg, P = 0.85; +9 ± 3 bpm; P = 0.99) or NS (-13 ± 5 mmHg, P = 0.99; -24 ± 11 bpm; P = 0.49) at rest or during either exercise protocol, which were of a remarkably similar magnitude to rest. In contrast, FENT administration reduced the exercise-induced resetting of the operating point for MAP and HR during both EVO (116 ± 10 mmHg to 100 ± 15 mmHg and 93 ± 14 bpm to 82 ± 10 bpm) and VOL (107 ± 13 mmHg to 100 ± 17 mmHg and 89 ± 10 bpm to 72 ± 10 bpm) exercise bouts. Together, these findings document that group III/IV muscle afferent feedback is critical for the resetting of the carotid baroreflex MAP and HR operating points, independent of exercise-induced changes in central command, but not for spontaneous carotid baroreflex responsiveness.
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Affiliation(s)
- Thomas J Hureau
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA
| | - Joshua C Weavil
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Ryan M Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA
| | - Ashley D Nelson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - D Walter Wray
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, Salt Lake City VA Medical Center, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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20
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Broxterman RM, Trinity JD, Gifford JR, Kwon OS, Kithas AC, Hydren JR, Nelson AD, Morgan DE, Jessop JE, Bledsoe AD, Richardson RS. Single passive leg movement assessment of vascular function: contribution of nitric oxide. J Appl Physiol (1985) 2017; 123:1468-1476. [PMID: 28860173 DOI: 10.1152/japplphysiol.00533.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Broxterman RM, Trinity JD, Gifford JR, Kwon OS, Kithas AC, Hydren JR, Nelson AD, Morgan DE, Jessop JE, Bledsoe AD, Richardson RS. Single passive leg movement assessment of vascular function: contribution of nitric oxide. J Appl Physiol 123: 1468-1476, 2017. First published August 31, 2017; doi:10.1152/japplphysiol.00533.2017.-The assessment of passive leg movement (PLM)-induced leg blood flow (LBF) and vascular conductance (LVC) is a novel approach to assess vascular function that has recently been simplified to only a single PLM (sPLM), thereby increasing the clinical utility of this technique. As the physiological mechanisms mediating the robust increase in LBF and LVC with sPLM are unknown, we tested the hypothesis that nitric oxide (NO) is a major contributor to the sPLM-induced LBF and LVC response. In nine healthy men, sPLM was performed with and without NO synthase inhibition by intra-arterial infusion of NG-monomethyl-l-arginine (l-NMMA). Doppler ultrasound and femoral arterial pressure were used to determine LBF and LVC, which were characterized by the peak change (ΔLBFpeak and ΔLVCpeak) and area under the curve (LBFAUC and LVCAUC). l-NMMA significantly attenuated ΔLBFpeak [492 ± 153 (l-NMMA) vs. 719 ± 238 (control) ml/min], LBFAUC [57 ± 34 (l NMMA) vs. 147 ± 63 (control) ml], ΔLVCpeak [4.7 ± 1.1 (l-NMMA) vs. 8.0 ± 3.0 (control) ml·min-1·mmHg-1], and LVCAUC [0.5 ± 0.3 (l-NMMA) vs. 1.6 ± 0.9 (control) ml/mmHg]. The magnitude of the NO contribution to LBF and LVC was significantly correlated with the magnitude of the control responses ( r = 0.94 for ΔLBFpeak, r = 0.85 for LBFAUC, r = 0.94 for ΔLVCpeak, and r = 0.95 for LVCAUC). These data establish that the sPLM-induced hyperemic and vasodilatory response is predominantly (~65%) NO-mediated. As such, sPLM appears to be a promising, simple, in vivo assessment of NO-mediated vascular function and NO bioavailability. NEW & NOTEWORTHY Passive leg movement (PLM), a novel assessment of vascular function, has been simplified to a single PLM (sPLM), thereby increasing the clinical utility of this technique. However, the role of nitric oxide (NO) in mediating the robust sPLM hemodynamic responses is unknown. This study revealed that sPLM induces a hyperemic and vasodilatory response that is predominantly NO-mediated and, as such, appears to be a promising simple, in vivo, clinical assessment of NO-mediated vascular function and, therefore, NO bioavailability.
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Affiliation(s)
- Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Oh Sung Kwon
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Andrew C Kithas
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Jay R Hydren
- Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Ashley D Nelson
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - David E Morgan
- Department of Anesthesiology, University of Utah , Salt Lake City, Utah
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah , Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah , Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
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Broxterman RM, Layec G, Hureau TJ, Morgan DE, Bledsoe AD, Jessop JE, Amann M, Richardson RS. Skeletal Muscle Force Production and Bioenergetics During All-out Exercise. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519454.23113.c3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sidhu SK, Weavil JC, Thurston TS, Wang E, Rosenberger DS, Jessop JE, Richardson RS, McNeil CJ, Amann M. Fatigue Modulates The Effect Of Group III/IV Muscle Afferents On GABAB-Mediated Inhibition And Corticospinal Excitability. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518840.08161.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kithas AC, Broxterman RM, Trinity JD, Gifford JR, Kwon OS, Hydren JR, Nelson AD, Jessop JE, Bledsoe AD, Morgan DE, Richardson RS. Determining The Window Of Effect In The Human Vasculature For The Nitric Oxide Synthase Inhibitor N(G)-monomethyl-L-arginine (L-NMMA). Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519224.07620.d2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blain GM, Mangum TS, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Richardson RS, Amann M. Group III/IV muscle afferents limit the intramuscular metabolic perturbation during whole body exercise in humans. J Physiol 2016; 594:5303-15. [PMID: 27241818 DOI: 10.1113/jp272283] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/16/2016] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS The purpose of this study was to determine the role of group III/IV muscle afferents in limiting the endurance exercise-induced metabolic perturbation assayed in muscle biopsy samples taken from locomotor muscle. Lumbar intrathecal fentanyl was used to attenuate the central projection of μ-opioid receptor-sensitive locomotor muscle afferents during a 5 km cycling time trial. The findings suggest that the central projection of group III/IV muscle afferent feedback constrains voluntary neural 'drive' to working locomotor muscle and limits the exercise-induced intramuscular metabolic perturbation. Therefore, the CNS might regulate the degree of metabolic perturbation within locomotor muscle and thereby limit peripheral fatigue. It appears that the group III/IV muscle afferents are an important neural link in this regulatory mechanism, which probably serves to protect locomotor muscle from the potentially severe functional impairment as a consequence of severe intramuscular metabolic disturbance. ABSTRACT To investigate the role of metabo- and mechanosensitive group III/IV muscle afferents in limiting the intramuscular metabolic perturbation during whole body endurance exercise, eight subjects performed 5 km cycling time trials under control conditions (CTRL) and with lumbar intrathecal fentanyl impairing lower limb muscle afferent feedback (FENT). Vastus lateralis muscle biopsies were obtained before and immediately after exercise. Motoneuronal output was estimated through vastus lateralis surface electromyography (EMG). Exercise-induced changes in intramuscular metabolites were determined using liquid and gas chromatography-mass spectrometry. Quadriceps fatigue was quantified by pre- to post-exercise changes in potentiated quadriceps twitch torque (ΔQTsingle ) evoked by electrical femoral nerve stimulation. Although motoneuronal output was 21 ± 12% higher during FENT compared to CTRL (P < 0.05), time to complete the time trial was similar (∼8.8 min). Compared to CTRL, power output during FENT was 10 ± 4% higher in the first half of the time trial, but 11 ± 5% lower in the second half (both P < 0.01). The exercise-induced increase in intramuscular inorganic phosphate, H(+) , adenosine diphosphate, lactate and phosphocreatine depletion was 55 ± 30, 62 ± 18, 129 ± 63, 47 ± 14 (P < 0.001) and 27 ± 14% (P < 0.01) greater in FENT than CTRL. ΔQTsingle was greater following FENT than CTRL (-52 ± 2 vs -31 ± 1%, P < 0.001) and this difference was positively correlated with the difference in inorganic phosphate (r(2) = 0.79; P < 0.01) and H(+) (r(2) = 0.92; P < 0.01). In conclusion, during whole body exercise, group III/IV muscle afferents provide feedback to the CNS which, in turn, constrains motoneuronal output to the active skeletal muscle. This regulatory mechanism limits the exercise-induced intramuscular metabolic perturbation, preventing an abnormal homeostatic challenge and excessive peripheral fatigue.
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Affiliation(s)
- Gregory M Blain
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.
| | - Tyler S Mangum
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Simranjit K Sidhu
- Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Discipline of Physiology, School of Medicine, The University of Adelaide, Australia
| | - Joshua C Weavil
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Thomas J Hureau
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.,Department of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA
| | - Markus Amann
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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Blain GM, Mangum TS, Sidhu SK, Weavil JC, Richardson RS, Hureau TJ, Jessop JE, Bledsoe AD, Amann M. Group III/IV Muscle Afferents Restrict Intramuscular Metabolic Perturbation In Exercising Humans. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477316.10042.43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sidhu SK, Weavil JC, Mangum TS, Rossman MJ, Jessop JE, Richardson RS, Bledsoe AD, Amann M. Group III/IV Mediated Muscle Reflexes Restrain Vascular Conductance During Exercise In Patients With Hypertension. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477571.79486.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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