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Klemcke HG, Calderon ML, Ryan KL, Xiang L, Hinojosa-Laborde C. Effects of extremity trauma on physiological responses to hemorrhage in conscious rats. J Appl Physiol (1985) 2023; 134:203-215. [PMID: 36519571 PMCID: PMC9829477 DOI: 10.1152/japplphysiol.00191.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Although physiological responses to hemorrhage are well-studied, hemorrhage is often accompanied by trauma, and it remains unclear how injury affects these responses. This study examined effects of extremity trauma on cardiorespiratory responses and survival to moderate (37%; H-37) or severe (50%; H-50) hemorrhage in rats. Transmitter and carotid catheter implantation and extremity trauma (fibular fracture and muscle injury) were conducted 2 wk, 24 h, and 90 min, respectively, before conscious hemorrhage. Mean arterial pressure (MAP) and heart rate (HR; via telemetry), and respiration rate (RR), minute volume (MV), and tidal volume (TV; via plethysmography) were measured throughout the 25 min hemorrhage and remainder of the 4 h observation period. There were four groups: 1) H-37, no trauma (NT; n = 17); 2) H-37, extremity trauma (T, n = 18); 3) H-50, NT (n = 20); and 4) H-50, T (n = 20). For H-37, during and after hemorrhage, T increased HR (P ≤ 0.031) and MV (P ≤ 0.048) compared with NT rats. During H-50, T increased HR (0.041) and MV (P = 0.043). After hemorrhage, T increased MV (P = 0.008) but decreased HR (P = 0.007) and MAP (P = 0.039). All cardiorespiratory differences between T and NT groups were intermittent. Importantly, both survival time (159.8 ± 78.2 min vs. 211.9 ± 60.3 min; P = 0.022; mean ± SD) and percent survival (45% vs. 80%; P = 0.048) were less in T versus NT rats after H-50. Trauma interacts with physiological systems in a complex manner and no single cardiorespiratory measure was sufficiently altered to indicate that it alone could account for increased mortality after H-50.NEW & NOTEWORTHY In both civilian and military settings, severe hemorrhage rarely occurs in the absence of tissue trauma, yet many animal models for the study of hemorrhage do not include significant tissue trauma. This study using conscious unrestrained rats clearly demonstrates that extremity trauma worsens the probability of survival after a severe hemorrhage. Although no single cardiorespiratory factor accounted for the increased mortality, multiple modest time-related cardiorespiratory responses to the trauma were observed suggesting that their combined dysfunction may have contributed to the reduced survival.
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Affiliation(s)
- Harold G Klemcke
- US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, San Antonio, Texas
| | - Mariam L Calderon
- US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, San Antonio, Texas
| | - Kathy L Ryan
- US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, San Antonio, Texas
| | - Lusha Xiang
- US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, San Antonio, Texas
| | - Carmen Hinojosa-Laborde
- US Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam Houston, San Antonio, Texas
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Khodadadi F, Ketabchi F, Khodabandeh Z, Tavassoli A, Lewis GF, Bahaoddini A. The effect of subdiaphragmatic vagotomy on heart rate variability and lung inflammation in rats with severe hemorrhagic shock. BMC Cardiovasc Disord 2022; 22:181. [PMID: 35439928 PMCID: PMC9020113 DOI: 10.1186/s12872-022-02594-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/28/2022] [Indexed: 11/10/2022] Open
Abstract
Background The influence of cutting the sub-diaphragmatic branch of the vagus nerve on heart rate variability (HRV) and inflammatory reaction to severe hemorrhagic shock has not been determined prior to this study. Methods Male Sprague–Dawley rats were divided into four groups of Sham, sub-diaphragmatic vagotomized (Vag), subacute (135 ± 2 min) hemorrhagic shock (SHS), and sub-diaphragmatic vagotomized with SHS (Vag + SHS). Hemodynamic parameters were recorded and HRV calculated during multiple phases in a conscious model of hemorrhagic shock. The expressions of TNF-α and iNOS were measured in the spleen and lung tissues at the conclusion of the protocol. Results Decreases in blood pressure during blood withdrawal were identical in the SHS and Vag + SHS groups. However, heart rate only decreased in the Nadir-1 phase of the SHS group. HRV indicated increased power in the very-low, low, and high (VLF, LF, and HF) frequency bands during the Nadir-1 phase of the SHS and Vag + SHS groups, albeit the values were higher in the SHS group. In the recovery phase, the HF bands were only lower in the SHS group. After hemorrhagic shock followed by resuscitation, the expression of TNF-α and iNOS increased in the spleen and lung of the SHS group, and the expression of these genes was significantly lower in the Vag + SHS group than in the SHS group. Conclusion Parasympathetic activity increases during the hypotensive phase of hemorrhagic shock, whereas the cardiac vagal tone decreases in the recovery phase. Sub-diapragmatic vagotomy blunts the cardiac vagal tone during hemorrhagic shock, but its effect is reversed in the recovery phase. The vagus nerve plays a role in proinflammatory responses in the lungs and spleen in subacute hemorrhagic shock followed by resuscitation.
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Affiliation(s)
- Fateme Khodadadi
- Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran
| | - Farzaneh Ketabchi
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Khodabandeh
- Stem Cell Technology Research Center, Shiraz University of Medical Science, Shiraz, Iran
| | - Alireza Tavassoli
- Department of Pathology, Fasa University of Medical Sciences, Fasa, Iran
| | - Gregory F Lewis
- Intelligent Systems Engineering, Indiana University, Bloomington, IN, USA.,The Traumatic Stress Research Consortium at the Kinsey Institute, Indiana University, Bloomington, IN, USA
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Yeater T, Zubcevic J, Allen K. Measures of cardiovascular function suggest autonomic nervous system dysregulation after surgical induction of joint injury in the male Lewis rat. Osteoarthritis Cartilage 2022; 30:586-595. [PMID: 35017058 PMCID: PMC9255271 DOI: 10.1016/j.joca.2021.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 11/01/2021] [Accepted: 12/02/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Functional changes in the autonomic nervous system may help explain variability in the progression of knee osteoarthritis (OA). Thus, the objective of this study was to evaluate autonomic nervous system shifts, measured via heart rate response variables, in rat knee joint injury and OA models. METHODS Cardiovascular characteristics were measured at baseline and bi-weekly for 8 weeks after skin incision, medial collateral ligament transection (MCLT), or MCLT+medial meniscus transection (MCLT+MMT). Heart rate was also assessed during a mild stressor (elevated maze). At endpoint, cardiovascular responses to mechanical knee stimuli were evaluated, as well as responses to 1-phenylbiguanide, a 5HT3A receptor agonist with reported ability to stimulate vagal responses. RESULTS During low activity, a slower heart rate occurred in MCLT (299 ± 10 bpm) and MCLT+MMT (310 ± 10 bpm) animals compared to controls (325 ± 10 bpm). Furthermore, patellar ligament mechanical stimuli produced an immediate decrease in heart rate and blood pressure in all groups. Finally, a larger drop in heart rate was observed in MCLT (252 ± 40 bpm) and MCLT+MMT (263 ± 49 bpm) following administration of 1-phenylbiguanide compared to skin incision (168 ± 45 bpm). CONCLUSIONS Acute mechanical stimulation of the patellar ligament produced drops in heart rate, suggesting a possible joint-brain connection that modulates autonomic responses. With both joint injury, cardiac vagal activation was altered in response to pharmacological stimulation, with chronic longitudinal heart rate reduction. These data provide some preliminary evidence of potential functional shifts in autonomic nervous system function in models of joint injury and OA.
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Affiliation(s)
- T.D. Yeater
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - J. Zubcevic
- Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - K.D. Allen
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA,Department of Orthopedic Surgery and Sports Medicine, College of Medicine, University of Florida, Gainesville, FL, USA,Address correspondence and reprint requests to: K.D. Allen, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL, 32610, USA. Tel: (352)-273-9337. , (K.D. Allen)
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N-Methyl-D-aspartate Glutamate Receptor Modulates Cardiovascular and Neuroendocrine Responses Evoked by Hemorrhagic Shock in Rats. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1156031. [PMID: 34423030 PMCID: PMC8378978 DOI: 10.1155/2021/1156031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/12/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022]
Abstract
Here, we report the participation of N-methyl-D-aspartate (NMDA) glutamate receptor in the mediation of cardiovascular and circulating vasopressin responses evoked by a hemorrhagic stimulus. In addition, once NMDA receptor activation is a prominent mechanism involved in nitric oxide (NO) synthesis in the brain, we investigated whether control of hemorrhagic shock by NMDA glutamate receptor was followed by changes in NO synthesis in brain supramedullary structures involved in cardiovascular and neuroendocrine control. Thus, we observed that intraperitoneal administration of the selective NMDA glutamate receptor antagonist dizocilpine maleate (MK801, 0.3 mg/kg) delayed and reduced the magnitude of hemorrhage-induced hypotension. Besides, hemorrhage induced a tachycardia response in the posthemorrhage period (i.e., recovery period) in control animals, and systemic treatment with MK801 caused a bradycardia response during hemorrhagic shock. Hemorrhagic stimulus increased plasma vasopressin levels during the recovery period and NMDA receptor antagonism increased concentration of this hormone during both the hemorrhage and postbleeding periods in relation to control animals. Moreover, hemorrhagic shock caused a decrease in NOx levels in the paraventricular nucleus of the hypothalamus (PVN), amygdala, bed nucleus of the stria terminalis (BNST), and ventral periaqueductal gray matter (vPAG). Nevertheless, treatment with MK801 did not affect these effects. Taken together, these results indicate that the NMDA glutamate receptor is involved in the hemorrhagic shock by inhibiting circulating vasopressin release. Our data also suggest a role of the NMDA receptor in tachycardia, but not in the decreased NO synthesis in the brain evoked by hemorrhage.
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Convertino VA, Koons NJ, Suresh MR. Physiology of Human Hemorrhage and Compensation. Compr Physiol 2021; 11:1531-1574. [PMID: 33577122 DOI: 10.1002/cphy.c200016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss. In this article, we begin with applying dimensional analysis for comparison of animal models, and progress to descriptions of various physiological consequences of hemorrhage. We then introduce the complementary side of compensation by detailing the complexity and integration of various compensatory mechanisms that are activated from the initiation of hemorrhage and serve to maintain adequate vital organ perfusion and hemodynamic stability in the scenario of reduced systemic delivery of oxygen until the onset of hemodynamic decompensation. New data are introduced that challenge legacy concepts related to mechanisms that underlie baroreflex functions and provide novel insights into the measurement of the integrated response of compensation to central hypovolemia known as the compensatory reserve. The impact of demographic and environmental factors on tolerance to hemorrhage is also reviewed. Finally, we describe how understanding the physiology of compensation can be translated to applications for early assessment of the clinical status and accurate triage of hypovolemic and hypotensive patients. © 2021 American Physiological Society. Compr Physiol 11:1531-1574, 2021.
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Affiliation(s)
- Victor A Convertino
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
| | - Natalie J Koons
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
| | - Mithun R Suresh
- Battlefield Healthy & Trauma Center for Human Integrative Physiology, United States Army Institute of Surgical Research, JBSA San Antonio, Texas, USA
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Khodadadi F, Bahaoddini A, Tavassoli A, Ketabchi F. Heart rate variability and pulmonary dysfunction in rats subjected to hemorrhagic shock. BMC Cardiovasc Disord 2020; 20:331. [PMID: 32652932 PMCID: PMC7353764 DOI: 10.1186/s12872-020-01606-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/29/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The activity of autonomic nervous system and its association with organ damage have not been entirely elucidated in hemorrhagic shock. The aim of this study was to investigate heart rate variability (HRV) and pulmonary gas exchange in hemorrhagic shock during unilateral subdiaphragmatic vagotomy. METHODS Male Sprague Dawley rats were randomly assigned into groups of Sham, vagotomized (Vag), hemorrhagic shock (HS) and Vag + HS. HS was induced in conscious animals by blood withdrawal until reaching to mean arterial blood pressure (MAP) of 40 ± 5 mmHg. Then, it was allowed to MAP returning toward the basal values. MAP and heart rate (HR) were recorded throughout the experiments, HRV components of low (LF, sympathetic index), high (LH, parasympathetic index), and very low (VLF, injury index) frequencies and the LF/HF ratio calculated, and the lung histological and blood gas parameters assessed. RESULTS In the initial phases of HS, the increase in HR with no change in MAP were observed in both HS and Vag + HS groups, while LF increased only in the HS group. In the second phase, HR and MAP decreased sharply in the HS group, whereas, only MAP decreased in the Vag + HS group. Meanwhile, LF and HF increased relative to their baselines in the HS and Vag + HS groups, even though the values were much pronounced in the HS group. In the third phase, HR, MAP, LF, HF, and the LF/HF ratio were returned back to their baselines in both HS and Vag + HS groups. In the Vag + HS group, the VLF was lower and HR was higher than those in the other groups. Furthermore, blood gas parameters and lung histology indicated the impairment of gas exchange in the Vag + HS group. CONCLUSIONS The sympathetic activity is predominant in the first phase, whereas the parasympathetic activity is dominant in the second and third phases of hemorrhagic shock. There is an inverse relationship between the level of VLF and lung injury in vagotomized animals subjected to hemorrhagic shock.
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Affiliation(s)
- Fateme Khodadadi
- Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran
| | | | - Alireza Tavassoli
- Department of Pathology, Fasa University of Medical Sciences, Fasa, Iran
| | - Farzaneh Ketabchi
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
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Negulyaev VO, Tarasova OS, Tarasova NV, Lukoshkova EV, Vinogradova OL, Borovik AS. Phase synchronization of baroreflex oscillations of blood pressure and pulse interval in rats: the effects of cardiac autonomic blockade and gradual blood loss. Physiol Meas 2019; 40:054003. [PMID: 30884478 DOI: 10.1088/1361-6579/ab10d6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Phase synchronization of arterial pressure (AP) and pulse interval (PI) oscillations in the low-frequency band (around 0.4 Hz in rats) is governed by baroreflex activity. In long-term stationary data recordings, such synchronization can be estimated by the coherence. The phase synchronization index (PSI) can be used as well. The aim of this study was to correlate PSI and the coherence of AP and PI under stationary conditions and to estimate the informativity of PSI as a measure of baroreflex activity during transient processes. APPROACH AP and PI were recorded in conscious Wistar rats using femoral artery catheters. To study the hemodynamics during hemorrhage, blood was gradually withdrawn (20 ml × kg-1 over 30 min) through a catheter in the carotid artery. MAIN RESULTS PSI and coherence spectra calculated from 30-minute AP and PI recordings demonstrated distinct peaks at the frequency of 0.4 Hz; these indicators correlate well with each other (Pearson r = 0.920, p < 0.0001). Both PSI and coherence were markedly suppressed by vagal blockade (methylatropine) and tended to reduce after sympathetic blockade (atenolol). Importantly, PSI demonstrated dynamic alterations during gradual hemorrhage. During the initial approx. 10 min of hemorrhage, AP did not change but PI was noticeably shortened, and PSI increased, which indicates the activation of the baroreflex. With further blood loss, baroreflex influences were not enough to prevent blood pressure from falling, and under such conditions PSI decreased. SIGNIFICANCE PSI, like coherence, is an informative measure of baroreflex activity under stationary conditions. In addition, PSI permits us to follow the coupling between the baroreflex oscillations of AP and PI during transient processes, which strengthens its informative value.
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Affiliation(s)
- Vladimir O Negulyaev
- State Research Center of the Russian Federation-Institute for Biomedical Problems, Russian Academy of Sciences, Khoroshevskoe shosse 76A, 123007, Moscow, Russia. M V Lomonosov Moscow State University, Leninskie Gory 1, 119234, Moscow, Russia. Author to whom any correspondence should be addressed
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Scully CG, Daluwatte C, Marques NR, Khan M, Salter M, Wolf J, Nelson C, Salsbury J, Enkhbaatar P, Kinsky M, Kramer GC, Strauss DG. Effect of hemorrhage rate on early hemodynamic responses in conscious sheep. Physiol Rep 2016; 4:4/7/e12739. [PMID: 27044850 PMCID: PMC4831318 DOI: 10.14814/phy2.12739] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 02/19/2016] [Indexed: 11/24/2022] Open
Abstract
Physiological compensatory mechanisms can mask the extent of hemorrhage in conscious mammals, which can be further complicated by individual tolerance and variations in hemorrhage onset and duration. We assessed the effect of hemorrhage rate on tolerance and early physiologic responses to hemorrhage in conscious sheep. Eight Merino ewes (37.4 ± 1.1 kg) were subjected to fast (1.25 mL/kg/min) and slow (0.25 mL/kg/min) hemorrhages separated by at least 3 days. Blood was withdrawn until a drop in mean arterial pressure (MAP) of >30 mmHg and returned at the end of the experiment. Continuous monitoring included MAP, central venous pressure, pulmonary artery pressure, pulse oximetry, and tissue oximetry. Cardiac output by thermodilution and arterial blood samples were also measured. The effects of fast versus slow hemorrhage rates were compared for total volume of blood removed and stoppage time (when MAP < 30 mmHg of baseline) and physiological responses during and after the hemorrhage. Estimated blood volume removed when MAP dropped 30 mmHg was 27.0 ± 4.2% (mean ± standard error) in the slow and 27.3 ± 3.2% in the fast hemorrhage (P = 0.47, paired t test between rates). Pressure and tissue oximetry responses were similar between hemorrhage rates. Heart rate increased at earlier levels of blood loss during the fast hemorrhage, but hemorrhage rate was not a significant factor for individual hemorrhage tolerance or hemodynamic responses. In 5/16 hemorrhages MAP stopping criteria was reached with <25% of blood volume removed. This study presents the physiological responses leading up to a significant drop in blood pressure in a large conscious animal model and how they are altered by the rate of hemorrhage.
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Affiliation(s)
- Christopher G Scully
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland
| | - Chathuri Daluwatte
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland
| | - Nicole R Marques
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Muzna Khan
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Michael Salter
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Jordan Wolf
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Christina Nelson
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - John Salsbury
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Perenlei Enkhbaatar
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - Michael Kinsky
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - George C Kramer
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas
| | - David G Strauss
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
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Busnardo C, Crestani CC, Fassini A, Resstel LBM, Corrêa FMA. NMDA and non-NMDA glutamate receptors in the paraventricular nucleus of the hypothalamus modulate different stages of hemorrhage-evoked cardiovascular responses in rats. Neuroscience 2016; 320:149-59. [PMID: 26861418 DOI: 10.1016/j.neuroscience.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/18/2016] [Accepted: 02/01/2016] [Indexed: 10/22/2022]
Abstract
Here we report the involvement of N-Methyl-d-Aspartate (NMDA) and non-NMDA glutamate receptors from the paraventricular nucleus of the hypothalamus (PVN) in the mediation of cardiovascular changes observed during hemorrhage and post-bleeding periods. In addition, the present study provides further evidence of the involvement of circulating vasopressin and cardiac sympathetic activity in cardiovascular responses to hemorrhage. Systemic treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50 μg/kg, i.v.) increased the latency to the onset of hypotension during hemorrhage and slowed post-bleeding recovery of blood pressure. Systemic treatment with the β1-adrenergic receptor antagonist atenolol (1 mg/kg, i.v.) also increased the latency to the onset of hypotension during hemorrhage. Moreover, atenolol reversed the hemorrhage-induced tachycardia into bradycardia. Bilateral microinjection of the selective NMDA glutamate receptor antagonist LY235959 (2 nmol/100 nL) into the PVN blocked the hypotensive response to hemorrhage and reduced the tachycardia during the post-hemorrhage period. Systemic treatment with dTyr(CH2)5(Me)AVP inhibited the effect of LY235959 on hemorrhage-induced hypotension, without affecting the post-bleeding tachycardia. PVN treatment with the selective non-NMDA receptor antagonist NBQX (2 nmol/100 nL) reduced the recovery of blood pressure to normal levels in the post-bleeding phase and reduced hemorrhage-induced tachycardia. Combined blockade of both NMDA and non-NMDA glutamate receptors in the PVN completely abolished the hypotensive response in the hemorrhage period and reduced the tachycardiac response in the post-hemorrhage period. These results indicate that local PVN glutamate neurotransmission is involved in the neural pathway mediating cardiovascular responses to hemorrhage, via an integrated control involving autonomic nervous system activity and vasopressin release into the circulation.
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Affiliation(s)
- C Busnardo
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - C C Crestani
- School of Pharmaceutical Sciences, Univ. Estadual Paulista-UNESP, Araraquara, SP, Brazil
| | - A Fassini
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - L B M Resstel
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - F M A Corrêa
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Evaluation of Heart Rate and Blood Pressure Variability as Indicators of Physiological Compensation to Hemorrhage Before Shock. Shock 2015; 43:463-9. [DOI: 10.1097/shk.0000000000000340] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hernandez ME, Hayward LF. Effect of DOCA/salt hypertension on CRF expression in the amygdala and the autonomic stress response in conscious rats. Auton Neurosci 2014; 185:83-92. [DOI: 10.1016/j.autneu.2014.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 12/26/2022]
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Hayward LF, Castellanos M, Noah C. Cardiorespiratory variability following repeat acute hypoxia in the conscious SHR versus two normotensive rat strains. Auton Neurosci 2012; 171:58-65. [PMID: 23154112 DOI: 10.1016/j.autneu.2012.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 12/26/2022]
Abstract
A link between exaggerated chemoreceptor sensitivity and hypertension has been documented in the spontaneously hypertensive rat (SHR) but has also been questioned when comparisons with normotensive strains other than the Wistar Kyoto (WKY) rat are made. To further evaluate the link between hypertension and chemoreflex sensitivity, changes in cardiorespiratory variability in response to three successive bouts of 5 min of hypoxia (21%→10%) were evaluated in conscious male SHR, and WKY and Sprague Dawley (SD) rats (n=7-8/group). In response to the first bout of hypoxia, the change in respiratory frequency (RF) was greatest in the SHR, but the increase in mean arterial pressure (MAP) was similar in both SHRs and WKY rats and all strains demonstrated a similar rise in heart rate (HR). All strains showed some level of response accommodation during subsequent bouts of hypoxia. Spectral analysis of HR variability identified a significant difference in high frequency (HF) power between strains during hypoxia, including an increase in HF power in the WKY rats, a decrease in the SHRs and little overall change in the SD rats. Alternatively, all strains demonstrated a rise in systolic arterial pressure (SAP) variability in the low frequency (LF) range in response to hypoxia but the increase was greatest in the SHR. Since SAP LF power is linked to vasosympathetic tone, these results support the hypothesis that essential hypertension is linked to exaggerated sympathetic responses to chemoreceptor stimulation but confirm that estimation of augmented reflex function cannot be determined by quantifying simple changes in MAP or HR.
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Affiliation(s)
- L F Hayward
- Univ. of Florida, Dept. Physiological Sciences, 1333 Center Dr., BSB 3-4, Gainesville, FL 32610-0144, USA.
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Boychuk CR, Hayward LF. Prenatal nicotine exposure alters postnatal cardiorespiratory integration in young male but not female rats. Exp Neurol 2011; 232:212-21. [PMID: 21945005 DOI: 10.1016/j.expneurol.2011.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/24/2011] [Accepted: 09/01/2011] [Indexed: 12/26/2022]
Abstract
The present study tested the hypothesis that prenatal nicotine exposure (PNE) induces sex specific alternations in indices of cardiorespiratory coupling during early development. Rat pups exposed to either nicotine (6 mg/kg/day) or saline (control) in utero were chronically instrumented with ECG electrodes for measurement of heart rate (HR) and respiratory frequency (RF) was monitored by whole body plethysmography on postnatal days (P)13, P16 and P26. PNE had no identifiable effect on resting respiratory frequency (RF) in either sex. There was however a strong trend (p=0.057) for resting HR to be elevated by PNE in male offspring only. Alternatively, the HR response to hypoxia (10% O(2)), was significantly blunted at P13 but significantly elevated at P26 s in the absence of any significant change in RF in PNE males only. Indicators of respiratory sinus arrhythmia (RSA) were also significantly reduced in P26 PNE males. No significant effects of PNE on HR, RF or RSA were identified in female offspring at any age. Our results demonstrate that PNE induces very specific changes in cardiorespiratory integration at select postnatal ages and these changes are more prominent in males. Additionally, alternations in cardiorespiratory integration appear to persist into later development in males only, potentially increasing the risk for cardiovascular diseases such as hypertension later in life.
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Affiliation(s)
- Carie R Boychuk
- University of Florida, College of Veterinary Medicine, Department of Physiological Sciences, Gainesville, FL 32610, USA
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Ahlgren JK, Hayward LF. Daily voluntary exercise alters the cardiovascular response to hemorrhage in conscious male rats. Auton Neurosci 2011; 160:42-52. [PMID: 21215710 PMCID: PMC3034809 DOI: 10.1016/j.autneu.2010.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 08/30/2010] [Accepted: 11/19/2010] [Indexed: 01/03/2023]
Abstract
The present study tested the hypothesis that voluntary wheel-exercised rats would better tolerate severe hemorrhage (HEM) compared to age matched sedentary (SED) controls. Conscious rats housed with (EX, n = 8) or without (SED, n = 8) a running wheel for 6 weeks underwent a 30% total blood volume HEM over 15 min and were euthanized 90 min later and brain tissue was processed for Fos-like immunoreactivity (FLI). Both EX and SED groups displayed typical responses to HEM (initial tachycardia followed by decreased HR and MAP) but at the end of HEM, mean arterial pressure (93 ± 6 vs 58 ± 3 mm Hg) and heart rate (316 ± 17 vs. 247 ± 22 bpm,) were higher in the EX vs. SED animals and 60 min following the end of HEM, HR remained significantly elevated in the EX vs SED animals. The altered HR response to HEM in the EX animals was linked to a significant difference in sympatho-vagal drive identified by heart rate variability analysis and an augmented baroreflex response to hypotension tested in a separate group of animals (n = 4-5/group). In many of the brain regions analyzed, EX rats displayed lower levels of FLI compared to SED rats. Significantly lower levels of FLI in the EX vs SED rats were identified in the middle and caudal external lateral subnucleus of the lateral parabrachial nucleus and the dorsal cap of the hypothalamic paraventricular nucleus. These results suggest that enhanced tolerance to HEM following daily exercise may result from an EX-induced reduction in excitation or exaggerated inhibition in central circuits involved in autonomic control.
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Affiliation(s)
- Joslyn K Ahlgren
- Department of Physiological Sciences, University of FL, Gainesville, 32610, United States
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Boychuk CR, Fuller DD, Hayward LF. Sex differences in heart rate variability during sleep following prenatal nicotine exposure in rat pups. Behav Brain Res 2010; 219:82-91. [PMID: 21163307 DOI: 10.1016/j.bbr.2010.12.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/19/2010] [Accepted: 12/07/2010] [Indexed: 01/13/2023]
Abstract
The influence of both prenatal nicotine exposure (PNE; 6 mg/kg/day) and sex on heart rate (HR) regulation during sleep versus wakefulness was evaluated in 13, 16 and 26 day old rat pups. Pups were chronically instrumented at least 24 h before testing. On postnatal day 13 (P13), PNE males spent significantly more time in NREM sleep and demonstrated a greater drop in HR when transitioning from quiet wake to sleep compared to age and sex matched controls (-14±5 bpm versus -1±3 bpm, respectively). Heart rate variability (HRV) analysis indicated that this state-dependent drop in HR was primarily associated with a greater reduction in sympathovagal balance (LF/HF ratio) in PNE males compared to controls. No parallel changes in indices of parasympathetic drive (HF power) were identified. In contrast, no significant effect of PNE on HR during sleep versus wakefulness was identified in P13 females. However, independent of state, a significant decrease in HF power was identified in P13 PNE females compared to controls. At P16, state-dependent differences in HR or HRV between PNE and sex-matched control pups were resolved. Additionally, at P26 no significant effect of PNE on state-dependent changes in HR or HRV was identified in either sex. Analysis of the hypothalamic peptide orexin identified that PNE induced approximately a 50% reduction in hypothalamic prepro-orexin mRNA and total mRNA was lowest in PNE males. These findings suggest that PNE induces sex dependent changes in sleep related autonomic regulation of HR during early postnatal development and these changes may be related to epigenetic alterations in the orexin system.
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Affiliation(s)
- Carie R Boychuk
- University of Florida, College of Veterinary Medicine, Department of Physiological Sciences, Gainesville, FL 32610, United States
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Boku A, Sugimura M, Morimoto Y, Hanamoto H, Niwa H. Hemodynamic and autonomic response to acute hemorrhage in streptozotocin-induced diabetic rats. Cardiovasc Diabetol 2010; 9:78. [PMID: 21106105 PMCID: PMC3004820 DOI: 10.1186/1475-2840-9-78] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 11/25/2010] [Indexed: 02/04/2023] Open
Abstract
Background The various autonomic control systems lead to characteristic changes in heart rate (HR) and blood pressure (BP) during acute hemorrhage. However, cardiovascular autonomic neuropathy due to diabetes mellitus may interfere with the normal compensation for hemorrhage. Materials and methods A controlled graded bleeding (6 - 36% loss of estimated total blood volume: ETBV) was performed in streptozotocin-induced diabetic rats (STZ rats) under a conscious state. Hemodynamic and autonomic responses to acute hemorrhage were examined using analysis of BP-HR variability. The effects of dextran treatment after hemorrhage were also examined. Results A significant reduction in mean arterial pressure began at 12% ETBV loss in STZ rats and 18% in the control rats, respectively. When blood loss reached 18% of TEBV, the decrease in HR was prominent in STD rats due to the activation of a parasympathetic drive, as indicated by the increase in high frequency (HF; 0.75~3.0 Hz) power in HR variability, while in the control rats this response was not observed. The administration of dextran prevented the activation of the parasympathetic drive in STZ rats during hemorrhaging. In the control rats, the dextran treatment sustained the initial increase in HR with reduced HF power in HR variability. Conclusion STZ rats showed different hemodynamic and autonomic responses to acute hemorrhage from the control rats. STZ rats were prone to develop bradycardiac hypotension characterized by marked parasympathetic activation during hemorrhaging. This finding suggests enhancement of the Bezold-Jarisch reflex in STZ rats. Dextran treatment to maintain a normovolemic hemorrhage state inhibits this reflex.
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Affiliation(s)
- Aiji Boku
- Department of Dental Anesthesiology Osaka University Graduate School of Dentistry, Suita, Japan.
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Westphal GA, Gonçalves AR, Bedin A, Steglich RB, Silva E, Poli-de-Figueiredo LF. Vasodilation increases pulse pressure variation, mimicking hypovolemic status in rabbits. Clinics (Sao Paulo) 2010; 65:189-94. [PMID: 20186303 PMCID: PMC2827706 DOI: 10.1590/s1807-59322010000200011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 11/03/2009] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE To test the hypothesis that pulse pressure respiratory variation (PPV) amplification, observed in hypovolemia, can also be observed during sodium nitroprusside (SNP)-induced vasodilation. INTRODUCTION PPV is largely used for early identification of cardiac responsiveness, especially when hypovolemia is suspected. PPV results from respiratory variation in transpulmonary blood flow and reflects the left ventricular preload variations during respiratory cycles. Any factor that decreases left ventricular preload can be associated with PPV amplification, as seen in hypovolemia. METHODS Ten anesthetized and mechanically ventilated rabbits underwent progressive hypotension by either controlled hemorrhage (Group 1) or intravenous SNP infusion (Group 2). Animals in Group 1 (n = 5) had graded hemorrhage induced at 10% steps until 50% of the total volume was bled. Mean arterial pressure (MAP) steps were registered and assumed as pressure targets to be reached in Group 2. Group 2 (n = 5) was subjected to a progressive SNP infusion to reach similar pressure targets as those defined in Group 1. Heart rate (HR), systolic pressure variation (SPV) and PPV were measured at each MAP step, and the values were compared between the groups. RESULTS SPV and PPV were similar between the experimental models in all steps (p > 0.16). SPV increased earlier in Group 2. CONCLUSION Both pharmacologic vasodilation and graded hemorrhage induced PPV amplification similar to that observed in hypovolemia, reinforcing the idea that amplified arterial pressure variation does not necessarily represent hypovolemic status but rather potential cardiovascular responsiveness to fluid infusion.
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Affiliation(s)
- Glauco A Westphal
- Department of Medicine, Universidade da Região de Joinville (Univille) - Joinville/SC, Brazil.
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