Science.gov

Sample records for alters cardiovascular responses

  1. Age alters the cardiovascular response to direct passive heating

    NASA Technical Reports Server (NTRS)

    Minson, C. T.; Wladkowski, S. L.; Cardell, A. F.; Pawelczyk, J. A.; Kenney, W. L.

    1998-01-01

    During direct passive heating in young men, a dramatic increase in skin blood flow is achieved by a rise in cardiac output (Qc) and redistribution of flow from the splanchnic and renal vascular beds. To examine the effect of age on these responses, seven young (Y; 23 +/- 1 yr) and seven older (O; 70 +/- 3 yr) men were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), Qc (by acetylene rebreathing), central venous pressure (via peripherally inserted central catheter), blood pressures (by brachial auscultation), skin blood flow (from increases in forearm blood flow by venous occlusion plethysmography), splanchnic blood flow (by indocyanine green clearance), renal blood flow (by p-aminohippurate clearance), and esophageal and mean skin temperatures. Qc was significantly lower in the older than in the young men (11.1 +/- 0.7 and 7.4 +/- 0.2 l/min in Y and O, respectively, at the limit of thermal tolerance; P < 0. 05), despite similar increases in esophageal and mean skin temperatures and time to reach the limit of thermal tolerance. A lower stroke volume (99 +/- 7 and 68 +/- 4 ml/beat in Y and O, respectively, P < 0.05), most likely due to an attenuated increase in inotropic function during heating, was the primary factor for the lower Qc observed in the older men. Increases in HR were similar in the young and older men; however, when expressed as a percentage of maximal HR, the older men relied on a greater proportion of their chronotropic reserve to obtain the same HR response (62 +/- 3 and 75 +/- 4% maximal HR in Y and O, respectively, P < 0.05). Furthermore, the older men redistributed less blood flow from the combined splanchnic and renal circulations at the limit of thermal tolerance (960 +/- 80 and 720 +/- 100 ml/min in Y and O, respectively, P < 0. 05). As a result of these combined attenuated responses, the older men had a significantly lower increase in total blood flow directed to

  2. Age alters the cardiovascular response to direct passive heating

    NASA Technical Reports Server (NTRS)

    Minson, C. T.; Wladkowski, S. L.; Cardell, A. F.; Pawelczyk, J. A.; Kenney, W. L.

    1998-01-01

    During direct passive heating in young men, a dramatic increase in skin blood flow is achieved by a rise in cardiac output (Qc) and redistribution of flow from the splanchnic and renal vascular beds. To examine the effect of age on these responses, seven young (Y; 23 +/- 1 yr) and seven older (O; 70 +/- 3 yr) men were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), Qc (by acetylene rebreathing), central venous pressure (via peripherally inserted central catheter), blood pressures (by brachial auscultation), skin blood flow (from increases in forearm blood flow by venous occlusion plethysmography), splanchnic blood flow (by indocyanine green clearance), renal blood flow (by p-aminohippurate clearance), and esophageal and mean skin temperatures. Qc was significantly lower in the older than in the young men (11.1 +/- 0.7 and 7.4 +/- 0.2 l/min in Y and O, respectively, at the limit of thermal tolerance; P < 0. 05), despite similar increases in esophageal and mean skin temperatures and time to reach the limit of thermal tolerance. A lower stroke volume (99 +/- 7 and 68 +/- 4 ml/beat in Y and O, respectively, P < 0.05), most likely due to an attenuated increase in inotropic function during heating, was the primary factor for the lower Qc observed in the older men. Increases in HR were similar in the young and older men; however, when expressed as a percentage of maximal HR, the older men relied on a greater proportion of their chronotropic reserve to obtain the same HR response (62 +/- 3 and 75 +/- 4% maximal HR in Y and O, respectively, P < 0.05). Furthermore, the older men redistributed less blood flow from the combined splanchnic and renal circulations at the limit of thermal tolerance (960 +/- 80 and 720 +/- 100 ml/min in Y and O, respectively, P < 0. 05). As a result of these combined attenuated responses, the older men had a significantly lower increase in total blood flow directed to

  3. Short-term physical training alters cardiovascular autonomic response amplitude and latencies.

    PubMed

    Sharma, Rajesh K; Deepak, K K; Bijlani, R L; Rao, P S

    2004-04-01

    This study reports the results of 15 days of exercise training in 25 adult males on cardiovascular autonomic response amplitude and latencies. A standard battery of autonomic function tests including both activity (tone) and reactivity was used. Parasympathetic activity as evaluated from Heart rate variability (HRV) showed no statistically significant change in both time and frequency domain measures, similarly Sympathetic activity as measured by QT/QS2 ratio showed no statistically significant change, but there was a trend of a decrease in sympathetic activity and an increase in parasympathetic activity. There were no changes in the parameters measuring parasympathetic reactivity. Sympathetic reactivity as evaluated by diastolic blood pressure responses to hand grip test (HGT) and cold pressor test (CPT) showed significant decreases. Time domain assessment of autonomic responses was done by measuring tachycardia and bradycardia latencies during Valsalva maneuver (VM) and lying to standing test (LST). Physical training resulted in a decrease in tachycardia latency during LST and a decrease in bradycardia latency during VM. We conclude from the present study that 15 days of physical training is not enough to alter autonomic activity and PNS reactivity but can result in changes in SNS reactivity and latency parameters. We hypothesize that a decrease in bradycardia latency during VM signifies a faster recovery of heart rate during VM and a decrease in tachycardia latency during LST denotes a delayed activation of the system both of which are favorable cardiovascular responses.

  4. Aging alters muscle reflex control of autonomic cardiovascular responses to rhythmic contractions in humans.

    PubMed

    Sidhu, Simranjit K; Weavil, Joshua C; Venturelli, Massimo; Rossman, Matthew J; Gmelch, Benjamin S; Bledsoe, Amber D; Richardson, Russell S; Amann, Markus

    2015-11-01

    We investigated the influence of aging on the group III/IV muscle afferents in the exercise pressor reflex-mediated cardiovascular response to rhythmic exercise. Nine old (OLD; 68 ± 2 yr) and nine young (YNG; 24 ± 2 yr) males performed single-leg knee extensor exercise (15 W, 30 W, 80% max) under control conditions and with lumbar intrathecal fentanyl impairing feedback from group III/IV leg muscle afferents. Mean arterial pressure (MAP), cardiac output, leg blood flow (QL), systemic (SVC) and leg vascular conductance (LVC) were continuously determined. With no hemodynamic effect at rest, fentanyl blockade during exercise attenuated both cardiac output and QL ∼17% in YNG, while the decrease in cardiac output in OLD (∼5%) was significantly smaller with no impact on QL (P = 0.8). Therefore, in the face of similar significant ∼7% reduction in MAP during exercise with fentanyl blockade in both groups, LVC significantly increased ∼11% in OLD, but decreased ∼8% in YNG. The opposing direction of change was reflected in SVC with a significant ∼5% increase in OLD and a ∼12% decrease in YNG. Thus while cardiac output seems to account for the majority of group III/IV-mediated MAP responses in YNG, the impact of neural feedback on the heart may decrease with age and alterations in SVC become more prominent in mediating the similar exercise pressor reflex in OLD. Interestingly, in terms of peripheral hemodynamics, while group III/IV-mediated feedback plays a clear role in increasing LVC during exercise in the YNG, these afferents seem to actually reduce LVC in OLD. These peripheral findings may help explain the limited exercise-induced peripheral vasodilation often associated with aging.

  5. Island tameness: an altered cardiovascular stress response in Galápagos marine iguanas.

    PubMed

    Vitousek, Maren N; Romero, L Michael; Tarlow, Elisa; Cyr, Nicole E; Wikelski, Martin

    2010-03-30

    Island tameness is a widely documented phenomenon in which island species, particularly those that have evolved with no or few natural predators, show a greatly reduced behavioral response when faced with unfamiliar predators. This insufficient anti-predator response has led to widespread population declines among many island species exposed to novel predators, and has become a serious conservation problem. Despite its prevalence, the underlying physiology of island tameness is not known. Here we report that although Galápagos marine iguanas (Amblyrhynchus cristatus) initiated flight from an evolutionarily recent and unfamiliar potential predator (humans), they failed to show the cardiovascular stress response that facilitates successful escape, even after a prior capture experience. In contrast, when approached by a native predator (the Galápagos hawk; Buteo galapagoensis), marine iguanas show markedly increased heart rate independent of initiating escape movement. The secretion of catecholamines appears to be central to the initiation of escape behavior: naïve animals remotely injected with epinephrine immediately increased flight initiation distance, whereas those injected with corticosterone did not. Our results provide the first evidence that muted escape behavior in predator-naïve species is indicative of both a cognitive deficit in recognizing potential predators and a catecholamine deficit in response. Understanding how the response to predators differs in predator-naïve species could enable the design of maximally effective techniques for inducing an anti-predator response in these vulnerable species.

  6. Malnutrition alters the cardiovascular responses induced by central injection of tityustoxin in Fischer rats.

    PubMed

    Silva, Fernanda Cacilda Santos; Guidine, Patrícia Alves; Ribeiro, Mara Fernandes; Fernandes, Luciano Gonçalves; Xavier, Carlos Henrique; de Menezes, Rodrigo Cunha; Silva, Marcelo Eustáquio; Moraes-Santos, Tasso; Moraes, Márcio Flávio; Chianca, Deoclécio Alves

    2013-12-15

    Scorpion envenoming and malnutrition are considered two important public health problems in Brazil, involving mainly children. Both these conditions are more common among the economically stratified lower income portion of the population, thus suggesting that these factors should be analyzed concomitantly. It is known that cardiorespiratory manifestations, as cardiac arrhythmias, arterial hypertension and hypotension, pulmonary edema and circulatory failure are the main "causa mortis" of scorpion envenomation. Additionally, there are evidences in the literature that deficiencies in dietary intake endanger the CNS and modify the cardiovascular homeostasis. Then, the objective of this work is to evaluate the protein malnourished effect on cardiovascular responses induced by tityustoxin (TsTX, an α-type toxin extracted from the Tityus serrulatus scorpion venom). Fischer rats (n = 20) were injected i.c.v. with TsTX and divided in control and malnorished groups, which were, respectively, submitted to a control and a low-protein diet. Arterial pressure recordings were done until death of the animals. Although both groups presented an increased mean arterial pressure after TsTX injection, this increase was smaller and delayed in malnourished rats, when compared to control rats. In addition, heart rate increased only in rats from the control group. Finally, malnourished rats had an increase in survival time (9:9/13.5 vs. 15.5:10.5/18 min; p = 0.0009). In summary, our results suggest that the protein restriction attenuates the cardiovascular manifestations resulting from TsTX action on CNS. Published by Elsevier Ltd.

  7. Chronic environmental warming alters cardiovascular and haematological stress responses in European perch (Perca fluviatilis).

    PubMed

    Ekström, Andreas; Jutfelt, Fredrik; Fredrik Sundström, L; Adill, Anders; Aho, Teija; Sandblom, Erik

    2016-12-01

    Environmental warming and acute stress increase cardiorespiratory activity in ectothermic animals like fish. While thermal acclimation can buffer the direct thermal effects on basal cardiorespiratory function during chronic warming, little is known about how acclimation affects stress-induced cardiorespiratory responses. We compared cardiovascular and haematological responses to chasing stress in cannulated wild European perch (Perca fluviatilis) from a reference area at natural temperature (16 °C) with perch from the 'Biotest enclosure'; an experimental system chronically warmed (22 °C) by effluents from a nuclear power plant. Routine blood pressure was similar, but Biotest perch had slightly higher resting heart rate (59.9 ± 2.8 vs 51.3 ± 2.9 beats min(-1)), although the Q 10 for heart rate was 1.3, indicating pronounced thermal compensation. Chasing stress caused hypertension and a delayed tachycardia in both groups, but the maximum heart rate increase was 2.5-fold greater in Biotest fish (43.3 ± 4.3 vs 16.9 ± 2.7 beats min(-1)). Moreover, the pulse pressure response after stress was greater in reference fish, possibly due to the less pronounced tachycardia or a greater ventricular pressure generating capacity and thermally mediated differences in aortic compliance. Baseline haematological status was also similar, but after chasing stress, the haematocrit was higher in Biotest fish due to exacerbated red blood cell swelling. This study highlights that while eurythermal fishes can greatly compensate routine cardiorespiratory functions through acclimation processes, stress-induced responses may still differ markedly. This knowledge is essential when utilising cardiorespiratory variables to quantify and compare stress responses across environmental temperatures, and to forecast energetic costs and physiological constraints in ectothermic animals under global warming.

  8. A standard blood bank donation alters the thermal and cardiovascular responses during subsequent exercise.

    PubMed

    Mora-Rodriguez, Ricardo; Aguado-Jimenez, Roberto; Del Coso, Juan; Estevez, Emma

    2012-11-01

    The fear for adverse effects of blood donation on subsequent exercise may prevent physically active people from donating. We studied the impact of a standard blood bank donation (i.e., 450-mL blood withdrawal) on the thermoregulatory and cardiovascular responses to prolonged exercise in the heat. Eight moderately trained, heat-acclimated males cycled for 1 hour at 60% in a hot environment (34.9±0.6 °C) on four occasions: 1) 2 days before blood donation (CON), 2) 2 hours after donation (DON), 3) 2 days after donation (2 DAYS), and 4) 7 days after donation (7 DAYS). Two-thirds of the blood volume withdrawn was endogenously restored before exercise in the DON trial (p<0.05). DON started with increased preexercise rectal temperature (TRE; 0.42±0.1 °C above CON; p<0.05), which resulted in high levels of hyperthermia (i.e., 39.0±0.2 °C) after 1 hour of exercise. Skin temperature (34.5±0.1 °C) and sweat rate (1.15±0.1 L/h) were not affected by DON. However, DON lowered the skin blood flow:TRE relationship and elevated heart rate (HR) above CON (12±4 beats/min; p<0.05) maintaining cardiac output. After 2 DAYS, TRE and HR were restored to CON levels while cardiac output increased above CON (6%; p<0.05) in association with reduced hemoglobin concentration (i.e., peak hemodilution). A blood bank donation increases preexercise TRE. Subsequent exercise in a hot environment results in high levels of hyperthermia and HR. These thermoregulatory and cardiovascular perturbations observed during exercise disappear 2 days after donation. © 2012 American Association of Blood Banks.

  9. Acrolein Inhalation Alters Arterial Blood Gases and Triggers Carotid Body Mediated Cardiovascular Responses in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases risk of cardiovascular morbidity and mortality, especially in individuals with underlying cardiopulmonary disease. While the mechanisms accounting for these effects are unclear, several epidemiological studies have reported decreases in oxygen ...

  10. Acrolein Inhalation Alters Arterial Blood Gases and Triggers Carotid Body Mediated Cardiovascular Responses in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases risk of cardiovascular morbidity and mortality, especially in individuals with underlying cardiopulmonary disease. While the mechanisms accounting for these effects are unclear, several epidemiological studies have reported decreases in oxygen ...

  11. [Cardiovascular alterations associated with doping].

    PubMed

    Thieme, D; Büttner, A

    2015-05-01

    Doping -the abuse of anabolic-androgenic steroids in particular- is widespread in amateur and recreational sports and does not solely represent a problem of professional sports. Excessive overdose of anabolic steroids is well documented in bodybuilding or powerlifting leading to significant side effects. Cardiovascular damages are most relevant next to adverse endocrine effects.Clinical cases as well as forensic investigations of fatalities or steroid consumption in connection with trafficking of doping agents provide only anecdotal evidence of correlations between side effects and substance abuse. Analytical verification and self-declarations of steroid users have repeatedly confirmed the presumption of weekly dosages between 300 and 2000 mg, extra to the fact that co-administration of therapeutics to treat side-effects represent a routine procedure. Beside the most frequent use of medications used to treat erectile dysfunction or estrogenic side-effects, a substantial number of antihypertensive drugs of various classes, i.e. beta-blockers, diuretics, angiotensin II receptor antagonists, calcium channel blockers, as well as ACE inhibitors were recently confiscated in relevant doping cases. The presumptive correlation between misuse of anabolic steroids and self-treatment of cardiovascular side effects was explicitly confirmed by detailed user statements.Two representative fatalities of bodybuilders were introduced to outline characteristic, often lethal side effects of excessive steroid abuse. Moreover, illustrative autopsy findings of steroid acne, thrombotic occlusion of Ramus interventricularis anterior and signs of cardiac infarctions are presented.A potential steroid abuse should be carefully considered in cases of medical consultations of patients exhibiting apparent constitutional modifications and corresponding adverse effects. Moreover, common self-medications -as frequently applied by steroid consumers- should be taken into therapeutic considerations.

  12. [Circadian alterations of the cardiovascular system].

    PubMed

    Hernandes Fernandes, E; Coelho, D; Missel Correa, J R; Kumpinski, D

    2000-01-01

    Circadian variations have been known for a long time for the influence they have on the physiological systems, including the cardiovascular system. The study of the mechanisms with circadian variation that change the function of the cardiovascular system and its diseases has increased greatly in recent years due to its clinical prominence. Through these studies, physiopathology, epidemiology and factors involved in cardiovascular diseases are more understandable. Thus, the incidence of cardiac events has been clearly associated with the morning hours, as well as the possible mechanisms involved in this variation during the daytime hours. The arterial blood pressure, plasma catecholamine levels and cortisol, platelet aggregation, and fibrinolytic system action are the most implicated mechanisms. From this knowledge, it is possible to design new therapeutic strategies that should consider the time of the day of higher risk for the onset of cardiovascular events.

  13. Cardiovascular Deconditioning in Humans: Alteration in Cardiovascular Regulation and Function During Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cohen, Richard

    1999-01-01

    Alterations in cardiovascular regulation and function that occur during and after space flight have been reported. These alterations are manifested, for example, by reduced orthostatic tolerance upon reentry to the earth's gravity from space. However, the precise physiologic mechanisms responsible for these alterations remain to be fully elucidated. Perhaps, as a result, effective countermeasures have yet to be developed. In this project we apply a powerful, new method - cardiovascular system identification (CSI) - for the study of the effects of space flight on the cardiovascular system so that effective countermeasures can be developed. CSI involves the mathematical analysis of second-to-second fluctuations in non-invasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV - respiratory activity) in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of all the physiologic mechanisms coupling these signals, CSI provides a model of the closed-loop cardiovascular regulatory state in an individual subject. The model includes quantitative descriptions of the heart rate baroreflex, autonomic function, as well as other important physiologic mechanisms. We are in the process of incorporating beat-to-beat fluctuations of stroke volume into the CSI technique in order to quantify additional physiologic mechanisms such as those involved in control of peripheral vascular resistance and alterations in cardiac contractility. We apply CSI in conjunction with the two general protocols of the Human Studies Core project. The first protocol involves ground-based, human head down tilt bed rest to simulate microgravity and acute stressors - upright tilt, standing and bicycle exercise - to provide orthostatic and exercise challenges. The second protocol is intended to be the same as the first but with the addition of sleep deprivation to determine whether

  14. Cardiovascular Deconditioning in Humans: Alteration in Cardiovascular Regulation and Function During Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cohen, Richard

    1999-01-01

    Alterations in cardiovascular regulation and function that occur during and after space flight have been reported. These alterations are manifested, for example, by reduced orthostatic tolerance upon reentry to the earth's gravity from space. However, the precise physiologic mechanisms responsible for these alterations remain to be fully elucidated. Perhaps, as a result, effective countermeasures have yet to be developed. In this project we apply a powerful, new method - cardiovascular system identification (CSI) - for the study of the effects of space flight on the cardiovascular system so that effective countermeasures can be developed. CSI involves the mathematical analysis of second-to-second fluctuations in non-invasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV - respiratory activity) in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of all the physiologic mechanisms coupling these signals, CSI provides a model of the closed-loop cardiovascular regulatory state in an individual subject. The model includes quantitative descriptions of the heart rate baroreflex, autonomic function, as well as other important physiologic mechanisms. We are in the process of incorporating beat-to-beat fluctuations of stroke volume into the CSI technique in order to quantify additional physiologic mechanisms such as those involved in control of peripheral vascular resistance and alterations in cardiac contractility. We apply CSI in conjunction with the two general protocols of the Human Studies Core project. The first protocol involves ground-based, human head down tilt bed rest to simulate microgravity and acute stressors - upright tilt, standing and bicycle exercise - to provide orthostatic and exercise challenges. The second protocol is intended to be the same as the first but with the addition of sleep deprivation to determine whether

  15. Cardiovascular response to thermoregulatory challenges

    PubMed Central

    Liu, Cuiqing; Yavar, Zubin

    2015-01-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. PMID:26432837

  16. Cardiovascular response to thermoregulatory challenges.

    PubMed

    Liu, Cuiqing; Yavar, Zubin; Sun, Qinghua

    2015-12-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. Copyright © 2015 the American Physiological Society.

  17. Cardiovascular alterations heralded by intrathecal baclofen bolus.

    PubMed

    Rifici, Carmela; D'Aleo, Giangaetano; D'Aleo, Piercataldo; Bramanti, Placido; Saltuari, Leopold; Kofler, Markus

    2011-01-01

    We describe two patients in whom serious bradycardia and arterial hypotension occurred after a small intrathecal baclofen (ITB) test bolus. Both patients suffered from severe spasticity (one due to brain injury, one due to spinal cord injury). Medical history and diagnostic examinations revealed no previous cardiological problems. Ten minutes following a 50 μg ITB bolus, patient 1 developed bradycardia (58 bpm) and incomplete right branch block, lasting for 3 hours. In patient 2, a 20 μg ITB bolus was followed after 5 minutes by severe bradycardia (30 bpm) and hypotension (60/30 mmHg), without loss of consciousness, lasting for 10 minutes. Exaggerated muscle tone was alleviated in both patients after 2 hours by the applied doses. Neither patient underwent implantation of a permanent pump system, both were continued on oral baclofen. Despite numerous unremarkable repeat cardiological exams, both patients suffered fatal cardiac arrest one and two months later, respectively. Our observations suggest that ITB may herald cardiovascular dysfunction in predisposed patients. Careful cardiological examination before ITB treatment, and close monitoring during ITB testing in particular, is advised.

  18. Characterization of Cardiovascular Alterations Induced by Different Chronic Cisplatin Treatments.

    PubMed

    Herradón, Esperanza; González, Cristina; Uranga, José A; Abalo, Raquel; Martín, Ma I; López-Miranda, Visitacion

    2017-01-01

    In the last years, many clinical studies have revealed that some cisplatin-treated cancer survivors have a significantly increased risk of cardiovascular events, being cisplatin-induced cardiovascular toxicity an increasing concern. The aim of the present work was to evaluate the cardiovascular alterations induced by different chronic cisplatin treatments, and to identify some of the mechanisms involved. Direct blood pressure, basal cardiac (left ventricle and coronary arteries) and vascular (aortic and mesenteric) functions were evaluated in chronic (5 weeks) saline- or cisplatin-treated male Wistar rats. Three different doses of cisplatin were tested (1, 2, and 3 mg/kg/week). Alterations in cardiac and vascular tissues were also investigated by immunohistochemistry, Western Blot, and or quantitative RT-PCR analysis. Cisplatin treatment provoked a significant modification of arterial blood pressure, heart rate, and basal cardiac function at the maximum dose tested. However, vascular endothelial dysfunction occurred at lower doses. The expression of collagen fibers and conexin-43 were increased in cardiac tissue in cisplatin-treated rats with doses of 2 and 3 mg/kg/week. The expression of endothelial nitric oxide synthase was also modified in cardiac and vascular tissues after cisplatin treatment. In conclusion, chronic cisplatin treatment provokes cardiac and vascular toxicity in a dose-dependent manner. Besides, vascular endothelial dysfunction occurs at lower doses than cardiac and systemic cardiovascular toxicity. Moreover, some structural changes in cardiac and vascular tissues are also patent even before any systemic cardiovascular alterations.

  19. Characterization of Cardiovascular Alterations Induced by Different Chronic Cisplatin Treatments

    PubMed Central

    Herradón, Esperanza; González, Cristina; Uranga, José A.; Abalo, Raquel; Martín, Ma I.; López-Miranda, Visitacion

    2017-01-01

    In the last years, many clinical studies have revealed that some cisplatin-treated cancer survivors have a significantly increased risk of cardiovascular events, being cisplatin-induced cardiovascular toxicity an increasing concern. The aim of the present work was to evaluate the cardiovascular alterations induced by different chronic cisplatin treatments, and to identify some of the mechanisms involved. Direct blood pressure, basal cardiac (left ventricle and coronary arteries) and vascular (aortic and mesenteric) functions were evaluated in chronic (5 weeks) saline- or cisplatin-treated male Wistar rats. Three different doses of cisplatin were tested (1, 2, and 3 mg/kg/week). Alterations in cardiac and vascular tissues were also investigated by immunohistochemistry, Western Blot, and or quantitative RT-PCR analysis. Cisplatin treatment provoked a significant modification of arterial blood pressure, heart rate, and basal cardiac function at the maximum dose tested. However, vascular endothelial dysfunction occurred at lower doses. The expression of collagen fibers and conexin-43 were increased in cardiac tissue in cisplatin-treated rats with doses of 2 and 3 mg/kg/week. The expression of endothelial nitric oxide synthase was also modified in cardiac and vascular tissues after cisplatin treatment. In conclusion, chronic cisplatin treatment provokes cardiac and vascular toxicity in a dose-dependent manner. Besides, vascular endothelial dysfunction occurs at lower doses than cardiac and systemic cardiovascular toxicity. Moreover, some structural changes in cardiac and vascular tissues are also patent even before any systemic cardiovascular alterations. PMID:28533750

  20. Characteristics of Vibration that Alter Cardiovascular Parameters in Mice.

    PubMed

    Li, Yao; Rabey, Karyne N; Schmitt, Daniel; Norton, John N; Reynolds, Randall P

    2015-07-01

    We hypothesized that short-term exposure of mice to vibration within a frequency range thought to be near the resonant frequency range of mouse tissue and at an acceleration of 0 to 1 m/s(2) would alter heart rate (HR) and mean arterial pressure (MAP). We used radiotelemetry to evaluate the cardiovascular response to vibration in C57BL/6 and CD1 male mice exposed to vertical vibration of various frequencies and accelerations. MAP was consistently increased above baseline values at an acceleration near 1 m/s(2) and a frequency of 90 Hz in both strains, and HR was increased also in C57BL/6 mice. In addition, MAP increased at 80 Hz in individual mice of both strains. When both strains were analyzed together, mean MAP and HR were increased at 90 Hz at 1 m/s(2), and HR was increased at 80 Hz at 1 m/s(2). No consistent change in MAP or HR occurred when mice were exposed to frequencies below 80 Hz or above 90 Hz. The increase in MAP and HR occurred only when the mice had conscious awareness of the vibration, given that these changes did not occur when anesthetized mice were exposed to vibration. Tested vibration acceleration levels lower than 0.75 m/s(2) did not increase MAP or HR at 80 or 90 Hz, suggesting that a relatively high level of vibration is necessary to increase these parameters. These data are important to establish the harmful frequencies and accelerations of environmental vibration that should be minimized or avoided in mouse facilities.

  1. Characteristics of Vibration that Alter Cardiovascular Parameters in Mice

    PubMed Central

    Li, Yao; Rabey, Karyne N; Schmitt, Daniel; Norton, John N; Reynolds, Randall P

    2015-01-01

    We hypothesized that short-term exposure of mice to vibration within a frequency range thought to be near the resonant frequency range of mouse tissue and at an acceleration of 0 to 1 m/s2 would alter heart rate (HR) and mean arterial pressure (MAP). We used radiotelemetry to evaluate the cardiovascular response to vibration in C57BL/6 and CD1 male mice exposed to vertical vibration of various frequencies and accelerations. MAP was consistently increased above baseline values at an acceleration near 1 m/s2 and a frequency of 90 Hz in both strains, and HR was increased also in C57BL/6 mice. In addition, MAP increased at 80 Hz in individual mice of both strains. When both strains were analyzed together, mean MAP and HR were increased at 90 Hz at 1 m/s2, and HR was increased at 80 Hz at 1 m/s2. No consistent change in MAP or HR occurred when mice were exposed to frequencies below 80 Hz or above 90 Hz. The increase in MAP and HR occurred only when the mice had conscious awareness of the vibration, given that these changes did not occur when anesthetized mice were exposed to vibration. Tested vibration acceleration levels lower than 0.75 m/s2 did not increase MAP or HR at 80 or 90 Hz, suggesting that a relatively high level of vibration is necessary to increase these parameters. These data are important to establish the harmful frequencies and accelerations of environmental vibration that should be minimized or avoided in mouse facilities. PMID:26224436

  2. Central autonomic network mediates cardiovascular responses to acute inflammation: Relevance to increased cardiovascular risk in depression?

    PubMed Central

    Harrison, Neil A.; Cooper, Ella; Voon, Valerie; Miles, Ken; Critchley, Hugo D.

    2013-01-01

    Inflammation is a risk factor for both depression and cardiovascular disease. Depressed mood is also a cardiovascular risk factor. To date, research into mechanisms through which inflammation impacts cardiovascular health rarely takes into account central effects on autonomic cardiovascular control, instead emphasizing direct effects of peripheral inflammatory responses on endothelial reactivity and myocardial function. However, brain responses to inflammation engage neural systems for motivational and homeostatic control and are expressed through depressed mood state and changes in autonomic cardiovascular regulation. Here we combined an inflammatory challenge, known to evoke an acute reduction in mood, with neuroimaging to identify the functional brain substrates underlying potentially detrimental changes in autonomic cardiovascular control. We first demonstrated that alterations in the balance of low to high frequency (LF/HF) changes in heart rate variability (a measure of baroreflex sensitivity) could account for some of the inflammation-evoked changes in diastolic blood pressure, indicating a central (rather than solely local endothelial) origin. Accompanying alterations in regional brain metabolism (measured using 18FDG-PET) were analysed to localise central mechanisms of inflammation-induced changes in cardiovascular state: three discrete regions previously implicated in stressor-evoked blood pressure reactivity, the dorsal anterior and posterior cingulate and pons, strongly mediated the relationship between inflammation and blood pressure. Moreover, activity changes within each region predicted the inflammation-induced shift in LF/HF balance. These data are consistent with a centrally-driven component originating within brain areas supporting stressor evoked blood pressure reactivity. Together our findings highlight mechanisms binding psychological and physiological well-being and their perturbation by peripheral inflammation. PMID:23416033

  3. Alterations in Cardiovascular Regulation and Function During Long-Term Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cohen, Richard J.

    1999-01-01

    The Cardiovascular Alterations Team is conducting studies of hemodynamic regulation and susceptibility to arrhythmias resulting from sixteen days of simulated microgravity exposure. In these studies very intensive measurements are made during a short duration of bed rest. In this collaborative effort are making many of the same measurements, however much less frequently, on subjects who are exposed to a much longer duration of simulated microgravity. Alterations in cardiovascular regulation and function that occur during and after space flight have been reported. These alterations are manifested, for example, by reduced orthostatic tolerance upon reentry to the earth's gravity from space. However, the precise physiologic mechanisms responsible for these alterations remain to be fully elucidated. Perhaps, as a result, effective countermeasures have yet to be developed. In addition, numerous reports from the past 30 years suggest that the incidence of ventricular arrhythmias among astronauts is increased during space flight. However, the effects of space flight and the associated physiologic stresses on cardiac conduction processes are not known, and an increase in cardiac susceptibility to arrhythmias has never been quantified. In this project we are applying the most powerful technologies available to determine, in a ground-based study of long duration space flight, the mechanisms by which space flight affects cardiovascular function, and then on the basis of an understanding of these mechanisms to develop rational and specific countermeasures. To this end we are conducting a collaborative project with the Bone Demineralization/Calcium Metabolism Team of the National Space Biomedical Research Institute (NSBRI). The Bone Team is conducting bed rest studies in human subjects lasting 17 weeks, which provides a unique opportunity to study the effects of long duration microgravity exposure on the human cardiovascular system. We are applying a number of powerful new

  4. Alterations in Cardiovascular Regulation and Function During Long-Term Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cohen, Richard J.

    1999-01-01

    The Cardiovascular Alterations Team is conducting studies of hemodynamic regulation and susceptibility to arrhythmias resulting from sixteen days of simulated microgravity exposure. In these studies very intensive measurements are made during a short duration of bed rest. In this collaborative effort are making many of the same measurements, however much less frequently, on subjects who are exposed to a much longer duration of simulated microgravity. Alterations in cardiovascular regulation and function that occur during and after space flight have been reported. These alterations are manifested, for example, by reduced orthostatic tolerance upon reentry to the earth's gravity from space. However, the precise physiologic mechanisms responsible for these alterations remain to be fully elucidated. Perhaps, as a result, effective countermeasures have yet to be developed. In addition, numerous reports from the past 30 years suggest that the incidence of ventricular arrhythmias among astronauts is increased during space flight. However, the effects of space flight and the associated physiologic stresses on cardiac conduction processes are not known, and an increase in cardiac susceptibility to arrhythmias has never been quantified. In this project we are applying the most powerful technologies available to determine, in a ground-based study of long duration space flight, the mechanisms by which space flight affects cardiovascular function, and then on the basis of an understanding of these mechanisms to develop rational and specific countermeasures. To this end we are conducting a collaborative project with the Bone Demineralization/Calcium Metabolism Team of the National Space Biomedical Research Institute (NSBRI). The Bone Team is conducting bed rest studies in human subjects lasting 17 weeks, which provides a unique opportunity to study the effects of long duration microgravity exposure on the human cardiovascular system. We are applying a number of powerful new

  5. Cardiovascular responses to hypogravic environments

    NASA Technical Reports Server (NTRS)

    Sandler, H.

    1983-01-01

    The cardiovascular deconditioning observed during and after space flight is characterized in a review of human space and simulation studies and animal simulations. The various simulation techniques (horizontal bed rest, head-down tilt, and water immersion in man, and immobilization of animals) are examined, and sample results are presented in graphs. Countermeasures such as exercise regimens, fluid replacement, drugs, venous pooling, G-suits, oscillating beds, electrostimulation of muscles, lower-body negative pressure, body-surface cooling, and hypoxia are reviewed and found to be generally ineffective or unreliable. The need for future space experimentation in both humans and animals is indicated.

  6. Cardiovascular responses to hypogravic environments

    NASA Technical Reports Server (NTRS)

    Sandler, H.

    1983-01-01

    The cardiovascular deconditioning observed during and after space flight is characterized in a review of human space and simulation studies and animal simulations. The various simulation techniques (horizontal bed rest, head-down tilt, and water immersion in man, and immobilization of animals) are examined, and sample results are presented in graphs. Countermeasures such as exercise regimens, fluid replacement, drugs, venous pooling, G-suits, oscillating beds, electrostimulation of muscles, lower-body negative pressure, body-surface cooling, and hypoxia are reviewed and found to be generally ineffective or unreliable. The need for future space experimentation in both humans and animals is indicated.

  7. Cardiovascular responses to cold exposure

    PubMed Central

    Sun, Zhongjie

    2010-01-01

    The prevalence of hypertension is increased in winter and in cold regions of the world. Cold temperatures make hypertension worse and trigger cardiovascular complications (stroke, myocardial infarction, heart failure, etc.). Chronic or intermittent exposure to cold causes hypertension and cardiac hypertrophy in animals. The purpose of this review is to provide the recent advances in the mechanistic investigation of cold-induced hypertension (CIH). Cold temperatures increase the activities of the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS). The SNS initiates CIH via the RAS. Cold exposure suppresses the expression of eNOS and formation of NO, increases the production of endothelin-1 (ET-1), up-regulates ETA receptors, but down-regulates ETB receptors. The roles of these factors and their relations in CIH will be reviewed. PMID:20036896

  8. Cardiovascular responses to cold exposure.

    PubMed

    Sun, Zhongjie

    2010-01-01

    The prevalence of hypertension is increased in winter and in cold regions of the world. Cold temperatures make hypertension worse and trigger cardiovascular complications (stroke, myocardial infarction, heart failure, etc.). Chronic or intermittent exposure to cold causes hypertension and cardiac hypertrophy in animals. The purpose of this review is to provide the recent advances in the mechanistic investigation of cold-induced hypertension (CIH). Cold temperatures increase the activities of the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS). The SNS initiates CIH via the RAS. Cold exposure suppresses the expression of eNOS and formation of NO, increases the production of endothelin-1 (ET-1), up-regulates ETA receptors, but down-regulates ETB receptors. The roles of these factors and their relations in CIH will be reviewed.

  9. Total sleep deprivation alters cardiovascular reactivity to acute stressors in humans.

    PubMed

    Yang, Huan; Durocher, John J; Larson, Robert A; Dellavalla, Joseph P; Carter, Jason R

    2012-09-01

    Exaggerated cardiovascular reactivity to mental stress (MS) and cold pressor test (CPT) has been linked to increased risk of cardiovascular disease. Recent epidemiological studies identify sleep deprivation as an important risk factor for hypertension, yet the relations between sleep deprivation and cardiovascular reactivity remain equivocal. We hypothesized that 24-h total sleep deprivation (TSD) would augment cardiovascular reactivity to MS and CPT and blunt the MS-induced forearm vasodilation. Because the associations between TSD and hypertension appear to be stronger in women, a secondary aim was to probe for sex differences. Mean arterial pressure (MAP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) were recorded during MS and CPT in 28 young, healthy subjects (14 men and 14 women) after normal sleep (NS) and 24-h TSD (randomized, crossover design). Forearm vascular conductance (FVC) was recorded during MS. MAP, FVC, and MSNA (n = 10) responses to MS were not different between NS and TSD (condition × time, P > 0.05). Likewise, MAP and MSNA (n = 6) responses to CPT were not different between NS and TSD (condition × time, P > 0.05). In contrast, increases in HR during both MS and CPT were augmented after TSD (condition × time, P ≤ 0.05), and these augmented HR responses persisted during both recoveries. When analyzed for sex differences, cardiovascular reactivity to MS and CPT was not different between sexes (condition × time × sex, P > 0.05). We conclude that TSD does not significantly alter MAP, MSNA, or forearm vascular responses to MS and CPT. The augmented tachycardia responses during and after both acute stressors provide new insight regarding the emerging links among sleep deprivation, stress, and cardiovascular risk.

  10. Hormonal, cardiovascular, and subjective responses to acute stress in smokers.

    PubMed

    Childs, Emma; de Wit, Harriet

    2009-03-01

    There are complex relationships between stress and smoking; smoking may reduce the emotional discomfort of stress, yet nicotine activates stress systems and may alter responses to acute stress. It is important to understand how smoking affects physiological and psychological outcomes after stress and how these may interact to motivate smoking. This study aimed to examine the magnitude and time course of hormonal, cardiovascular, and psychological responses to acute psychosocial stress in smokers and non-smokers to investigate whether responses to acute stress are altered in smokers. Healthy male non-smokers (n = 20) and smokers (n = 15) participated in two experimental sessions involving a standardized public speaking stress procedure and a control non-stressful task. The outcome measures included self-reported mood, cardiovascular measures (heart rate and blood pressure), and plasma hormone levels (noradrenaline, cortisol, progesterone, and allopregnanolone). Smokers exhibited blunted increases in cortisol after the Trier Social Stress Test, and they reported greater and more prolonged subjective agitation than non-smokers. Stress-induced changes in progesterone were similar between smokers and non-smokers, although responses overall were smaller among smokers. Stress did not significantly alter levels of allopregnanolone, but smokers exhibited lower plasma concentrations of this neurosteroid. These findings suggest that smoking dampens hormonal responses to stress and prolongs subjective discomfort. Dysregulated stress responses may represent a breakdown in the body's ability to cope efficiently and effectively with stress and may contribute to smokers' susceptibility to acute stress, especially during abstinence.

  11. Cardiovascular responses to static exercise in distance runners and weight lifters

    NASA Technical Reports Server (NTRS)

    Longhurst, J. C.; Kelly, A. R.; Gonyea, W. J.; Mitchell, J. H.

    1980-01-01

    Three groups of athletes including long-distance runners, competitive and amateur weight lifters, and age- and sex-matched control subjects have been studied by hemodynamic and echocardiographic methods in order to determine the effect of the training programs on the cardiovascular response to static exercise. Blood pressure, heart rate, and double product data at rest and at fatigue suggest that competitive endurance (dynamic exercise) training alters the cardiovascular response to static exercise. In contrast to endurance exercise, weight lifting (static exercise) training does not alter the cardiovascular response to static exercise: weight lifters responded to static exercise in a manner very similar to that of the control subjects.

  12. Cardiovascular responses to static exercise in distance runners and weight lifters

    NASA Technical Reports Server (NTRS)

    Longhurst, J. C.; Kelly, A. R.; Gonyea, W. J.; Mitchell, J. H.

    1980-01-01

    Three groups of athletes including long-distance runners, competitive and amateur weight lifters, and age- and sex-matched control subjects have been studied by hemodynamic and echocardiographic methods in order to determine the effect of the training programs on the cardiovascular response to static exercise. Blood pressure, heart rate, and double product data at rest and at fatigue suggest that competitive endurance (dynamic exercise) training alters the cardiovascular response to static exercise. In contrast to endurance exercise, weight lifting (static exercise) training does not alter the cardiovascular response to static exercise: weight lifters responded to static exercise in a manner very similar to that of the control subjects.

  13. Corticolimbic regulation of cardiovascular responses to stress.

    PubMed

    Myers, Brent

    2017-04-01

    Cardiovascular disease, a leading cause of death worldwide, is frequently initiated or exacerbated by stress. In fact, chronic stress exposure and heightened reactions to acute psychological stress are both associated with increased cardiovascular morbidity. This brief review focuses on the mechanisms by which corticolimbic nuclei, critical for stress appraisal and emotional reactivity, regulate heart rate and blood pressure responses to psychological stress. Both human and rodent data are examined with a major emphasis on basic studies investigating prefrontal cortex, amygdala, and hippocampus. A detailed literature review reveals substantial limitations in our understanding of this circuitry, as well as significant opportunities for future investigation that may ultimately reduce the burden of cardiovascular illness. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. The cardiovascular response to the AGS

    NASA Technical Reports Server (NTRS)

    Cardus, David; Mctaggart, Wesley G.

    1993-01-01

    This paper reports the preliminary results of experiments on human subjects conducted to study the cardiovascular response to various g-levels and exposure times using an artificial gravity simulator (AGS). The AGS is a short arm centrifuge consisting of a turntable, a traction system, a platform and four beds. Data collection hardware is part of the communication system. The AGS provides a steep acceleration gradient in subjects in the supine position.

  15. Human cardiovascular responses to passive heat stress.

    PubMed

    Crandall, Craig G; Wilson, Thad E

    2015-01-01

    Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur. © 2015 American Physiological Society.

  16. Human Cardiovascular Responses to Passive Heat Stress

    PubMed Central

    Crandall, Craig G.; Wilson, Thad E.

    2016-01-01

    Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur. PMID:25589263

  17. Physical fitness and cardiovascular response to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Raven, P. B.; Rohm-Young, D.; Blomqvist, C. G.

    1984-01-01

    Klein et al. (1977) have questioned the concept of endurance training as an appropriate means of preparing for prolonged space flights. Their opinion was mainly based on reports of endurance athletes who had a decreased tolerance to orthostatic or gravitational stress induced by lower body negative pressure (LBNP), upright tilt, or whole body water immersion. The present investigation had the objective to determine if the hemodynamic response to LBNP is different between a high and average fit group of subjects. In addition, the discrete aspect of cardiovascular function which had been altered by chronic training was to be identified. On the basis of the results of experiments conducted with 14 young male volunteers, it is concluded that the reflex response to central hypovolemia is altered by endurance exercise training.

  18. Physical fitness and cardiovascular response to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Raven, P. B.; Rohm-Young, D.; Blomqvist, C. G.

    1984-01-01

    Klein et al. (1977) have questioned the concept of endurance training as an appropriate means of preparing for prolonged space flights. Their opinion was mainly based on reports of endurance athletes who had a decreased tolerance to orthostatic or gravitational stress induced by lower body negative pressure (LBNP), upright tilt, or whole body water immersion. The present investigation had the objective to determine if the hemodynamic response to LBNP is different between a high and average fit group of subjects. In addition, the discrete aspect of cardiovascular function which had been altered by chronic training was to be identified. On the basis of the results of experiments conducted with 14 young male volunteers, it is concluded that the reflex response to central hypovolemia is altered by endurance exercise training.

  19. Implications of fundamental signalling alterations in diabetes mellitus-associated cardiovascular disease .

    PubMed

    Balakumar, Pitchai

    2014-12-01

    The chronic diabetes mellitus (DM) is a major risk factor for cardiovascular disease. The incidence of cardiovascular disease might be a foremost cause of morbidity and mortality in patients afflicted with DM. In fact, DM is associated with multi-factorial cardiovascular signalling alterations via significant modulation of expression pattern, activation or release of PI3K, PKB, eNOS, EDRF, NADPH oxidase, EDHF, CGRP, adenosine, iNOS, ROCK, PKC-β2, CaMKII, microRNA (miR)-126 and miR-130a, which could result in inadequate maintenance of cardiovascular physiology and subsequent development of cardiovascular pathology. This review highlights the possible adverse implications of fundamental cardiovascular signalling alteration in DM-associated cardiovascular disease pathology.

  20. Cardiovascular responses of snakes to hypergravity

    NASA Technical Reports Server (NTRS)

    Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Rosenberg, H. I.

    1997-01-01

    Snakes have provided useful vertebrate models for understanding circulatory adaptation to gravity, attributable to their elongate body shape and evolutionary diversificaton in terms of ecology and behavior. Recently we have studied cardiovascular responses of snakes to hypergravic acceleration forces produced acutely in the head-to-tail direction (+Gz) on a short-arm centrifuge. Snakes were held in a nearly straight position within a horizontal plastic tube and subjected to a linear force gradient during acceleration. Carotid blood flow provided an integrated measure of cardiovascular performance. Thus, cardiovascular tolerance of snakes to stepwise increments of Gz was measured as the caudal Gz force at which carotid blood flow ceased. Tolerance to increasing Gz varies according to adaptive evolutionary history inferred from the ecology and behavior of species. With respect to data for six species we investigated, multiple regression analysis demonstrates that Gz tolerance correlates with gravitational habitat, independently of body length. Relative to aquatic and non-climbing species, carotid blood flow is better maintained in arboreal or scansorial species, which tolerate hypergravic forces of +2 to +3.5 Gz. Additionally, semi-arboreal rat snakes (Elaphe obsoleta) exhibit plasticity of responses to long-term, intermittent +1.5 Gz stress. Compared to non-acclimated controls, acclimated snakes show greater increases of heart rate during head-up tilt or acceleration, greater sensitivity of arterial pressure to circulating catecholamines, higher blood levels of prostaglandin ratios favorable to maintenance of arterial blood pressure, and medial hypertrophy in major arteries and veins. As in other vertebrates, Gz tolerance of snakes is enhanced by acclimation, high arterial pressure, comparatively large blood volume, and body movements. Vascular studies of snakes suggest the importance to acclimation of local responses involving vascular tissue, in addition to

  1. Cardiovascular responses of snakes to hypergravity

    NASA Technical Reports Server (NTRS)

    Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Rosenberg, H. I.

    1997-01-01

    Snakes have provided useful vertebrate models for understanding circulatory adaptation to gravity, attributable to their elongate body shape and evolutionary diversificaton in terms of ecology and behavior. Recently we have studied cardiovascular responses of snakes to hypergravic acceleration forces produced acutely in the head-to-tail direction (+Gz) on a short-arm centrifuge. Snakes were held in a nearly straight position within a horizontal plastic tube and subjected to a linear force gradient during acceleration. Carotid blood flow provided an integrated measure of cardiovascular performance. Thus, cardiovascular tolerance of snakes to stepwise increments of Gz was measured as the caudal Gz force at which carotid blood flow ceased. Tolerance to increasing Gz varies according to adaptive evolutionary history inferred from the ecology and behavior of species. With respect to data for six species we investigated, multiple regression analysis demonstrates that Gz tolerance correlates with gravitational habitat, independently of body length. Relative to aquatic and non-climbing species, carotid blood flow is better maintained in arboreal or scansorial species, which tolerate hypergravic forces of +2 to +3.5 Gz. Additionally, semi-arboreal rat snakes (Elaphe obsoleta) exhibit plasticity of responses to long-term, intermittent +1.5 Gz stress. Compared to non-acclimated controls, acclimated snakes show greater increases of heart rate during head-up tilt or acceleration, greater sensitivity of arterial pressure to circulating catecholamines, higher blood levels of prostaglandin ratios favorable to maintenance of arterial blood pressure, and medial hypertrophy in major arteries and veins. As in other vertebrates, Gz tolerance of snakes is enhanced by acclimation, high arterial pressure, comparatively large blood volume, and body movements. Vascular studies of snakes suggest the importance to acclimation of local responses involving vascular tissue, in addition to

  2. Airway reflexes, autonomic function, and cardiovascular responses.

    PubMed Central

    Widdicombe, J; Lee, L Y

    2001-01-01

    In this article, we review the cardiovascular responses to the inhalation of irritants and pollutants. Many sensory receptors in the respiratory system, from nose to alveoli, respond to these irritants and set up powerful reflex changes, including those in the cardiovascular system. Systemic hypotension or hypertension, pulmonary hypertension, bradycardia, tachycardia, and dysrhythmias have all been described previously. Most of the experiments have been acute and have been performed on anesthetized experimental animals. Experiments on humans suggest we have similar sensory systems and reflex responses. However, we must use caution when applying the animal results to humans. Most animal experiments, unlike those with humans, have been performed using general anesthesia, with irritants administered in high concentrations, and often to a restricted part of the respiratory tract. Species differences in the response to irritants are well established. We must be even more careful when applying the results of acute experiments in animals to the pathophysiologic changes observed in prolonged exposure to environmental pollution in humans. PMID:11544167

  3. Modeling of Cardiovascular Response to Weightlessness

    NASA Technical Reports Server (NTRS)

    Sharp, M. Keith

    1999-01-01

    It was the hypothesis of this Project that the Simple lack of hydrostatic pressure in microgravity generates several purely physical reactions that underlie and may explain, in part, the cardiovascular response to weightlessness. For instance, hydrostatic pressure within the ventricles of the heart may improve cardiac performance by promoting expansion of ventricular volume during diastole. The lack of hydrostatic pressure in microgravity might, therefore, reduce diastolic filling and cardiac performance. The change in transmural pressure is possible due to the difference in hydrostatic pressure gradients between the blood inside the ventricle and the lung tissue surrounding the ventricle due to their different densities. On the other hand, hydrostatic pressure within the vasculature may reduce cardiac inlet pressures because of the typical location of the heart above the hydrostatic indifference level (the level at which pressure remains constant throughout changes in gravity). Additional physical responses of the body to changing gravitational conditions may influence cardiovascular performance. For instance, fluid shifts from the lower body to the thorax in microgravity may serve to increase central venous pressure (CVP) and boost cardiac output (CO). The concurrent release of gravitational force on the rib cage may tend to increase chest girth and decrease pedcardial pressure, augmenting ventricular filling. The lack of gravity on pulmonary tissue may allow an upward shifting of lung mass, causing a further decrease in pericardial pressure and increased CO. Additional effects include diuresis early in the flight, interstitial fluid shifts, gradual spinal extension and movement of abdominal mass, and redistribution of circulatory impedance because of venous distention in the upper body and the collapse of veins in the lower body. In this project, the cardiovascular responses to changes in intraventricular hydrostatic pressure, in intravascular hydrostatic

  4. Cardiovascular adaptations during long-term altered gravity

    NASA Technical Reports Server (NTRS)

    Popovic, V. P.

    1982-01-01

    Cardiovascular studies were performed on unrestrained, unanesthetized rats and on the same animals in head-down hypokinetic conditions as well as during readaptation of the same animals to free activity. Possible circulatory mechanisms that evolved in mammals during long-lasting gravity exposure are considered. These mechanisms are likely to be affected during exposure to 0-g forces.

  5. Cloth Ballistic Vest Alters Response to Blast

    DTIC Science & Technology

    1988-01-01

    Detrick, Frederick, MD 21701-501 ELEMENT NO. NO. NO. jACCESSION NO. 11. TITLE (include Security Classification) CLOTH BALLSISTIC VEST ALTERS RESPONSE...Suppl. ’rintd in USA Cloth Ballistic Vest Alters Response to Blast YANCY Y. PHILLIPS, M.D., THOMAS G. MUNDIE, PH.D., JOHN T. YELVERTON, M.S., AND DONALD R...RICHMOND, PH.D. Ballistic wounds have been and will remain the principal cause of casualties in combat. Cloth ballistic vests (CBV) play an

  6. Cardiovascular Responses of Snakes to Gravitational Gradients

    NASA Technical Reports Server (NTRS)

    Hsieh, Shi-Tong T.; Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Snakes are useful vertebrates for studies of gravitational adaptation, owing to their elongate body and behavioral diversification. Scansorial species have evolved specializations for regulating hemodynamics during exposure to gravitational stress, whereas, such adaptations are less well developed in aquatic and non-climbing species. We examined responses of the amphibious snake,\\italicize (Nerodia rhombifera), to increments of Gz (head-to-tail) acceleration force on both a short- and long-arm centrifuge (1.5 vs. 3.7 m radius, from the hub to tail end of snake). We recorded heart rate, dorsal aortic pressure, and carotid arterial blood flow during stepwise 0.25 G increments of Gz force (referenced at the tail) in conscious animals. The Benz tolerance of a snake was determined as the Gz level at which carotid blood flow ceased and was found to be significantly greater at the short- than long-arm centrifuge radius (1.57 Gz vs. 2.0 Gz, respectively; P=0.016). A similar pattern of response was demonstrated in semi-arboreal rat snakes,\\italicize{Elaphe obsoleta}, which are generally more tolerant of Gz force (2.6 Gz at 1.5m radius) than are water snakes. The tolerance differences of the two species reflected cardiovascular responses, which differed quantitatively but not qualitatively: heart rates increased while arterial pressure and blood flow decreased in response to increasing levels of Gz. Thus, in both species of snakes, a reduced gradient of Gz force (associated with greater centrifuge radius) significantly decreases the Gz level that can be tolerated.

  7. Cardiovascular Responses of Snakes to Gravitational Gradients

    NASA Technical Reports Server (NTRS)

    Hsieh, Shi-Tong T.; Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Snakes are useful vertebrates for studies of gravitational adaptation, owing to their elongate body and behavioral diversification. Scansorial species have evolved specializations for regulating hemodynamics during exposure to gravitational stress, whereas, such adaptations are less well developed in aquatic and non-climbing species. We examined responses of the amphibious snake,\\italicize (Nerodia rhombifera), to increments of Gz (head-to-tail) acceleration force on both a short- and long-arm centrifuge (1.5 vs. 3.7 m radius, from the hub to tail end of snake). We recorded heart rate, dorsal aortic pressure, and carotid arterial blood flow during stepwise 0.25 G increments of Gz force (referenced at the tail) in conscious animals. The Benz tolerance of a snake was determined as the Gz level at which carotid blood flow ceased and was found to be significantly greater at the short- than long-arm centrifuge radius (1.57 Gz vs. 2.0 Gz, respectively; P=0.016). A similar pattern of response was demonstrated in semi-arboreal rat snakes,\\italicize{Elaphe obsoleta}, which are generally more tolerant of Gz force (2.6 Gz at 1.5m radius) than are water snakes. The tolerance differences of the two species reflected cardiovascular responses, which differed quantitatively but not qualitatively: heart rates increased while arterial pressure and blood flow decreased in response to increasing levels of Gz. Thus, in both species of snakes, a reduced gradient of Gz force (associated with greater centrifuge radius) significantly decreases the Gz level that can be tolerated.

  8. Role of mitochondrial dysfunction and altered autophagy in cardiovascular aging and disease: from mechanisms to therapeutics.

    PubMed

    Marzetti, Emanuele; Csiszar, Anna; Dutta, Debapriya; Balagopal, Gauthami; Calvani, Riccardo; Leeuwenburgh, Christiaan

    2013-08-15

    Advanced age is associated with a disproportionate prevalence of cardiovascular disease (CVD). Intrinsic alterations in the heart and the vasculature occurring over the life course render the cardiovascular system more vulnerable to various stressors in late life, ultimately favoring the development of CVD. Several lines of evidence indicate mitochondrial dysfunction as a major contributor to cardiovascular senescence. Besides being less bioenergetically efficient, damaged mitochondria also produce increased amounts of reactive oxygen species, with detrimental structural and functional consequences for the cardiovascular system. The age-related accumulation of dysfunctional mitochondrial likely results from the combination of impaired clearance of damaged organelles by autophagy and inadequate replenishment of the cellular mitochondrial pool by mitochondriogenesis. In this review, we summarize the current knowledge about relevant mechanisms and consequences of age-related mitochondrial decay and alterations in mitochondrial quality control in the cardiovascular system. The involvement of mitochondrial dysfunction in the pathogenesis of cardiovascular conditions especially prevalent in late life and the emerging connections with neurodegeneration are also illustrated. Special emphasis is placed on recent discoveries on the role played by alterations in mitochondrial dynamics (fusion and fission), mitophagy, and their interconnections in the context of age-related CVD and endothelial dysfunction. Finally, we discuss pharmacological interventions targeting mitochondrial dysfunction to delay cardiovascular aging and manage CVD.

  9. FINE AMBIENT AIR PARTICULAR MATTER EXPOSURE INDUCES MOLECULAR ALTERATIONS INDICATIVE OF CARDIOVASCULAR DISEASE PROGRESSION IN ATHEROSCLEROTIC SUSCEPTIBLE MICE

    EPA Science Inventory

    Epidemiological, clinical, and toxicological studies have demonstrated that exposure to ambient air particulate matter (PM) can alter cardiovascular function and may influence cardiovascular disease (CVD). It has been shown that exposure to concentrated ambient air particles (CA...

  10. FINE AMBIENT AIR PARTICULAR MATTER EXPOSURE INDUCES MOLECULAR ALTERATIONS INDICATIVE OF CARDIOVASCULAR DISEASE PROGRESSION IN ATHEROSCLEROTIC SUSCEPTIBLE MICE

    EPA Science Inventory

    Epidemiological, clinical, and toxicological studies have demonstrated that exposure to ambient air particulate matter (PM) can alter cardiovascular function and may influence cardiovascular disease (CVD). It has been shown that exposure to concentrated ambient air particles (CA...

  11. Endothelium and its alterations in cardiovascular diseases: life style intervention.

    PubMed

    Favero, Gaia; Paganelli, Corrado; Buffoli, Barbara; Rodella, Luigi Fabrizio; Rezzani, Rita

    2014-01-01

    The endothelium, which forms the inner cellular lining of blood vessels and lymphatics, is a highly metabolically active organ that is involved in many physiopathological processes, including the control of vasomotor tone, barrier function, leukocyte adhesion, and trafficking and inflammation. In this review, we summarized and described the following: (i) endothelial cell function in physiological conditions and (ii) endothelial cell activation and dysfunction in the main cardiovascular diseases (such as atherosclerosis, and hypertension) and to diabetes, cigarette smoking, and aging physiological process. Finally, we presented the currently available evidence that supports the beneficial effects of physical activity and various dietary compounds on endothelial functions.

  12. Endothelium and Its Alterations in Cardiovascular Diseases: Life Style Intervention

    PubMed Central

    Paganelli, Corrado; Buffoli, Barbara; Rodella, Luigi Fabrizio; Rezzani, Rita

    2014-01-01

    The endothelium, which forms the inner cellular lining of blood vessels and lymphatics, is a highly metabolically active organ that is involved in many physiopathological processes, including the control of vasomotor tone, barrier function, leukocyte adhesion, and trafficking and inflammation. In this review, we summarized and described the following: (i) endothelial cell function in physiological conditions and (ii) endothelial cell activation and dysfunction in the main cardiovascular diseases (such as atherosclerosis, and hypertension) and to diabetes, cigarette smoking, and aging physiological process. Finally, we presented the currently available evidence that supports the beneficial effects of physical activity and various dietary compounds on endothelial functions. PMID:24719887

  13. Long-term moderate exercise accelerates the recovery of stress-evoked cardiovascular responses.

    PubMed

    Hsu, Yuan-Chang; Tsai, Sheng-Feng; Yu, Lung; Chuang, Jih-Ing; Wu, Fong-Sen; Jen, Chauying J; Kuo, Yu-Min

    2016-01-01

    Psychological stress is an important global health problem. It is well documented that stress increases the incidences of various cardiovascular disorders. Regular exercise is known to reduce resting blood pressure (BP) and heart rate (HR). This study was designed to clarify the effects of long-term exercise on stress-evoked cardiovascular responses and to emphasize post-stress recovery effects. Male Wistar rats underwent 8 weeks of moderate treadmill training, with cardiovascular responses, autonomic nervous system activities and local Fos reactivity changes in the cardiovascular regulation center were monitored before, during and after immobilization stress. A spectral analysis of cardiovascular parameters was used to examine autonomic nervous activities. We found that long-term exercise (i) lowered resting BP, HR and sympathetic activity, but increased resting parasympathetic activity and baroreflex sensitivity (BRS); (ii) accelerated post-stress recovery of stress-evoked cardiovascular and sympathetic responses along with increased BRS and (iii) accelerated post-stress recovery of stress-evoked neuron activations in the paraventricular nucleus, but delayed it in the nucleus of the tractus solitarius. We conclude that, in rats, long-term exercise accelerated recovery of stress-evoked cardiovascular responses differentially altering hypothalamic and medullar neuron activities.

  14. Melatonin modulates the fetal cardiovascular defense response to acute hypoxia

    PubMed Central

    Thakor, Avnesh S; Allison, Beth J; Niu, Youguo; Botting, Kimberley J; Serón-Ferré, Maria; Herrera, Emilio A; Giussani, Dino A

    2015-01-01

    Experimental studies in animal models supporting protective effects on the fetus of melatonin in adverse pregnancy have prompted clinical trials in human pregnancy complicated by fetal growth restriction. However, the effects of melatonin on the fetal defense to acute hypoxia, such as that which may occur during labor, remain unknown. This translational study tested the hypothesis, in vivo, that melatonin modulates the fetal cardiometabolic defense responses to acute hypoxia in chronically instrumented late gestation fetal sheep via alterations in fetal nitric oxide (NO) bioavailability. Under anesthesia, 6 fetal sheep at 0.85 gestation were instrumented with vascular catheters and a Transonic flow probe around a femoral artery. Five days later, fetuses were exposed to acute hypoxia with or without melatonin treatment. Fetal blood was taken to determine blood gas and metabolic status and plasma catecholamine concentrations. Hypoxia during melatonin treatment was repeated during in vivo NO blockade with the NO clamp. This technique permits blockade of de novo synthesis of NO while compensating for the tonic production of the gas, thereby maintaining basal cardiovascular function. Melatonin suppressed the redistribution of blood flow away from peripheral circulations and the glycemic and plasma catecholamine responses to acute hypoxia. These are important components of the fetal brain sparing response to acute hypoxia. The effects of melatonin involved NO-dependent mechanisms as the responses were reverted by fetal treatment with the NO clamp. Melatonin modulates the in vivo fetal cardiometabolic responses to acute hypoxia by increasing NO bioavailability. PMID:25908097

  15. Cardiovascular Alterations during the Interictal Period in Awake and Pithed Amygdala-Kindled Rats.

    PubMed

    Ruiz-Salinas, Inna; Rocha, Luisa; Marichal-Cancino, Bruno A; Villalón, Carlos M

    2016-08-01

    Epileptic seizures are often accompanied by increased sympathetic cardiovascular activity (even interictally), but it remains unknown whether this increased activity is of central and/or peripheral origin. Hence, this study investigated the cardiovascular alterations produced by amygdala kindling in awake and pithed Wistar rats. Blood pressure (BP) and heart rate (HR) were initially recorded by tail cuff plethysmography in awake control, sham-operated and amygdala-kindled rats before and 24 hr after the kindling process. The after-discharge threshold (ADT) was measured under different conditions to correlate brain excitability with BP and HR in kindled rats. Twenty-four hours after the last kindling seizure, (i) HR, systolic and diastolic BP were increased and (ii) only higher HR values correlated with lower ADT values. Forty-eight hr after the last kindled seizure, all rats were pithed and prepared for analysing the tachycardic, vasopressor and vasodepressor responses by (i) stimulation of the sympathetic or sensory vasodepressor CGRPergic out-flows (stimulus-response curves, S-R curves) and (ii) intravenous injections of noradrenaline or α-CGRP (dose-response curves, D-R curves). Interestingly, (i) the tachycardic S-R and D-R curves were attenuated, whilst the CGRPergic S-R and D-R curves were potentiated in kindled rats, and (ii) the vasopressor noradrenergic S-R and D-R curves were not significantly different in all groups. Therefore, the kindling process may be associated with overstimulation in the central sympathetic and sensory out-flows interictally, producing (i) peripheral attenuation of cardiac sympathetic out-flow and β-adrenoceptor activity and (ii) peripheral potentiation of vasodepressor sensory CGRPergic out-flow and CGRP receptor activity. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  16. Metabolic and Cardiovascular Responses of Children during Prolonged Physical Activity.

    ERIC Educational Resources Information Center

    Chausow, Sharon A.; And Others

    1984-01-01

    Metabolic and cardiovascular responses during 45 minutes of continuous moderate intensity exercise were investigated in 11 children, 8-11 years of age. Results indicate that children exhibit metabolic and cardiovascular adjustments similar to those noted in adults during prolonged exercise. (Author/JMK)

  17. Metabolic and Cardiovascular Responses of Children during Prolonged Physical Activity.

    ERIC Educational Resources Information Center

    Chausow, Sharon A.; And Others

    1984-01-01

    Metabolic and cardiovascular responses during 45 minutes of continuous moderate intensity exercise were investigated in 11 children, 8-11 years of age. Results indicate that children exhibit metabolic and cardiovascular adjustments similar to those noted in adults during prolonged exercise. (Author/JMK)

  18. Simultaneous cerebrovascular and cardiovascular responses during presyncope

    NASA Technical Reports Server (NTRS)

    Bondar, R. L.; Kassam, M. S.; Stein, F.; Dunphy, P. T.; Fortney, S.; Riedesel, M. L.

    1995-01-01

    BACKGROUND AND PURPOSE: Presyncope, characterized by symptoms and signs indicative of imminent syncope, can be aborted in many situations before loss of consciousness occurs. The plasticity of cerebral autoregulation in healthy humans and its behavior during this syncopal prodrome are unclear, although systemic hemodynamic instability has been suggested as a key factor in the precipitation of syncope. Using lower body negative pressure (LBNP) to simulate central hypovolemia, we previously observed falling mean flow velocities (MFVs) with maintained mean arterial blood pressure (MABP). These findings, and recent reports suggesting increased vascular tone within the cerebral vasculature at presyncope, cannot be explained by the classic static cerebral autoregulation curve; neither can they be totally explained by a recent suggestion of a rightward shift in this curve. METHODS: Four male and five female healthy volunteers were exposed to presyncopal LBNP to evaluate their cerebrovascular and cardiovascular responses by use of continuous acquisition of MFV from the right middle cerebral artery with transcranial Doppler sonography, MABP (Finapres), and heart rate (ECG). RESULTS: At presyncope, MFV dropped on average by 27.3 +/- 14% of its baseline value (P < .05), while MABP remained at 2.0 +/- 27% above its baseline level. Estimated cerebrovascular resistance increased during LBNP. The percentage change from baseline to presyncope in MFV and MABP revealed consistent decreases in MFV before MABP. CONCLUSIONS: Increased estimated cerebrovascular resistance, falling MFV, and constant MABP are evidence of an increase in cerebral vascular tone with falling flow, suggesting a downward shift in the cerebral autoregulation curve. Cerebral vessels may have a differential sensitivity to sympathetic drive or more than one type of sympathetic innervation. Future work to induce dynamic changes in MABP during LBNP may help in assessing the plasticity of the cerebral autoregulation

  19. Simultaneous cerebrovascular and cardiovascular responses during presyncope

    NASA Technical Reports Server (NTRS)

    Bondar, R. L.; Kassam, M. S.; Stein, F.; Dunphy, P. T.; Fortney, S.; Riedesel, M. L.

    1995-01-01

    BACKGROUND AND PURPOSE: Presyncope, characterized by symptoms and signs indicative of imminent syncope, can be aborted in many situations before loss of consciousness occurs. The plasticity of cerebral autoregulation in healthy humans and its behavior during this syncopal prodrome are unclear, although systemic hemodynamic instability has been suggested as a key factor in the precipitation of syncope. Using lower body negative pressure (LBNP) to simulate central hypovolemia, we previously observed falling mean flow velocities (MFVs) with maintained mean arterial blood pressure (MABP). These findings, and recent reports suggesting increased vascular tone within the cerebral vasculature at presyncope, cannot be explained by the classic static cerebral autoregulation curve; neither can they be totally explained by a recent suggestion of a rightward shift in this curve. METHODS: Four male and five female healthy volunteers were exposed to presyncopal LBNP to evaluate their cerebrovascular and cardiovascular responses by use of continuous acquisition of MFV from the right middle cerebral artery with transcranial Doppler sonography, MABP (Finapres), and heart rate (ECG). RESULTS: At presyncope, MFV dropped on average by 27.3 +/- 14% of its baseline value (P < .05), while MABP remained at 2.0 +/- 27% above its baseline level. Estimated cerebrovascular resistance increased during LBNP. The percentage change from baseline to presyncope in MFV and MABP revealed consistent decreases in MFV before MABP. CONCLUSIONS: Increased estimated cerebrovascular resistance, falling MFV, and constant MABP are evidence of an increase in cerebral vascular tone with falling flow, suggesting a downward shift in the cerebral autoregulation curve. Cerebral vessels may have a differential sensitivity to sympathetic drive or more than one type of sympathetic innervation. Future work to induce dynamic changes in MABP during LBNP may help in assessing the plasticity of the cerebral autoregulation

  20. BIOAVAILABLE AIR PARTICULATE POLLUTION CONSTITUENTS DIRECTLY ALTER CARDIOVASCULAR FUNCTION EX VIVO

    EPA Science Inventory

    Epidemiological studies have reported associations between particulate air pollution exposure and cardiovascular (CV) effects within susceptible individuals. Particle characteristics and biological mechanisms responsible for these observations are not known. We examined whether s...

  1. ALTERATIONS OF FE HOMEOSTASIS IN RAT CARDIOVASCULAR DISEASE MODELS AND ITS CONTRIBUTION TO CARDIOPULMONARY TOXICITY

    EPA Science Inventory

    Introduction: Fe homeostasis can be disrupted in human cardiovascular diseases (CVD). We addressed how dysregulation of Fe homeostasis affected the pulmonary inflammation/oxidative stress response and disease progression after exposure to Libby amphibole (LA), an asbestifonn mine...

  2. BIOAVAILABLE AIR PARTICULATE POLLUTION CONSTITUENTS DIRECTLY ALTER CARDIOVASCULAR FUNCTION EX VIVO

    EPA Science Inventory

    Epidemiological studies have reported associations between particulate air pollution exposure and cardiovascular (CV) effects within susceptible individuals. Particle characteristics and biological mechanisms responsible for these observations are not known. We examined whether s...

  3. ALTERATIONS OF FE HOMEOSTASIS IN RAT CARDIOVASCULAR DISEASE MODELS AND ITS CONTRIBUTION TO CARDIOPULMONARY TOXICITY

    EPA Science Inventory

    Introduction: Fe homeostasis can be disrupted in human cardiovascular diseases (CVD). We addressed how dysregulation of Fe homeostasis affected the pulmonary inflammation/oxidative stress response and disease progression after exposure to Libby amphibole (LA), an asbestifonn mine...

  4. Effects of aging on cardiovascular responses to parasympathetic withdrawal.

    PubMed

    Stratton, John R; Levy, Wayne C; Caldwell, James H; Jacobson, Arnold; May, Janet; Matsuoka, Dale; Madden, Ken

    2003-06-04

    The study was done to determine whether the effects of parasympathetic withdrawal on heart rate, blood pressure (BP), and systolic and diastolic function are altered with normal aging. Cardiac responses to beta-adrenergic sympathetic stimulation decline with aging as does the heart rate response to parasympathetic withdrawal, but the extent to which other responses to parasympathetic withdrawal decrease is less clear. Heart rate, BP, systolic function, and diastolic filling responses to parasympathetic withdrawal induced by atropine (0.02 mg/kg) were compared in 50 healthy subjects, 28 older (ages 65 to 80 years, mean 70 years; 18 females all on estrogen) and 22 young (age 18 to 32 years, mean 26 years; 12 females) subjects, using radionuclide angiography. Parasympathetic withdrawal in the older group caused less of an increase in heart rate (+33 vs. +48 beats/min), cardiac index (+0.6 vs. +1.5 l/m(2)), systolic blood pressure (-1 vs. +7 mm Hg), and early diastolic filling rate (+1.7 vs. +2.4 end-diastolic volumes/s) (all p < or = 0.01). At similar declines in the diastolic filling period, end-diastolic volume index (EDVI) fell substantially more in the older group (-11.6 vs. -2.4 ml/m(2), p < 0.001). The only gender difference was in diastolic filling rate, which was similar in the young males and females, but significantly less in older males than in older females. The responses to parasympathetic withdrawal as well as sympathetic stimulation decline with aging, and both contribute to the reduced cardiovascular responses to stress with advancing age.

  5. Cardiovascular and metabolic alterations in mice lacking both beta1- and beta2-adrenergic receptors.

    PubMed

    Rohrer, D K; Chruscinski, A; Schauble, E H; Bernstein, D; Kobilka, B K

    1999-06-11

    The activation state of beta-adrenergic receptors (beta-ARs) in vivo is an important determinant of hemodynamic status, cardiac performance, and metabolic rate. In order to achieve homeostasis in vivo, the cellular signals generated by beta-AR activation are integrated with signals from a number of other distinct receptors and signaling pathways. We have utilized genetic knockout models to test directly the role of beta1- and/or beta2-AR expression on these homeostatic control mechanisms. Despite total absence of beta1- and beta2-ARs, the predominant cardiovascular beta-adrenergic subtypes, basal heart rate, blood pressure, and metabolic rate do not differ from wild type controls. However, stimulation of beta-AR function by beta-AR agonists or exercise reveals significant impairments in chronotropic range, vascular reactivity, and metabolic rate. Surprisingly, the blunted chronotropic and metabolic response to exercise seen in beta1/beta2-AR double knockouts fails to impact maximal exercise capacity. Integrating the results from single beta1- and beta2-AR knockouts as well as the beta1-/beta2-AR double knock-out suggest that in the mouse, beta-AR stimulation of cardiac inotropy and chronotropy is mediated almost exclusively by the beta1-AR, whereas vascular relaxation and metabolic rate are controlled by all three beta-ARs (beta1-, beta2-, and beta3-AR). Compensatory alterations in cardiac muscarinic receptor density and vascular beta3-AR responsiveness are also observed in beta1-/beta2-AR double knockouts. In addition to its ability to define beta-AR subtype-specific functions, this genetic approach is also useful in identifying adaptive alterations that serve to maintain critical physiological setpoints such as heart rate, blood pressure, and metabolic rate when cellular signaling mechanisms are perturbed.

  6. Altered Nitric Oxide System in Cardiovascular and Renal Diseases

    PubMed Central

    Bae, Eun Hui; Ma, Seong Kwon; Kim, Soo Wan

    2016-01-01

    Nitric oxide (NO) is synthesized by a family of NO synthases (NOS), including neuronal, inducible, and endothelial NOS (n/i/eNOS). NO-mediated effects can be beneficial or harmful depending on the specific risk factors affecting the disease. In hypertension, the vascular relaxation response to acetylcholine is blunted, and that to direct NO donors is maintained. A reduction in the activity of eNOS is mainly responsible for the elevation of blood pressure, and an abnormal expression of iNOS is likely to be related to the progression of vascular dysfunction. While eNOS/nNOS-derived NO is protective against the development of atherosclerosis, iNOS-derived NO may be proatherogenic. eNOS-derived NO may prevent the progression of myocardial infarction. Myocardial ischemia/reperfusion injury is significantly enhanced in eNOS-deficient animals. An important component of heart failure is the loss of coronary vascular eNOS activity. A pressure-overload may cause severer left ventricular hypertrophy and dysfunction in eNOS null mice than in wild-type mice. iNOS-derived NO has detrimental effects on the myocardium. NO plays an important role in regulating the angiogenesis and slowing the interstitial fibrosis of the obstructed kidney. In unilateral ureteral obstruction, the expression of eNOS was decreased in the affected kidney. In triply n/i/eNOS null mice, nephrogenic diabetes insipidus developed along with reduced aquaporin-2 abundance. In chronic kidney disease model of subtotal-nephrectomized rats, treatment with NOS inhibitors decreased systemic NO production and induced left ventricular systolic dysfunction (renocardiac syndrome). PMID:27231671

  7. Gender-based differences in the cardiovascular response to standing

    NASA Technical Reports Server (NTRS)

    Gotshall, Robert W.; Tsai, Pai-Feng; Frey, Mary A. B.

    1991-01-01

    The cardiovascular responses of men and women to the stand test were compared by measuring respective values for heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance during a 5-min supine and a 5-min standing test in ten subjects of each gender. It was found that, while the male and female subjects had similar heart rate values, all other responses exhibited greater changes in men than in women. While differences in the height of the subjects did not account for differences in cardiovascular responses, no mechanism responsible for these differences could be identified.

  8. Computer model of cardiovascular control system responses to exercise

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Rummel, J. A.; Kay, F. J.

    1973-01-01

    Approaches of systems analysis and mathematical modeling together with computer simulation techniques are applied to the cardiovascular system in order to simulate dynamic responses of the system to a range of exercise work loads. A block diagram of the circulatory model is presented, taking into account arterial segments, venous segments, arterio-venous circulation branches, and the heart. A cardiovascular control system model is also discussed together with model test results.

  9. A unique microRNA profile in end-stage heart failure indicates alterations in specific cardiovascular signaling networks.

    PubMed

    Naga Prasad, Sathyamangla V; Gupta, Manveen K; Duan, Zhong-Hui; Surampudi, Venkata Suresh K; Liu, Chang-Gong; Kotwal, Ashwin; Moravec, Christine S; Starling, Randall C; Perez, Dianne M; Sen, Subha; Wu, Qingyu; Plow, Edward F; Karnik, Sadashiva

    2017-01-01

    It is well established that the gene expression patterns are substantially altered in cardiac hypertrophy and heart failure, however, less is known about the reasons behind such global differences. MicroRNAs (miRNAs) are short non-coding RNAs that can target multiple molecules to regulate wide array of proteins in diverse pathways. The goal of the study was to profile alterations in miRNA expression using end-stage human heart failure samples with an aim to build signaling network pathways using predicted targets for the altered miRNA and to determine nodal molecules regulating individual networks. Profiling of miRNAs using custom designed microarray and validation with an independent set of samples identified eight miRNAs that are altered in human heart failure including one novel miRNA yet to be implicated in cardiac pathology. To gain an unbiased perspective on global regulation by top eight altered miRNAs, functional relationship of predicted targets for these eight miRNAs were examined by network analysis. Ingenuity Pathways Analysis network algorithm was used to build global signaling networks based on the targets of altered miRNAs which allowed us to identify participating networks and nodal molecules that could contribute to cardiac pathophysiology. Majority of the nodal molecules identified in our analysis are targets of altered miRNAs and known regulators of cardiovascular signaling. Cardio-genomics heart failure gene expression public data base was used to analyze trends in expression pattern for target nodal molecules and indeed changes in expression of nodal molecules inversely correlated to miRNA alterations. We have used NF kappa B network as an example to show that targeting other molecules in the network could alter the nodal NF kappa B despite not being a miRNA target suggesting an integrated network response. Thus, using network analysis we show that altering key functional target proteins may regulate expression of the myriad signaling pathways

  10. Enhanced carotid body chemosensory activity and the cardiovascular alterations induced by intermittent hypoxia

    PubMed Central

    Iturriaga, Rodrigo; Andrade, David C.; Del Rio, Rodrigo

    2014-01-01

    The carotid body (CB) plays a main role in the maintenance of the oxygen homeostasis. The hypoxic stimulation of the CB increases the chemosensory discharge, which in turn elicits reflex sympathetic, cardiovascular, and ventilatory adjustments. An exacerbate carotid chemosensory activity has been associated with human sympathetic-mediated diseases such as hypertension, insulin resistance, heart failure, and obstructive sleep apnea (OSA). Indeed, the CB chemosensory discharge becomes tonically hypereactive in experimental models of OSA and heart failure. Chronic intermittent hypoxia (CIH), a main feature of OSA, enhances CB chemosensory baseline discharges in normoxia and in response to hypoxia, inducing sympathetic overactivity and hypertension. Oxidative stress, increased levels of ET-1, Angiotensin II and pro-inflammatory cytokines, along with a reduced production of NO in the CB, have been associated with the enhanced carotid chemosensory activity. In this review, we will discuss new evidence supporting a main role for the CB chemoreceptor in the autonomic and cardiorespiratory alterations induced by intermittent hypoxia, as well as the molecular mechanisms involved in the CB chemosensory potentiation. PMID:25520668

  11. High Molecular Weight Barley β-Glucan Alters Gut Microbiota Toward Reduced Cardiovascular Disease Risk.

    PubMed

    Wang, Yanan; Ames, Nancy P; Tun, Hein M; Tosh, Susan M; Jones, Peter J; Khafipour, Ehsan

    2016-01-01

    The physiological cholesterol-lowering benefits of β-glucan have been well documented, however, whether modulation of gut microbiota by β-glucan is associated with these physiological effects remains unknown. The objectives of this study were therefore to determine the impact of β-glucan on the composition of gut microbiota in mildly hypercholesterolemic individuals and to identify if the altered microbiota are associated with bioactivity of β-glucan in improving risk factors of cardiovascular disease (CVD). Using a randomized, controlled crossover study design, individuals received for 5-week either a treatment breakfast containing 3 g high molecular weight (HMW), 3 g low molecular weight (LMW), 5 g LMW barley β-glucan, or wheat and rice. The American Heart Association (AHA) diet served as the background diet for all treatment groups. Phases were separated by 4-week washout periods. Fecal samples were collected at the end of each intervention phase and subjected to Illumina sequencing of 16S rRNA genes. Results revealed that at the phylum level, supplementation of 3 g/d HMW β-glucan increased Bacteroidetes and decreased Firmicutes abundances compared to control (P < 0.001). At the genus level, consumption of 3 g/d HMW β-glucan increased Bacteroides (P < 0.003), tended to increase Prevotella (P < 0.1) but decreased Dorea (P < 0.1), whereas diets containing 5 g LMW β-glucan and 3 g LMW β-glucan failed to alter the gut microbiota composition. Bacteroides, Prevotella, and Dorea composition correlated (P < 0.05) with shifts of CVD risk factors, including body mass index, waist circumference, blood pressure, as well as triglyceride levels. Our data suggest that consumption of HMW β-glucan favorably alters the composition of gut microbiota and this altered microbiota profile associates with a reduction of CVD risk markers. Together, our study suggests that β-glucan induced shifts in gut microbiota in a MW-dependent manner and that might be one of the

  12. High Molecular Weight Barley β-Glucan Alters Gut Microbiota Toward Reduced Cardiovascular Disease Risk

    PubMed Central

    Wang, Yanan; Ames, Nancy P.; Tun, Hein M.; Tosh, Susan M.; Jones, Peter J.; Khafipour, Ehsan

    2016-01-01

    The physiological cholesterol-lowering benefits of β-glucan have been well documented, however, whether modulation of gut microbiota by β-glucan is associated with these physiological effects remains unknown. The objectives of this study were therefore to determine the impact of β-glucan on the composition of gut microbiota in mildly hypercholesterolemic individuals and to identify if the altered microbiota are associated with bioactivity of β-glucan in improving risk factors of cardiovascular disease (CVD). Using a randomized, controlled crossover study design, individuals received for 5-week either a treatment breakfast containing 3 g high molecular weight (HMW), 3 g low molecular weight (LMW), 5 g LMW barley β-glucan, or wheat and rice. The American Heart Association (AHA) diet served as the background diet for all treatment groups. Phases were separated by 4-week washout periods. Fecal samples were collected at the end of each intervention phase and subjected to Illumina sequencing of 16S rRNA genes. Results revealed that at the phylum level, supplementation of 3 g/d HMW β-glucan increased Bacteroidetes and decreased Firmicutes abundances compared to control (P < 0.001). At the genus level, consumption of 3 g/d HMW β-glucan increased Bacteroides (P < 0.003), tended to increase Prevotella (P < 0.1) but decreased Dorea (P < 0.1), whereas diets containing 5 g LMW β-glucan and 3 g LMW β-glucan failed to alter the gut microbiota composition. Bacteroides, Prevotella, and Dorea composition correlated (P < 0.05) with shifts of CVD risk factors, including body mass index, waist circumference, blood pressure, as well as triglyceride levels. Our data suggest that consumption of HMW β-glucan favorably alters the composition of gut microbiota and this altered microbiota profile associates with a reduction of CVD risk markers. Together, our study suggests that β-glucan induced shifts in gut microbiota in a MW-dependent manner and that might be one of the

  13. Cardiovascular responses to metipranolol and timolol eyedrops in healthy volunteers.

    PubMed Central

    Bacon, P J; Brazier, D J; Smith, R; Smith, S E

    1989-01-01

    1. Intraocular pressure and cardiovascular responses to metipranolol 0.1% and 0.3% and timolol 0.25% eyedrops were measured in a balanced single dose placebo-controlled crossover study in eight healthy volunteers aged 34-58 years. 2. Timolol 0.25% and metipranolol 0.3% reduced intraocular pressure throughout the 6 h period of observation to a similar extent. Metipranolol 0.1% was marginally less effective, significantly reducing pressure up to 4 h only. 3. No drug treatment significantly altered resting heart rate or blood pressure. Timolol 0.25% significantly reduced exercise tachycardia (P less than 0.05), an effect which was not shown by metipranolol 0.1 or 0.3%. Exertional pain in the legs occurred more frequently after timolol 0.25% and metipranolol 0.3% than after metipranolol 0.1% or placebo eyedrops. 4. Octan-1-ol/pH 7.4 buffer distribution coefficients at 37 degrees C were found to be: metipranolol 5.19, timolol 0.84, indicating that metipranolol has an approximately 6-fold greater lipid solubility. 5. It is concluded that, by comparison with timolol, metipranolol in eyedrop concentrations up to 0.3%, despite its greater lipid solubility, reaches concentrations in the systemic circulation which are less likely to affect the heart. PMID:2565117

  14. Gender-Related Differences in Cardiovascular Responses to Orthostatic Stress

    NASA Technical Reports Server (NTRS)

    Fritsch-Yelle, Janice M.; DAunno, Dominick S.; Waters, Wendy W.; Freeman-Perez, Sondra

    1999-01-01

    There is evidence that men and women have different cardiovascular responses to standing, and that women are more susceptible to orthostatic hypotension than men. The present study seeks to determine if decreased orthostatic tolerance in women is caused by diminished vasoconstrictive responses.

  15. Orthopaedic surgeons' cardiovascular response during total hip arthroplasty.

    PubMed

    Bergovec, Marko; Orlic, Dubravko

    2008-02-01

    The literature contains limited and contradictory information regarding the amount of physical effort and/or emotional stress needed to perform surgery. We therefore investigated cardiovascular response to psychophysical stress in orthopaedic surgeons while they were performing surgery. We monitored 29 male orthopaedic surgeons from four university centers while they performed total hip arthroplasties. Changes in their cardiovascular parameters were recorded by ambulatory monitoring methods. Exercise stress testing of each participant was used as a control state. We compared the cardiovascular response during surgery to energy requirements of everyday activities. Preoperative and postoperative testing showed lower values of cardiovascular parameters than during physically less difficult parts of the operation; physically more difficult phases of the operation additionally increased the values of parameters. We concluded performing total hip arthroplasty increases surgeons' cardiovascular parameters because of psychologic stress and physical effort. Excitement of the cardiovascular system during total hip arthroplasty appears similar to the excitement during moderate-intensity daily activities, such as walking the dog, leisurely bicycling, or climbing stairs.

  16. Orthopaedic Surgeons’ Cardiovascular Response During Total Hip Arthroplasty

    PubMed Central

    Orlic, Dubravko

    2008-01-01

    The literature contains limited and contradictory information regarding the amount of physical effort and/or emotional stress needed to perform surgery. We therefore investigated cardiovascular response to psychophysical stress in orthopaedic surgeons while they were performing surgery. We monitored 29 male orthopaedic surgeons from four university centers while they performed total hip arthroplasties. Changes in their cardiovascular parameters were recorded by ambulatory monitoring methods. Exercise stress testing of each participant was used as a control state. We compared the cardiovascular response during surgery to energy requirements of everyday activities. Preoperative and postoperative testing showed lower values of cardiovascular parameters than during physically less difficult parts of the operation; physically more difficult phases of the operation additionally increased the values of parameters. We concluded performing total hip arthroplasty increases surgeons’ cardiovascular parameters because of psychologic stress and physical effort. Excitement of the cardiovascular system during total hip arthroplasty appears similar to the excitement during moderate-intensity daily activities, such as walking the dog, leisurely bicycling, or climbing stairs. PMID:18196425

  17. Human cardiovascular response to sympathomimetic agents during head-down bed rest: the effect of dietary sodium

    NASA Technical Reports Server (NTRS)

    Williams, W. J.; Stuart, C. A.; Fortney, S. M.; Pietrzyk, R. A.; Chen, Y. M.; Whitson, P. A.

    1994-01-01

    Changes in sympathoadrenal function and cardiovascular deconditioning have long been recognized as a feature of the physiological adaptation to microgravity. The deconditioning process, coupled with altered hydration status, is thought to significantly contribute to orthostatic intolerance upon return to Earth gravity. The cardiovascular response to stimulation by sympathomimetic agents before, during, and after exposure to simulated microgravity was determined in healthy volunteers equilibrated on normal or high sodium diets in order to further the understanding of the deconditioning process.

  18. Human cardiovascular response to sympathomimetic agents during head-down bed rest: the effect of dietary sodium

    NASA Technical Reports Server (NTRS)

    Williams, W. J.; Stuart, C. A.; Fortney, S. M.; Pietrzyk, R. A.; Chen, Y. M.; Whitson, P. A.

    1994-01-01

    Changes in sympathoadrenal function and cardiovascular deconditioning have long been recognized as a feature of the physiological adaptation to microgravity. The deconditioning process, coupled with altered hydration status, is thought to significantly contribute to orthostatic intolerance upon return to Earth gravity. The cardiovascular response to stimulation by sympathomimetic agents before, during, and after exposure to simulated microgravity was determined in healthy volunteers equilibrated on normal or high sodium diets in order to further the understanding of the deconditioning process.

  19. Cardiovascular responses of women to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Frey, M. A. B.; Mathes, K. L.; Hoffler, G. W.

    1986-01-01

    The effects of lower body negative pressure (LBNP) on the cardiovascular response of 20 women between 23-43 years are evaluated. Calf circumference and cardiovascular data were recorded for women in the follicular and luteal phases of the menstrual cycle at -30, -40, and -50 mm Hg LBNP. The data reveal that the two menstrual phases did not cause differences in the way women respond to LBNP. It is observed that during LBNP calf circumference is enlarged; transthoracic impedance, and heart rate are increased; stroke volume, left ventricular ejection time, the Heather Index of contractility and systolic pressure, and cardiac output are reduced; and total peripheral resistance is elevated. The experimental data are compared to Montgomery et al. (1979). It is noted that the response of women to -50 mm Hg LBNP is similar to that of men; however, women adapt to stresses on the cardiovascular system with greater heart rate adjustments.

  20. Cardiovascular responses of women to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Frey, M. A. B.; Mathes, K. L.; Hoffler, G. W.

    1986-01-01

    The effects of lower body negative pressure (LBNP) on the cardiovascular response of 20 women between 23-43 years are evaluated. Calf circumference and cardiovascular data were recorded for women in the follicular and luteal phases of the menstrual cycle at -30, -40, and -50 mm Hg LBNP. The data reveal that the two menstrual phases did not cause differences in the way women respond to LBNP. It is observed that during LBNP calf circumference is enlarged; transthoracic impedance, and heart rate are increased; stroke volume, left ventricular ejection time, the Heather Index of contractility and systolic pressure, and cardiac output are reduced; and total peripheral resistance is elevated. The experimental data are compared to Montgomery et al. (1979). It is noted that the response of women to -50 mm Hg LBNP is similar to that of men; however, women adapt to stresses on the cardiovascular system with greater heart rate adjustments.

  1. The effects of pregnancy on the cardiovascular response to acute systemic isocapnic hypoxia in conscious sheep.

    PubMed

    Jellyman, J K; Gardner, D S; Edwards, C M B; Fowden, A L; Giussani, D A

    2005-07-01

    This study tested the hypothesis that pregnancy affects the cardiovascular responses to hypoxia by altering the outputs of the peripheral components of the stress system and independent of changes in P(a)CO(2). Comparison of cardiovascular and endocrine responses to acute isocapnic hypoxia between pregnant and non-pregnant ewes. Experimental laboratory. Fifteen pregnant (118 days of gestation; term is ca. 145 days) and 8 non-pregnant sheep. Chronically instrumented pregnant and non-pregnant ewes were subjected to 1 hour normoxia, 1 hour of acute systemic isocapnic hypoxia and 1 hour recovery. Arterial blood pressure, heart rate, femoral blood flow and femoral vascular conductance were recorded continuously throughout and arterial blood samples were taken during normoxia, hypoxia and recovery for the measurement of blood gas, metabolic and endocrine status. Basal blood pressure and blood glucose and lactate concentrations were lower in pregnant animals (P < 0.05). In contrast, basal cardiovascular variables and plasma concentrations of noradrenaline, adrenaline, neuropeptide Y, adrenocorticotropic hormone (ACTH) and cortisol were similar in pregnant and non-pregnant ewes. During hypoxia similar reductions in P(a)O(2) occurred in pregnant and non-pregnant animals, without alterations in P(a)CO(2) or pH(a). In non-pregnant ewes, acute hypoxia induced a transient increase in arterial pressure and sustained tachycardia without significant changes in femoral haemodynamics. Pregnancy attenuated the cardiovascular response, significantly diminishing the magnitude of the increment in heart rate throughout the hypoxic challenge (P < 0.001). However, hypoxia did not induce significant changes in blood metabolites or in plasma concentrations of any stress hormone measured in either pregnant or non-pregnant animals. Pregnancy not only affects basal but also stimulated cardiovascular function in the mother. The diminished chronotropic response to hypoxia in pregnancy is mediated

  2. Cardiovascular response during submaximal underwater treadmill exercise in stroke patients.

    PubMed

    Yoo, Jeehyun; Lim, Kil-Byung; Lee, Hong-Jae; Kwon, Yong-Geol

    2014-10-01

    To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients. Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR. SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking. Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation.

  3. Role of altered intestinal microbiota in systemic inflammation and cardiovascular disease in chronic kidney disease.

    PubMed

    Mafra, Denise; Lobo, Julie C; Barros, Amanda F; Koppe, Laetitia; Vaziri, Nosratola D; Fouque, Denis

    2014-01-01

    The normal intestinal microbiota plays a major role in the maintenance of health and disease prevention. In fact, the alteration of the intestinal microbiota has been shown to contribute to the pathogenesis of several pathological conditions, including obesity and insulin resistance, among others. Recent studies have revealed profound alterations of the gut microbial flora in patients and animals with chronic kidney disease (CKD). Alterations in the composition of the microbiome in CKD may contribute to the systemic inflammation and accumulation of gut-derived uremic toxins, which play a central role in the pathogenesis of accelerated cardiovascular disease and numerous other CKD-associated complications. This review is intended to provide a concise description of the potential role of the CKD-associated changes in the gut microbiome and its potential role the pathogenesis of inflammation and uremic toxicity. In addition, the potential efficacy of pre- and pro-biotics in the restoration of the microbiome is briefly described.

  4. CARDIOVASCULAR RESPONSES TO ULTRAFINE CARBON PARTICLE EXPOSURES IN RATS

    EPA Science Inventory

    TD-02-042 (U. KODAVANTI) GPRA # 10108

    Cardiovascular Responses to Ultrafine Carbon Particle Exposures in Rats.
    V. Harder1, B. Lentner1, A. Ziesenis1, E. Karg1, L. Ruprecht1, U. Kodavanti2, A. Stampfl3, J. Heyder1, H. Schulz1
    GSF- Institute for Inhalation Biology1, I...

  5. CARDIOVASCULAR RESPONSES TO ULTRAFINE CARBON PARTICLE EXPOSURES IN RATS

    EPA Science Inventory

    TD-02-042 (U. KODAVANTI) GPRA # 10108

    Cardiovascular Responses to Ultrafine Carbon Particle Exposures in Rats.
    V. Harder1, B. Lentner1, A. Ziesenis1, E. Karg1, L. Ruprecht1, U. Kodavanti2, A. Stampfl3, J. Heyder1, H. Schulz1
    GSF- Institute for Inhalation Biology1, I...

  6. Can bread processing conditions alter glycaemic response?

    PubMed

    Lau, Evelyn; Soong, Yean Yean; Zhou, Weibiao; Henry, Jeyakumar

    2015-04-15

    Bread is a staple food that is traditionally made from wheat flour. This study aimed to compare the starch digestibility of western baked bread and oriental steamed bread. Four types of bread were prepared: western baked bread (WBB) and oriental steamed bread (OSB), modified baked bread (MBB) made with the OSB recipe and WBB processing, and modified steamed bread (MSB) made with the WBB recipe and OSB processing. MBB showed the highest starch digestibility in vitro, followed by WBB, OSB and MSB. A similar trend was observed for glycaemic response in vivo. MBB, WBB, OSB and MSB had a glycaemic index of 75±4, 71±5, 68±5 and 65±4, respectively. Processing differences had a more pronounced effect on starch digestibility in bread, and steamed bread was healthier in terms of glycaemic response. The manipulation of processing conditions could be an innovative route to alter the glycaemic response of carbohydrate-rich foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Xenobiotic pulmonary exposure and systemic cardiovascular response via neurological links.

    PubMed

    Stapleton, Phoebe A; Abukabda, Alaeddin B; Hardy, Steven L; Nurkiewicz, Timothy R

    2015-11-15

    The cardiovascular response to xenobiotic particle exposure has been increasingly studied over the last two decades, producing an extraordinary scope and depth of research findings. With the flourishing of nanotechnology, the term "xenobiotic particles" has expanded to encompass not only air pollution particulate matter (PM) but also anthropogenic particles, such as engineered nanomaterials (ENMs). Historically, the majority of research in these fields has focused on pulmonary exposure and the adverse physiological effects associated with a host inflammatory response or direct particle-tissue interactions. Because these hypotheses can neither account entirely for the deleterious cardiovascular effects of xenobiotic particle exposure nor their time course, the case for substantial neurological involvement is apparent. Indeed, considerable evidence suggests that not only is neural involvement a significant contributor but also a reality that needs to be investigated more thoroughly when assessing xenobiotic particle toxicities. Therefore, the scope of this review is several-fold. First, we provide a brief overview of the major anatomical components of the central and peripheral nervous systems, giving consideration to the potential biologic targets affected by inhaled particles. Second, the autonomic arcs and mechanisms that may be involved are reviewed. Third, the cardiovascular outcomes following neurological responses are discussed. Lastly, unique problems, future risks, and hurdles associated with xenobiotic particle exposure are discussed. A better understanding of these neural issues may facilitate research that in conjunction with existing research, will ultimately prevent the untoward cardiovascular outcomes associated with PM exposures and/or identify safe ENMs for the advancement of human health.

  8. Hostility, sodium consumption, and cardiovascular response to interpersonal stress.

    PubMed

    Miller, S B; Friese, M; Dolgoy, L; Sita, A; Lavoie, K; Campbell, T

    1998-01-01

    Previous studies have reported poorer health behaviors in high vs. low hostile subjects. The role of stress in these observed differences has not been explored although interpersonal stress does increase cardiovascular response in high hostiles. Given evidence that stress may induce increased salt-intake, this study examined the role of hostility and interpersonal stress in increasing sodium consumption in addition to cardiovascular reactivity. Sixty-nine male undergraduates were categorized into high (HiHo) and low hostile (LoHo) groups based on Buss-Durkee Hostility Inventory scores. Subjects engaged in either a math task with harassment, math task without harassment, or a control/rest condition. Sodium intake was assessed posttask by having subjects ingest a sodium-free soup that was presented with a saltshaker without any comments. Cardiovascular measures were also recorded. HiHo subjects consumed more salt than LoHo subjects irrespective of experimental condition. HiHo subjects who were harassed also exhibited greater cardiac output, systolic blood pressure, and forearm blood flow than did HiHo nonharassed, HiHo control, or LoHo subjects. HiHo subjects exhibited increased salt-intake, although evidence for stress-induced salt-intake was not obtained. Nonetheless, the combination of salt and stress may contribute to the cardiovascular hyperreactivity and risk for cardiovascular disease in hostile individuals.

  9. Sex, outcome expectancy, and cardiovascular response to a masculine challenge.

    PubMed

    Wright, Rex A; Lockard, Stephanie

    2006-03-01

    Male and female participants were led to believe they could secure a low or high chance of winning a prize by meeting a modest standard on a purportedly masculine task, that is, a task on which men ostensibly had higher ability. As expected, systolic blood pressure responses measured during performance were greater for women than men when the chance of winning was high, but low for both groups when the chance of winning was low. Similar effects were observed for diastolic and mean arterial pressure responses, although analysis of the mean arterial pressure data produced only a main effect for the chance factor. These results conceptually replicate cardiovascular findings obtained in a previous sex difference study. They also confirm the implication of previous ability perception studies that effort-related cardiovascular responses should be low for both sexes when the importance of meeting a gender-relevant challenge is low.

  10. A unique microRNA profile in end-stage heart failure indicates alterations in specific cardiovascular signaling networks

    PubMed Central

    Duan, Zhong-Hui; Surampudi, Venkata Suresh K.; Liu, Chang-Gong; Kotwal, Ashwin; Moravec, Christine S.; Starling, Randall C.; Perez, Dianne M.; Sen, Subha; Wu, Qingyu; Plow, Edward F.; Karnik, Sadashiva

    2017-01-01

    It is well established that the gene expression patterns are substantially altered in cardiac hypertrophy and heart failure, however, less is known about the reasons behind such global differences. MicroRNAs (miRNAs) are short non-coding RNAs that can target multiple molecules to regulate wide array of proteins in diverse pathways. The goal of the study was to profile alterations in miRNA expression using end-stage human heart failure samples with an aim to build signaling network pathways using predicted targets for the altered miRNA and to determine nodal molecules regulating individual networks. Profiling of miRNAs using custom designed microarray and validation with an independent set of samples identified eight miRNAs that are altered in human heart failure including one novel miRNA yet to be implicated in cardiac pathology. To gain an unbiased perspective on global regulation by top eight altered miRNAs, functional relationship of predicted targets for these eight miRNAs were examined by network analysis. Ingenuity Pathways Analysis network algorithm was used to build global signaling networks based on the targets of altered miRNAs which allowed us to identify participating networks and nodal molecules that could contribute to cardiac pathophysiology. Majority of the nodal molecules identified in our analysis are targets of altered miRNAs and known regulators of cardiovascular signaling. Cardio-genomics heart failure gene expression public data base was used to analyze trends in expression pattern for target nodal molecules and indeed changes in expression of nodal molecules inversely correlated to miRNA alterations. We have used NF kappa B network as an example to show that targeting other molecules in the network could alter the nodal NF kappa B despite not being a miRNA target suggesting an integrated network response. Thus, using network analysis we show that altering key functional target proteins may regulate expression of the myriad signaling pathways

  11. Role of arterial baroreceptors in mediating cardiovascular response to exercise

    NASA Technical Reports Server (NTRS)

    Mcritchie, R. J.; Vatner, S. F.; Patrick, T. A.; Braunwald, E.; Boettcher, D.; Heyndrickx, G. R.

    1976-01-01

    Experiments were conducted to define the role of the major arterial baroreceptors during moderately severe exercise by comparing the responses of untethered conscious dogs instrumented for the measurement of aortic pressure and cardiac output with those of dogs with total arterial baroreceptor denervation. The reflex heart rate responses to intravenous bolus doses of methoxamine were also examined in intact animals, both at rest and during exercise. Methoxamine is found to cause striking bradycardia at rest, but little bradycardia during exercise. Experimental findings suggest that the arterial baroreceptor reflex is normally inhibited during severe exercise and therefore plays little role in modulating the cardiovascular response to exercise.

  12. Role of arterial baroreceptors in mediating cardiovascular response to exercise

    NASA Technical Reports Server (NTRS)

    Mcritchie, R. J.; Vatner, S. F.; Patrick, T. A.; Braunwald, E.; Boettcher, D.; Heyndrickx, G. R.

    1976-01-01

    Experiments were conducted to define the role of the major arterial baroreceptors during moderately severe exercise by comparing the responses of untethered conscious dogs instrumented for the measurement of aortic pressure and cardiac output with those of dogs with total arterial baroreceptor denervation. The reflex heart rate responses to intravenous bolus doses of methoxamine were also examined in intact animals, both at rest and during exercise. Methoxamine is found to cause striking bradycardia at rest, but little bradycardia during exercise. Experimental findings suggest that the arterial baroreceptor reflex is normally inhibited during severe exercise and therefore plays little role in modulating the cardiovascular response to exercise.

  13. High density lipoproteins and endothelial functions: mechanistic insights and alterations in cardiovascular disease1

    PubMed Central

    Riwanto, Meliana; Landmesser, Ulf

    2013-01-01

    Prospective population studies in the primary prevention setting have shown that reduced plasma levels of HDL cholesterol are associated with an increased risk of coronary disease and myocardial infarction. Experimental and translational studies have further revealed several potential anti-atherogenic effects of HDL, including protective effects on endothelial cell functions. HDL has been suggested to protect endothelial cell functions by prevention of oxidation of LDL and its adverse endothelial effects. Moreover, HDL from healthy subjects can directly stimulate endothelial cell production of nitric oxide and anti-inflammatory, anti-apoptotic, and anti-thrombotic effects as well as endothelial repair processes. However, several recent clinical trials using HDL cholesterol-raising agents, such as torcetrapib, dalcetrapib, and niacin, did not demonstrate a significant reduction of cardiovascular events in patients with coronary disease. Of note, growing evidence suggests that the vascular effects of HDL can be highly heterogeneous and vasoprotective properties of HDL are altered in patients with coronary disease. Characterization of underlying mechanisms and understanding of the clinical relevance of this “HDL dysfunction” is currently an active field of cardiovascular research. Notably, in some recent studies no clear association of higher HDL cholesterol levels with a reduced risk of cardiovascular events was observed in patients with already established coronary disease. A greater understanding of mechanisms of action of HDL and its altered vascular effects is therefore critical within the context of HDL-targeted therapies. In this review, we will address different effects of HDL on endothelial cell functions potentially relevant to atherosclerotic vascular disease and explore molecular mechanisms leading to “dysfunctional HDL”. PMID:23873269

  14. Adverse life events, cardiovascular responses, and sports performance under pressure.

    PubMed

    Moore, Lee J; Young, Tom; Freeman, Paul; Sarkar, Mustafa

    2017-06-05

    Research suggests that experiencing a moderate number of adverse life events can benefit future stress responses. This study explored the relationship between adverse life (ie, non-sport) events and cardiovascular responses to, and performance during, a pressurized sporting task. One hundred participants (64 men, 36 women; Mage =21.94 years, SDage =4.98) reported the number of adverse life events (eg, serious accident or injury) they had encountered before completing a pressurized dart-throwing task during which performance was recorded. Before the task, participants' demand and resource evaluations and cardiovascular reactivity were assessed. Adverse life events did not impact demand and resource evaluations. However, participants who reported 4-7 adverse life events displayed cardiovascular responses more reflective of a challenge state (relatively lower total peripheral resistance and/or higher cardiac output) compared to those who reported a lower (<4) or higher (>7) number of events. Furthermore, participants who reported 3-13 adverse life events outperformed those who reported a lower (<3) or higher (>13) number of events. Supplementary analyses suggested that this relationship might be due to a small number of extreme values. However, after outlier analyses, a significant linear relationship remained suggesting that a higher number of adverse life events facilitated performance. The results suggest that experiencing a moderate to high number of adverse life events might have beneficial effects on subsequent cardiovascular responses and performance under pressure. Practitioners should therefore consider prior brushes with adversity when identifying athletes who are likely to excel during stressful competition. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Defensive Hostility: Psychosocial Correlates and Associations with Cardiovascular Responses

    DTIC Science & Technology

    1993-04-21

    caffeinated drinks ( coffee , tea, most sodas) for two hours before your scheduled appointment. The completion of the questionnaires should take...high HR reactors were not different from low HR reactors on resting HR, blood pressu re, or serum lipid concentration . A second study replicated...individuals who endorsed suppression of anger items exhibited the greatest cardiovascular responses during Stroop and a math task. Furthermore, Mills

  16. CARDIOVASCULAR RESPONSES OF DIVING AND NONDIVING MAMMALS TO APNEA.

    DTIC Science & Technology

    anesthetized nutria and cats. In the nutria , arterial blood pressure was maintained an average of 182 seconds after profound bradycardia developed despite a...bradycardia was observed. The increase in peripheral resistance during apnea in cats was less than 20% of that found in nutria . Evidence of cardiac...failure was found before bradycardia in the cat, but not in the nutria . It was concluded cardiovascular responses reported for diving mammals could be

  17. Coconut fragrance and cardiovascular response to laboratory stress: results of pilot testing.

    PubMed

    Mezzacappa, Elizabeth Sibolboro; Arumugam, Uma; Chen, Sylvia Yue; Stein, Traci R; Oz, Mehmet; Buckle, Jane

    2010-01-01

    There is preliminary evidence that pleasant fragrances may alter response to stressors in different settings. This pilot study examined the effect of coconut fragrance on cardiovascular response to standard laboratory stressors. While inhaling coconut fragrance (n = 17) or air (n = 15), subjects performed a Stroop color-word task and a mental arithmetic task. Heart rate (HR), heart period variability (HPV) and blood pressure were measured during the 5-minute baseline, the task, and the recovery periods. The results indicated that subjects breathing coconut fragrance had higher HR and lower HPV than those who performed tasks while breathing air. HR response to mental arithmetic seemed to be blunted in the subjects breathing coconut; however, the lack of a difference in HPV seems to indicate that the blunting may be due to decreased sympathetic response, not decreased parasympathetic withdrawal under stress. Blood pressure recovery was slightly enhanced in subjects under coconut fragrance. Thus, the results of this pilot test suggest that coconut fragrance may alter cardiovascular activity both at rest and in response to stressors. Future experimentation should attempt to replicate and extend these findings in larger samples in clinical settings.

  18. Cardiovascular responses to mental activation of social support schemas.

    PubMed

    Creaven, Ann-Marie; Hughes, Brian M

    2012-05-01

    While perceived social support appears to be associated with buffered cardiovascular reactivity to short-term stressors, its impact on cardiovascular recovery is less clear. This relationship might be affected by trait hostility, with hostile individuals benefiting less from social support. However, despite the possibility that support provision might enhance well-being, limited empirical work has manipulated this in a laboratory context. The present study sought to investigate whether mentally activated support provision and support receipt influenced cardiovascular recovery from cognitive stress. Systolic blood pressure, diastolic blood pressure, heart rate, cardiac output, and total peripheral resistance were monitored continuously in a laboratory following exposure to a short-term cognitive stressor. Mixed factorial analyses of variance revealed that inducing thoughts of support provision resulted in elevated post-stressor systolic and diastolic blood pressure responses (p=.03; p=.004) in comparison to thoughts of support receipt or non-supportive social contact. Furthermore, these elevations were most pronounced for individuals high in trait hostility. From this study, support provision when already cognitively and physiologically stressed appears to be deleterious rather than beneficial for cardiovascular function. Moreover, individuals high in trait hostility may be particularly disadvantaged by providing support in everyday life. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Family history of cardiovascular disease is associated with cardiovascular responses to stress in healthy young men and women.

    PubMed

    Wright, Caroline E; O'Donnell, Katie; Brydon, Lena; Wardle, Jane; Steptoe, Andrew

    2007-03-01

    Heightened cardiovascular stress responsivity is associated with cardiovascular disease, but the origins of heightened responsivity are unclear. The present study investigated whether disturbances in cardiovascular responsivity were evident in individuals with a family history of cardiovascular disease risk. Data were collected from 60 women and 31 men with an average age of 21.4 years. Family history of cardiovascular disease risk was defined by the presence of coronary heart disease, hypertension, diabetes or high cholesterol in participants' parents and grandparents; 75 participants had positive, and 16 had negative family histories. Systolic and diastolic blood pressure (BP), heart rate and heart rate variability were measured continuously for 5 min periods at baseline, during two mental stress tasks (Stroop and speech task) and at 10-15 min, 25-30 min and 40-45 min post-stress. Individuals with a positive family history exhibited significantly greater diastolic BP reactivity and poorer systolic and diastolic BP recovery from the stressors in comparison with family history negative individuals. In addition, female participants with a positive family history had heightened heart rate and heart rate variability reactivity to stressors. These effects were independent of baseline cardiovascular activity, body mass index, waist to hip ratio and smoking status. Family history of hypertension alone was not associated with stress responsivity. The findings indicate that a family history of cardiovascular disease risk influences stress responsivity which may in turn contribute to risk of future cardiovascular disorders.

  20. Cardiovascular responses to water drinking: does osmolality play a role?

    PubMed

    Brown, Clive M; Barberini, Luc; Dulloo, Abdul G; Montani, Jean-Pierre

    2005-12-01

    Water drinking activates the autonomic nervous system and induces acute hemodynamic changes. The actual stimulus for these effects is undetermined but might be related to either gastric distension or to osmotic factors. In the present study, we tested whether the cardiovascular responses to water drinking are related to water's relative hypoosmolality. Therefore, we compared the cardiovascular effects of a water drink (7.5 ml/kg body wt) with an identical volume of a physiological (0.9%) saline solution in nine healthy subjects (6 male, 3 female, aged 26 +/- 2 years), while continuously monitoring beat-to-beat blood pressure (finger plethysmography), cardiac intervals (electrocardiography), and cardiac output (thoracic impedance). Total peripheral resistance was calculated as mean blood pressure/cardiac output. Cardiac interval variability (high-frequency power) was assessed by spectral analysis as an index of cardiac vagal tone. Baroreceptor sensitivity was evaluated using the sequence technique. Drinking water, but not saline, decreased heart rate (P = 0.01) and increased total peripheral resistance (P < 0.01), high-frequency cardiac interval variability (P = 0.03), and baroreceptor sensitivity (P = 0.01). Neither water nor saline substantially increased blood pressure. These responses suggest that water drinking simultaneously increases sympathetic vasoconstrictor activity and cardiac vagal tone. That these effects were absent after drinking physiological saline indicate that the cardiovascular responses to water drinking are influenced by its hypoosmotic properties.

  1. Cardiovascular Responses to Skeletal Muscle Stretching: "Stretching" the Truth or a New Exercise Paradigm for Cardiovascular Medicine?

    PubMed

    Kruse, Nicholas T; Scheuermann, Barry W

    2017-08-05

    Stretching is commonly prescribed with the intended purpose of increasing range of motion, enhancing muscular coordination, and preventing prolonged immobilization induced by aging or a sedentary lifestyle. Emerging evidence suggests that acute or long-term stretching exercise may modulate a variety of cardiovascular responses. Specifically, at the onset of stretch, the mechanical deformation of the vascular bed coupled with stimulation of group III muscle afferent fibers initiates a cascade of events resulting in both peripheral vasodilation and a heart rate-driven increase in cardiac output, blood pressure, and muscle blood flow. This potential to increase shear stress and blood flow without the use of excessive muscle energy expenditure may hold important implications for future therapeutic vascular medicine and cardiac health. However, the idea that a cardiovascular component may be involved in human skeletal muscle stretching is relatively new. Therefore, the primary intent of this review is to highlight topics related to skeletal muscle stretching and cardiovascular regulation and function. The current evidence suggests that acute stretching causes a significant macro- and microcirculatory event that alters blood flow and the relationship between oxygen availability and oxygen utilization. These acute vascular changes if performed chronically may result in improved endothelial function, improved arterial blood vessel stiffness, and/or reduced blood pressure. Although several mechanisms have been postulated, an increased nitric oxide bioavailability has been highlighted as one promising candidate for the improvement in vessel function with stretching. Collectively, the evidence provided in this review suggests that stretching acutely or long term may serve as a novel and alternative low intensity therapeutic intervention capable of improving several parameters of vascular function.

  2. Orthostatic intolerance and the cardiovascular response to early postoperative mobilization.

    PubMed

    Bundgaard-Nielsen, M; Jørgensen, C C; Jørgensen, T B; Ruhnau, B; Secher, N H; Kehlet, H

    2009-06-01

    A key element in enhanced postoperative recovery is early mobilization which, however, may be hindered by orthostatic intolerance, that is, an inability to sit or stand because of symptoms of cerebral hypoperfusion as intolerable dizziness, nausea and vomiting, feeling of heat, or blurred vision. We assessed orthostatic tolerance in relation to the postural cardiovascular responses before and shortly after open radical prostatectomy. Orthostatic tolerance and the cardiovascular response to sitting and standing were evaluated on the day before surgery and 6 and 22 h after operation in 16 patients. Non-invasive systolic (SAP) and diastolic arterial pressure (DAP) (Finometer), heart rate, cardiac output (CO, Modelflow), total peripheral resistance (TPR), and central venous oxygen saturation (Scv(O2)) were monitored. Before surgery, no patients had symptoms of orthostatic intolerance. In contrast, 8 (50%) and 2 (12%) patients were orthostatic intolerant at 6 and approximately 22 h after surgery, respectively. Before surgery, SAP, DAP, and TPR increased (P<0.05), whereas CO did not change (P>0.05) and Scv(O2) decreased (P<0.05) upon mobilization. At 6 h after operation, SAP and DAP declined with mobilization (P<0.05) and the arterial pressure response differed from the preoperative response both upon sitting (P<0.05) and standing (P<0.05) due to both impaired TPR and CO. At approximately 22 h, the SAP and DAP responses to mobilization did not differ from the preoperative evaluation (P>0.05). The early postoperative postural cardiovascular response is impaired after radical prostatectomy with a risk of orthostatic intolerance, limiting early postoperative mobilization. The pathogenic mechanisms include both impaired TPR and CO responses.

  3. Serotoninergic Modulation of Basal Cardiovascular Responses and Responses Induced by Isotonic Extracellular Volume Expansion in Rats

    PubMed Central

    Semionatto, Isadora Ferraz; Raminelli, Adrieli Oliveira; Alves, Angelica Cristina; Capitelli, Caroline Santos; Chriguer, Rosangela Soares

    2017-01-01

    Background Isotonic blood volume expansion (BVE) induced alterations of sympathetic and parasympathetic activity in the heart and blood vessels, which can be modulated by serotonergic pathways. Objective To evaluate the effect of saline or serotonergic agonist (DOI) administration in the hypothalamic paraventricular nucleus (PVN) on cardiovascular responses after BVE. Methods We recorded pulsatile blood pressure through the femoral artery to obtain the mean arterial pressure (MAP), systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and the sympathetic-vagal ratio (LF/HF) of Wistar rats before and after they received bilateral microinjections of saline or DOI into the PVN, followed by BVE. Results No significant differences were observed in the values of the studied variables in the different treatments from the control group. However, when animals are treated with DOI followed by BVE there is a significant increase in relation to the BE control group in all the studied variables: MBP (114.42±7.85 vs 101.34±9.17); SBP (147.23±14.31 vs 129.39±10.70); DBP (98.01 ±4.91 vs 87.31±8.61); HR (421.02±43.32 vs 356.35±41.99); and LF/HF ratio (2.32±0.80 vs 0.27±0.32). Discussion The present study showed that the induction of isotonic BVE did not promote alterations in MAP, HR and LF/HF ratio. On the other hand, the injection of DOI into PVN of the hypothalamus followed by isotonic BVE resulted in a significant increase of all variables. Conclusion These results suggest that serotonin induced a neuromodulation in the PVN level, which promotes an inhibition of the baroreflex response to BVE. Therefore, the present study suggests the involvement of the serotonergic system in the modulation of vagal reflex response at PVN in the normotensive rats. PMID:28099586

  4. Altered hormonal regulation and blood flow distribution with cardiovascular deconditioning after short-duration head down bed rest.

    PubMed

    Fischer, D; Arbeille, P; Shoemaker, J K; O'Leary, D D; Hughson, R L

    2007-12-01

    This study tested the hypothesis that cardiovascular and hormonal responses to lower body negative pressure (LBNP) would be altered by 4-h head down bed rest (HDBR) in 11 healthy young men. In post-HDBR testing, three subjects failed to finish the protocol due to presyncopal symptoms, heart rate was increased during LBNP compared with pre-HDBR, mean arterial blood pressure was elevated at 0, -10, and -20 mmHg and reduced at -40 mmHg, central venous pressure (CVP) and cardiac stroke volume were reduced at all levels of LBNP. Plasma concentrations of renin, angiotensin II, and aldosterone were significantly lower after HDBR. Renin and angiotensin II increased in response to LBNP only post-HDBR. There was no effect of HDBR or LBNP on norepinephrine while epinephrine tended to increase at -40 mmHg post-HDBR (P = 0.07). Total blood volume was not significantly reduced. Splanchnic blood flow taken from ultrasound measurement of the portal vein was higher at each level of LBNP post-compared with pre-HDBR. The gain of the cardiopulmonary baroreflex relating changes in total peripheral resistance to CVP was increased after HDBR, but splanchnic vascular resistance was actually reduced. These results are consistent with our hypothesis and suggest that cardiovascular instability following only 4-h HDBR might be related to altered hormonal and/or neural control of regional vascular resistance. Impaired ability to distribute blood away from the splanchnic region was associated with reduced stroke volume, elevated heart rate, and the inability to protect mean arterial pressure.

  5. Cardiovascular regulation by central adrenergic mechanisms and its alteration by hypotensive drugs.

    PubMed

    Haeusler, G

    1975-06-01

    seems that two central adrenergic systems exist with opposing effects on cardiovascular control. These are an excitatory hypothalamic and an inhibitory bulbar adrenergic system. Partial destruction of central adrenergic neurons by intraventricularly injected 6-hydroxydopamine prevents the development of DOCA/NaCl, renal, and neurogenic hypertension and alters the pattern of blood pressure rise in spontaneously hypertensive rats. Impairment of central adrenergic function or imbalance of the two central adrenergic mechanisms may represent a trigger mechanism for the initiation of hypertension.

  6. Cardiovascular and respiratory responses during musical mood induction.

    PubMed

    Etzel, Joset A; Johnsen, Erica L; Dickerson, Julie; Tranel, Daniel; Adolphs, Ralph

    2006-07-01

    Music is used to induce moods in experimental settings as well as for therapeutic purposes. Prior studies suggest that subjects listening to certain types of music experience strong moods and show physiological responses associated with the induced emotions. We hypothesized that cardiovascular and respiratory patterns could discriminate moods induced via music. 18 healthy subjects listened to 12 music clips, four each to induce happiness, sadness, and fear, while cardiovascular and respiratory responses were recorded using an electrocardiogram and chest strain-gauge belt. After each clip subjects completed a questionnaire. Subjects consistently reported experiencing the targeted mood, suggesting successful mood induction. Cardiovascular activity was measured by calculating time domain measures and heart rate changes during each clip. Respiratory activity was measured by total, inspiration, and expiration lengths as well as changes in mean respiration rate during each clip. Evaluation of individuals' patterns and mixed-model analyses were performed. Contrary to expectations, the time domain measures of subjects' cardiovascular responses did not vary significantly between the induced moods, although a heart rate deceleration was found during the sadness inductions and acceleration during the fear inductions. The time domain respiratory measures varied with clip type: the mean breath length was longest for the sad induction, intermediate during fear, and shortest during the happiness induction. However, analysis using normalized least mean squares adaptive filters to measure time correlation indicated that much of this difference may be attributable to entrainment of respiration to characteristics of the music which varied between the stimuli. Our findings point to the difficulty in detecting psychophysiological correlates of mood induction, and further suggest that part of this difficulty may arise from failure to differentiate it from tempo-related contributions

  7. Xenobiotic pulmonary exposure and systemic cardiovascular response via neurological links

    PubMed Central

    Stapleton, Phoebe A.; Abukabda, Alaeddin B.; Hardy, Steven L.

    2015-01-01

    The cardiovascular response to xenobiotic particle exposure has been increasingly studied over the last two decades, producing an extraordinary scope and depth of research findings. With the flourishing of nanotechnology, the term “xenobiotic particles” has expanded to encompass not only air pollution particulate matter (PM) but also anthropogenic particles, such as engineered nanomaterials (ENMs). Historically, the majority of research in these fields has focused on pulmonary exposure and the adverse physiological effects associated with a host inflammatory response or direct particle-tissue interactions. Because these hypotheses can neither account entirely for the deleterious cardiovascular effects of xenobiotic particle exposure nor their time course, the case for substantial neurological involvement is apparent. Indeed, considerable evidence suggests that not only is neural involvement a significant contributor but also a reality that needs to be investigated more thoroughly when assessing xenobiotic particle toxicities. Therefore, the scope of this review is several-fold. First, we provide a brief overview of the major anatomical components of the central and peripheral nervous systems, giving consideration to the potential biologic targets affected by inhaled particles. Second, the autonomic arcs and mechanisms that may be involved are reviewed. Third, the cardiovascular outcomes following neurological responses are discussed. Lastly, unique problems, future risks, and hurdles associated with xenobiotic particle exposure are discussed. A better understanding of these neural issues may facilitate research that in conjunction with existing research, will ultimately prevent the untoward cardiovascular outcomes associated with PM exposures and/or identify safe ENMs for the advancement of human health. PMID:26386111

  8. Cardiovascular Autonomic Response to Amlodipine in Primary Hypertension

    PubMed Central

    Radjab, Youssouf; Aboudrar, Souad; Milouk, Fatima Zahra; Rkain, Hanan; EL Bakkali, Mustapha; Dakka, Taoufiq; Coghlan, Leslie; Benjelloun, Halima

    2012-01-01

    Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was to evaluate both sympathetic and vagal activity responses in patients receiving amlodipine as antihypertensive agent. Patients and Methods. This prospective study included a group of primary hypertensive patients (N = 32, mean age 54.6 ± 7.6 years). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of amlodipine, included deep breathing, hand-grip, and mental stress tests. Statistical analysis was done using the Student's t-test. Results. Cardiovascular autonomic reflexes responses before and after 3 months of amlodipine oral administration were as follows: the mental stress test stimulation method produced a central alpha adrenergic response of 23.9 ± 8.7% versus 11.2 ± 2.0% (P < 0.05), a central beta sympathetic response of 16.7 ± 9.2% versus 10.4 ± 1.3% (P < 0.05), a blood pressure increase in response to hand grip test of 20.5 ± 7.3% versus 10.7 ± 2.4% (P < 0.05), vagal response to deep breathing test was 21.2 ± 6.5% versus 30.8 ± 2.9%, (P < 0.05). Conclusion. The results attest that amlodipine may have an anti-sympathetic effect. PMID:22919515

  9. Simulation of cardiovascular response to acceleration stress following weightless exposure

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Leonard, J. I.

    1983-01-01

    Physiological adjustments taking place during space flight tend to reduce the tolerance of the crew to headward (+Gz) acceleration experienced during the reentry phase of the flight. This reduced tolerance to acceleration stress apparently arises from an adaptation to the microgravity environment of space, including a decrease in the total circulating blood volume. Countermeasures such as anti-g garments have long been known to improve the tolerance to headward g-force, but their effectiveness in space flight has not been fully evaluated. The simulation study presented in this paper is concerned with the response of the cardiovascular system to g-stress following cardiovascular deconditioning, resulting from exposure to weightlessness, or any of its ground-based experimental analogs. The results serve to demonstrate the utility of mathematical modeling and computer simulation for studying the causes of orthostatic intolerance and the remedial measures to lessen it.

  10. Sleep duration and cardiovascular responses to stress in undergraduate men.

    PubMed

    Mezick, Elizabeth J; Matthews, Karen A; Hall, Martica H; Richard Jennings, J; Kamarck, Thomas W

    2014-01-01

    Short sleep has been related to incident cardiovascular disease, but physiological mechanisms accounting for this relationship are largely unknown. This study examines sleep duration and cardiovascular stress responses in 79 healthy, young men. Sleep duration was assessed by wrist actigraphy for seven nights. Participants then completed a series of laboratory stress tasks while heart rate and blood pressure were monitored. Shorter total sleep time was related to a greater reduction in high-frequency heart rate variability during stress tasks, and to prolonged elevations in heart rate and diastolic pressure following tasks. Associations were independent of age, race, body mass index, caffeine intake, and smoking status. In sum, healthy young men with shorter actigraphy-assessed sleep exhibit less cardiac vagal activity, and poorer heart rate and diastolic blood pressure recovery, upon encountering stressful stimuli, than those with longer sleep.

  11. Exaggerated Exercise Blood Pressure Response and Future Cardiovascular Disease.

    PubMed

    Tzemos, Nikolaos; Lim, Pitt O; Mackenzie, Isla S; MacDonald, Thomas M

    2015-11-01

    Exaggerated blood pressure (BP) response to exercise predicts future hypertension. However, there is considerable lack of understanding regarding the mechanism of how this abnormal response is generated, and how it relates to the future establishment of cardiovascular disease. The authors studied 82 healthy male volunteers without cardiovascular risk factors. The participants were categorized into two age-matched groups depending on their exercise systolic BP (ExSBP) rise after 3 minutes of exercise using a submaximal step test: exaggerated ExSBP group (hyper-responders [peak SBP ≥ 180 mm Hg]) and low ExSBP responder group (hypo-responders [peak SBP <180 mm Hg]). Forearm venous occlusion plethysmography and intra-arterial infusions of acetylcholine (ACh), N(G)-monomethyl-L-arginine (L-NMMA), sodium nitroprusside (SNP), and norepinephrine (NE) were used to assess vascular reactivity. Proximal aortic compliance was assessed with ultrasound, and neurohormonal blood sampling was performed at rest and during peak exercise. The hyper-responder group exhibited a significantly lower increase in forearm blood flow (FBF) with ACh compared with the hypo-responder group (ΔFBF 215% [14] vs 332.3% [28], mean [standard error of the mean]; P<.001), as well as decreased proximal aortic compliance. The vasoconstrictive response to L-NMMA was significantly impaired in the hyper-responder group in comparison to the hypo-responder group (ΔFBF -40.2% [1.6] vs -50.2% [2.6]; P<.05). In contrast, the vascular response to SNP and NE were comparable in both groups. Peak exercise plasma angiotensin II levels were significantly higher in the hyper-responder group (31 [1] vs 23 [2] pg/mL, P=.01). An exaggerated BP response to exercise is related to endothelial dysfunction, decreased proximal aortic compliance, and increased exercise-related neurohormonal activation, the constellation of which may explain future cardiovascular disease.

  12. Cardiovascular

    NASA Image and Video Library

    Overview of Cardiovascular research which addresses risks of space flight, including adaptive changes to the cephalad fluid shift (such as reduced circulating blood volume), potential for heart rhy...

  13. Dose-and time-dependent cardiovascular responses induced by ethanol

    SciTech Connect

    Brackett, D.J.; Gauvin, D.V.; Lerner, M.R.; Lander, T.J.; Holloway, F.A.; Wilson, M.F. )

    1991-03-11

    A literature survey has revealed that a dose-response relationship between ethanol (ETOH) and serial measurements of cardiovascular parameters that include cardiac output (CO) and systemic vascular resistance (SVR) has not been established in conscious animals. The available literature in this area is controversial regarding the responses of these two parameters that control tissue blood flow. In this study, rats were instrumented for conscious cardiovascular measurements and blood sampling. Rats were monitored for 4 hrs after intragastric ETOH at 2, 4, or 6 g/kg or water. Samples for blood alcohol concentrations were taken at every measurement point and achieved peak concentrations of 63 {plus minus} 4, 103 {plus minus} 6, and 221 {plus minus} 17 mg/dl. Dose- and time-dependency were documented for decreased CO, blood pressure, respiration rate, stroke volume, and central venous pressure, and increased SVR, heart rate, and blood glucose concentrations. Thermoregulatory disturbances were observed at all doses. Blood hematocrit and lactate concentrations were unchanged. In conscious rats ethanol induced significant dose- and time-dependent hemodynamic alterations, including marked CO reduction and peripheral vasoconstriction, suggesting the potential of compromised tissue perfusion. Data also indicate that increased sympathoadrenal activity following ETOH administration may be a significant mediator of these responses. These data suggest: (1) when evaluating the physiological effects of drugs, a complete battery of cardiovascular and physiological measurements need to be assessed, and (2) when measured, these indices suggest a greater degree of compromise by ETOH than previously reported.

  14. Success importance and urge magnitude as determinants of cardiovascular response to a behavioral restraint challenge.

    PubMed

    Agtarap, Stephanie D; Wright, Rex A; Mlynski, Christopher; Hammad, Rawan; Blackledge, Sabrina

    2016-04-01

    Decades of research have investigated a conceptual analysis concerned with determinants and cardiovascular correlates of effort in people confronted with performance challenges, that is, opportunities to alter some course of events by acting. One suggestion is that effort and associated cardiovascular responses should be determined jointly by the difficulty of meeting a challenge and the importance of doing so. The present experiment tested this in a context involving behavioral restraint, that is, effortful resistance against a behavioral impulse or urge. Participants were presented a mildly evocative violent film clip (restraint difficulty low) or a strongly evocative violent film clip (restraint difficulty high) with instructions to refrain from showing any facial response. Success was made more or less important through coordinated manipulations of outcome expectancy, ego-involvement and social evaluation. As expected, SBP responses assessed during the work period were proportional to clip evocativeness - i.e., the difficulty of the restraint challenge - when importance was high, but low regardless of clip evocativeness when importance was low. Findings conceptually replicate previous cardiovascular results and support extension of the guiding analysis to the behavioral restraint realm.

  15. Here we go again: bullying history and cardiovascular responses to social exclusion.

    PubMed

    Newman, Matthew L

    2014-06-22

    Previous research suggests that social exclusion-both acute and chronic-may be associated with a pattern of blunted cardiovascular responding. But it is unknown to what extent acute and chronic exclusion interact. That is, what happens when victims of long-term social rejection encounter an instance of exclusion later in life? The goal of the present study was to test whether prior experience being bullied would alter cardiovascular responses to an acute experience of social exclusion. Participants took part in a short online chat, during which they were either included or excluded from the conversation. Consistent with hypotheses, all participants showed an increase in sympathetic activity in the exclusion condition, but this response was significantly blunted among those with more chronic history of bullying victimization. No differences were observed for parasympathetic activity. This pattern suggests that a history of chronic victimization magnifies the cardiovascular "blunting" shown previously among victims of ostracism. This line of work suggests that bullying victims may develop regulatory mechanisms in response to social threats, and this may ultimately provide valuable information for helping victims become more resilient.

  16. Gravitational effects on human cardiovascular responses to isometric muscle contractions

    NASA Astrophysics Data System (ADS)

    Bonde-Petersen, Flemmig; Suzuki, Yoji; Sadamoto, Tomoko

    Isometric exercise induces profound cardiovascular adaptations increasing mean arterial pressure and heart rate. We investigated effects of simulated +Gz and -Gz respectively on the central and peripheral cardiovascular system. Sustained handgrip exercise was performed at 40% of maximum for 2 minutes in five subjects. This maneuver increased mean arterial pressure by 40-45 mm Hg both during head out water immersion which simulates weightlessness, as well as bedrest during -25, 0, and +25 degrees tilt from the horizontal. Lower body negative pressure (-60 mm Hg for 10 min) attenuated the response to handgrip exercise to 30 mm Hg. It also increased the heart rate minimally by about 20 beats per minute while the water immersion, as well as head up, head down and horizontal bedrest showed increments of about 50 beats per min. It was concluded that the response to isometric contraction is mediated through the high pressure baroreceptors, because similar responses were seen during stresses producing a wide variation in central venous pressure. During lower body negative pressure the increased sympathetic nervous activity itself increased resting heart rate and mean arterial pressure. The responses to static exercise were, therefore, weaker.

  17. Increased Klk9 Urinary Excretion Is Associated to Hypertension-Induced Cardiovascular Damage and Renal Alterations

    PubMed Central

    Blázquez-Medela, Ana M.; García-Sánchez, Omar; Quirós, Yaremi; Blanco-Gozalo, Victor; Prieto-García, Laura; Sancho-Martínez, Sandra M.; Romero, Miguel; Duarte, Juan M.; López-Hernández, Francisco J.; López-Novoa, José M.; Martínez-Salgado, Carlos

    2015-01-01

    Abstract Early detection of hypertensive end-organ damage and secondary diseases are key determinants of cardiovascular prognosis in patients suffering from arterial hypertension. Presently, there are no biomarkers for the detection of hypertensive target organ damage, most outstandingly including blood vessels, the heart, and the kidneys. We aimed to validate the usefulness of the urinary excretion of the serine protease kallikrein-related peptidase 9 (KLK9) as a biomarker of hypertension-induced target organ damage. Urinary, plasma, and renal tissue levels of KLK9 were measured by the Western blot in different rat models of hypertension, including angiotensin-II infusion, DOCA-salt, L-NAME administration, and spontaneous hypertension. Urinary levels were associated to cardiovascular and renal injury, assessed by histopathology. The origin of urinary KLK9 was investigated through in situ renal perfusion experiments. The urinary excretion of KLK9 is increased in different experimental models of hypertension in rats. The ACE inhibitor trandolapril significantly reduced arterial pressure and the urinary level of KLK9. Hypertension did not increase kidney, heart, liver, lung, or plasma KLK9 levels. Hypertension-induced increased urinary excretion of KLK9 results from specific alterations in its tubular reabsorption, even in the absence of overt nephropathy. KLK9 urinary excretion strongly correlates with cardiac hypertrophy and aortic wall thickening. KLK9 appears in the urine in the presence of hypertension as a result of subtle renal handling alterations. Urinary KLK9 might be potentially used as an indicator of hypertensive cardiac and vascular damage. PMID:26469898

  18. Cardiovascular responses to Bothrops alternatus (Urutu) snake venom in anesthetized dogs.

    PubMed

    Dias, Lourdes; Rodrigues, Mariana A P; Smaal, Adriana; Rennó, André L; Mello, Sueli M; Moreno, Heitor; Hyslop, Stephen

    2012-09-01

    The cardiovascular responses to Bothrops alternatus snake venom in anesthetized dogs were investigated. Venom (0.3 mg/kg, i.v.) markedly decreased arterial blood pressure, coronary perfusion pressure, and cardiac output (CO) after 5 min, with progressive recovery of the first two parameters to pre-venom levels after 3 h; CO showed little recovery. There was an abrupt, sustained decrease in left and right ventricular systolic work and stroke volume but no significant changes in heart rate, electrocardiogram, and pulmonary hemodynamics; systemic vascular resistance increased from 1 h onwards. A venom dose of 1 mg/kg produced more pronounced cardiovascular alterations, with a progressive decrease to death. There were no significant changes in blood gas (pO(2), pCO(2), HCO(3), SBC, and SBE) and metabolic (pH, lactate, glucose, creatine kinase activity, Na(+), and K(+)) parameters, although there was a transitory increase in plasma lactate dehydrogenase 2 min after the lower venom dose. There were no cardiac histological alterations, but microaneurysms and epithelial desquamation were seen in renal tubules. Circulating venom concentrations (determined by ELISA) decreased rapidly after administration, but venom was still detectable after 4 h. These results show that in dogs, B. alternatus venom produces marked hypotension and a direct cardiac action, with few metabolic alterations.

  19. Cardiovascular responses to glucagon - Physiologic measurement by external recordings.

    NASA Technical Reports Server (NTRS)

    Byrne, M. J.; Pigott, V.; Spodick, D. H.

    1972-01-01

    Assessment by noninvasive polygraphic techniques of the cardiovascular responses of normal subjects to intravenous injections of glucagon and glucagon diluent. A blinding procedure which eliminated observer bias was used during the reading of tracings. Analysis of group results showed that glucagon provoked uniformly significant changes, including increase in heart rate, blood pressure, pressure-rate product, and ejection time index, and decrease in prejection period, mechanical and electromechanical systole, left ventricular ejection time, and the ratio PEP/LVET. The principal results correlated well with those of previous studies of the hemodynamic effects of glucagon.

  20. Cardiovascular responses to heat stress in chronic heart failure

    PubMed Central

    Cui, Jian; Sinoway, Lawrence I.

    2014-01-01

    Clinical reports have suggested that patients with heart diseases may be particularly vulnerable to heat injury. This review examines the effects of heat stress on cardiovascular and autonomic functions in patients with chronic heart failure (CHF). Laboratory investigations have shown that cutaneous vasodilator responses to heating are impaired in patients, whereas activation of skin sympathetic nerve activation is not attenuated in CHF as compared to controls. Attenuated cutaneous vasodilation may increase the risk of a heat related illness when CHF subjects are exposed to hyperthermic conditions. PMID:24599558

  1. Cardiovascular Responses to Caffeine by Gender and Pubertal Stage

    PubMed Central

    Ziegler, Amanda M.; Graczyk, Adam; Bendlin, Ashley; Sion, Teresa; Vattana, Karina

    2014-01-01

    BACKGROUND: Caffeine use is on the rise among children and adolescents. Previous studies from our laboratory reported gender differences in the effects of caffeine in adolescents. The purpose of this study was to test the hypotheses that gender differences in cardiovascular responses to caffeine emerge after puberty and that cardiovascular responses to caffeine differ across the phases of the menstrual cycle. METHODS: To test these hypotheses, we examined heart rate and blood pressure before and after administration of placebo and 2 doses of caffeine (1 and 2 mg/kg) in prepubertal (8- to 9-year-olds; n = 52) and postpubertal (15- to 17-year-olds; n = 49) boys (n = 54) and girls (n = 47) by using a double-blind, placebo-controlled, dose-response design. RESULTS: There was an interaction between gender and caffeine dose, with boys having a greater response to caffeine than girls. In addition, we found interactions between pubertal phase, gender, and caffeine dose, with gender differences present in postpubertal, but not in prepubertal, participants. Finally, we found differences in responses to caffeine across the menstrual cycle in post-pubertal girls, with decreases in heart rate greater in the midluteal phase and blood pressure increases greater in the midfollicular phase of the menstrual cycle. CONCLUSIONS: These data suggest that gender differences in response to caffeine emerge after puberty. Future research will determine the extent to which these gender differences are mediated by physiological factors, such as steroid hormones, or psychosocial factors, such as more autonomy and control over beverage purchases. PMID:24935999

  2. Prior Exercise Alters Responses to Hemorrhage

    DTIC Science & Technology

    2010-07-01

    for the swine in our laboratory (4, 17). Plasma renin activ- ity (PRA), aldosterone, cortisol, and adrenocorticotropic hormone (ACTH) were measured...could aid in their care. Exercise acutely reduces blood volume, increases plasma lactate concentrations, and alters the hormonal /immunologic milieu...concentration was measured enzymatically with a commercial kit (Sigma Chemical Co, St Louis, Mo). Hormone concentrations were measured with tech- niques validated

  3. Dose Response Effects of Hypertonic Saline and Dextran on Cardiovascular Responses in Sheep

    DTIC Science & Technology

    1995-02-01

    137-144, 1995 DOSE RESPONSE EFFECTS OF HYPERTONIC SALINE AND DEXTRAN ON CARDIOVASCULAR RESPONSES AND PLASMA VOLUME EXPANSION IN SHEEP Michael A...addressed the dose - response effects of HS or D-70 solutions or their possible synergistic combinations to evaluate optimal concentrations of the HS and D...205-217, 1989. 13. Halvorsen L, Günther RA, Dubick MA, Holcroft JW: Dose response characteristics of hypertonic saline dextran solution. J Trauma

  4. Cardiovascular responses to intrathecal administration of endomorphins in anesthetized rats.

    PubMed

    Wang, Chang-Lin; Yu, Ye; Lai, Lu-Hao; Cui, Yun; Wang, Xiang; Wang, Rui

    2007-04-01

    Endomorphins (EMs), the endogenous, potent and selective mu-opioid receptor agonists, have been shown to decrease systemic arterial pressure (SAP) in rats after intravenous (i.v.) administration. In the present study, cardiovascular responses to intrathecal (i.t.) injection of EMs were investigated in urethane-anesthetized rats. It is noteworthy that EMs elicited decreases in SAP and heart rate (HR) in a dose-dependent manner; 10-300nmol/kg were injected intrathecally. Furthermore, these vasodepressor and bradycardic effects were significantly antagonized by naloxone (0.5mg/kg, i.t.). Interestingly, i.t. (5mg/kg) or i.v. (50mg/kg) administrations of N(omega)-nitro-l-arginine methylester (l-NAME) attenuated the vasodepressor and bradycardic effects. Moreover, pretreatment of the rats with muscarinic receptor antagonist atropine (2mg/kg, i.v.) and alpha-adrenoceptor antagonist phentolamine (1mg/kg, i.v.) significantly reduced the vasodepressor effects of EMs. Nevertheless, pretreatment with beta-adrenoceptor antagonist propranolol (2mg/kg, i.v.) could only block the bradycardia effects induced by EMs, but had no significant effects on the hypotension. In summary, all the results suggested that i.t. administration of EMs decreased SAP and HR which were possibly mediated by the activation of opioid receptors in the rat spinal cord. In addition, nitric oxide (NO) release in both the spinal cord and in peripheral tissues might regulate the cardiovascular activities of EMs, and the muscarinic receptor and adrenoceptor played an important role in the regulation of the cardiovascular responses to i.t. administration of EMs.

  5. Role of autonomic reflex arcs in cardiovascular responses to air pollution exposure.

    PubMed

    Perez, Christina M; Hazari, Mehdi S; Farraj, Aimen K

    2015-01-01

    The body responds to environmental stressors by triggering autonomic reflexes in the pulmonary receptors, baroreceptors, and chemoreceptors to maintain homeostasis. Numerous studies have shown that exposure to various gases and airborne particles can alter the functional outcome of these reflexes, particularly with respect to the cardiovascular system. Modulation of autonomic neural input to the heart and vasculature following direct activation of sensory nerves in the respiratory system, elicitation of oxidative stress and inflammation, or through other mechanisms is one of the primary ways that exposure to air pollution affects normal cardiovascular function. Any homeostatic process that utilizes the autonomic nervous system to regulate organ function might be affected. Thus, air pollution and other inhaled environmental irritants have the potential to alter both local airway function and baro- and chemoreflex responses, which modulate autonomic control of blood pressure and detect concentrations of key gases in the body. While each of these reflex pathways causes distinct responses, the systems are heavily integrated and communicate through overlapping regions of the brainstem to cause global effects. This short review summarizes the function of major pulmonary sensory receptors, baroreceptors, and carotid body chemoreceptors and discusses the impacts of air pollution exposure on these systems.

  6. Exposure to Maternal Gestational Diabetes Is Associated With Higher Cardiovascular Responses to Stress in Adolescent Indians

    PubMed Central

    Veena, Sargoor R.; Jones, Alexander; Srinivasan, Krishnamachari; Osmond, Clive; Karat, Samuel C.; Kurpad, Anura V.; Fall, Caroline H. D.

    2015-01-01

    Context: Altered endocrinal and autonomic nervous system responses to stress may link impaired intra-uterine growth with later cardiovascular disease. Objective: To test the hypothesis that offspring of gestational diabetic mothers (OGDM) have high cortisol and cardiosympathetic responses during the Trier Social Stress Test for Children (TSST-C). Design: Adolescents from a birth cohort in India (n = 213; mean age, 13.5 y), including 26 OGDM, 22 offspring of diabetic fathers (ODF), and 165 offspring of nondiabetic parents (controls) completed 5 minutes each of public speaking and mental arithmetic tasks in front of two unfamiliar “evaluators” (TSST-C). Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Heart rate, blood pressure (BP), stroke volume, cardiac output, and total peripheral resistance were measured continuously at baseline, during the TSST-C, and for 10 minutes after the test using a finger cuff; the beat-to-beat values were averaged for these periods. Results: Cortisol and cardiosympathetic parameters increased from baseline during stress (P < .001). OGDM had greater systolic BP (mean difference, 5.6 mm Hg), cardiac output (0.5 L/min), and stroke volume (4.0 mL) increases and a lower total peripheral resistance rise (125 dyn · s/cm5) than controls during stress. ODF had greater systolic BP responses than controls (difference, 4.1 mm Hg); there was no difference in other cardiosympathetic parameters. Cortisol responses were similar in all three groups. Conclusions: Maternal diabetes during pregnancy is associated with higher cardiosympathetic stress responses in the offspring, which may contribute to their higher cardiovascular disease risk. Further research may confirm stress-response programming as a predictor of cardiovascular risk in OGDM. PMID:25478935

  7. Exposure to maternal gestational diabetes is associated with higher cardiovascular responses to stress in adolescent indians.

    PubMed

    Krishnaveni, Ghattu V; Veena, Sargoor R; Jones, Alexander; Srinivasan, Krishnamachari; Osmond, Clive; Karat, Samuel C; Kurpad, Anura V; Fall, Caroline H D

    2015-03-01

    Altered endocrinal and autonomic nervous system responses to stress may link impaired intra-uterine growth with later cardiovascular disease. To test the hypothesis that offspring of gestational diabetic mothers (OGDM) have high cortisol and cardiosympathetic responses during the Trier Social Stress Test for Children (TSST-C). Adolescents from a birth cohort in India (n = 213; mean age, 13.5 y), including 26 OGDM, 22 offspring of diabetic fathers (ODF), and 165 offspring of nondiabetic parents (controls) completed 5 minutes each of public speaking and mental arithmetic tasks in front of two unfamiliar "evaluators" (TSST-C). Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Heart rate, blood pressure (BP), stroke volume, cardiac output, and total peripheral resistance were measured continuously at baseline, during the TSST-C, and for 10 minutes after the test using a finger cuff; the beat-to-beat values were averaged for these periods. Cortisol and cardiosympathetic parameters increased from baseline during stress (P < .001). OGDM had greater systolic BP (mean difference, 5.6 mm Hg), cardiac output (0.5 L/min), and stroke volume (4.0 mL) increases and a lower total peripheral resistance rise (125 dyn · s/cm(5)) than controls during stress. ODF had greater systolic BP responses than controls (difference, 4.1 mm Hg); there was no difference in other cardiosympathetic parameters. Cortisol responses were similar in all three groups. Maternal diabetes during pregnancy is associated with higher cardiosympathetic stress responses in the offspring, which may contribute to their higher cardiovascular disease risk. Further research may confirm stress-response programming as a predictor of cardiovascular risk in OGDM.

  8. Oral Cannabidiol does not Alter the Subjective, Reinforcing or Cardiovascular Effects of Smoked Cannabis

    PubMed Central

    Haney, Margaret; Malcolm, Robert J; Babalonis, Shanna; Nuzzo, Paul A; Cooper, Ziva D; Bedi, Gillinder; Gray, Kevin M; McRae-Clark, Aimee; Lofwall, Michelle R; Sparenborg, Steven; Walsh, Sharon L

    2016-01-01

    Cannabidiol (CBD), a constituent of cannabis with few psychoactive effects, has been reported in some studies to attenuate certain aspects of Δ9-tetrahydrocannabinol (THC) intoxication. However, most studies have tested only one dose of CBD in combination with one dose of oral THC, making it difficult to assess the nature of this interaction. Further, the effect of oral CBD on smoked cannabis administration is unknown. The objective of this multi-site, randomized, double-blind, within-subject laboratory study was to assess the influence of CBD (0, 200, 400, 800 mg, p.o.) pretreatment on the reinforcing, subjective, cognitive, and physiological effects of smoked cannabis (0.01 (inactive), 5.30–5.80% THC). Non-treatment-seeking, healthy cannabis smokers (n=31; 17M, 14 F) completed eight outpatient sessions. CBD was administered 90 min prior to cannabis administration. The behavioral and cardiovascular effects of cannabis were measured at baseline and repeatedly throughout the session. A subset of participants (n=8) completed an additional session to measure plasma CBD concentrations after administration of the highest CBD dose (800 mg). Under placebo CBD conditions, active cannabis (1) was self-administered by significantly more participants than placebo cannabis and (2) produced significant, time-dependent increases in ratings of ‘High', ‘Good Effect', ratings of the cannabis cigarette (eg, strength, liking), and heart rate relative to inactive cannabis. CBD, which alone produced no significant psychoactive or cardiovascular effects, did not significantly alter any of these outcomes. Cannabis self-administration, subjective effects, and cannabis ratings did not vary as a function of CBD dose relative to placebo capsules. These findings suggest that oral CBD does not reduce the reinforcing, physiological, or positive subjective effects of smoked cannabis. PMID:26708108

  9. Oral Cannabidiol does not Alter the Subjective, Reinforcing or Cardiovascular Effects of Smoked Cannabis.

    PubMed

    Haney, Margaret; Malcolm, Robert J; Babalonis, Shanna; Nuzzo, Paul A; Cooper, Ziva D; Bedi, Gillinder; Gray, Kevin M; McRae-Clark, Aimee; Lofwall, Michelle R; Sparenborg, Steven; Walsh, Sharon L

    2016-07-01

    Cannabidiol (CBD), a constituent of cannabis with few psychoactive effects, has been reported in some studies to attenuate certain aspects of Δ(9)-tetrahydrocannabinol (THC) intoxication. However, most studies have tested only one dose of CBD in combination with one dose of oral THC, making it difficult to assess the nature of this interaction. Further, the effect of oral CBD on smoked cannabis administration is unknown. The objective of this multi-site, randomized, double-blind, within-subject laboratory study was to assess the influence of CBD (0, 200, 400, 800 mg, p.o.) pretreatment on the reinforcing, subjective, cognitive, and physiological effects of smoked cannabis (0.01 (inactive), 5.30-5.80% THC). Non-treatment-seeking, healthy cannabis smokers (n=31; 17M, 14 F) completed eight outpatient sessions. CBD was administered 90 min prior to cannabis administration. The behavioral and cardiovascular effects of cannabis were measured at baseline and repeatedly throughout the session. A subset of participants (n=8) completed an additional session to measure plasma CBD concentrations after administration of the highest CBD dose (800 mg). Under placebo CBD conditions, active cannabis (1) was self-administered by significantly more participants than placebo cannabis and (2) produced significant, time-dependent increases in ratings of 'High', 'Good Effect', ratings of the cannabis cigarette (eg, strength, liking), and heart rate relative to inactive cannabis. CBD, which alone produced no significant psychoactive or cardiovascular effects, did not significantly alter any of these outcomes. Cannabis self-administration, subjective effects, and cannabis ratings did not vary as a function of CBD dose relative to placebo capsules. These findings suggest that oral CBD does not reduce the reinforcing, physiological, or positive subjective effects of smoked cannabis.

  10. Altered cardiovascular autonomic regulation in overweight children engaged in regular physical activity.

    PubMed

    Lucini, Daniela; de Giacomi, Gaia; Tosi, Fabio; Malacarne, Mara; Respizzi, Stefano; Pagani, Massimo

    2013-03-01

    Overweight (OW) and obesity in children are important forerunners of cardiovascular risk, possibly through autonomic nervous system (ANS) dysregulation, while physical exercise exerts a beneficial influence. In this observational study we hypothesise that OW might influence ANS profile even in a population performing high volume of supervised exercise. We study 103 young soccer players, homogeneous in terms of gender (all male), cultural background, school, age (11.2 ± 1 years) and exercise routine, since they all belong to the same soccer club, thus guaranteeing equality of supervised training and similar levels of competitiveness. ANS is evaluated by autoregressive spectral analysis of heart rate and systolic arterial pressure (SAP) variabilities. We estimate also the accumulated weekly Metabolic Equivalents and time spent in sedentary activities. We subdivide the entire population in two subgroups (normal weight and OW) based on the International Obesity Task Force criteria. In OW soccer players (10.7% of total group) we observe an altered profile of autonomic cardiovascular regulation, characterised by higher values of SAP (113 ± 4 vs 100 ± 1 mm Hg, 39.7 ± 3 vs 66.2 ± 10%), higher Low Frequency variability power of SAP (an index of vasomotor sympathetic regulation) (12 ± 3 vs 4.5 mm Hg(2)) and smaller spontaneous baroreflex gain (an index of cardiac vagal regulation) (19 ± 3 vs 33 ± 3 ms/mm Hg) (all (p < 0.02)). Moreover Correlation analysis on the entire study population shows a significant link between anthropometric and autonomic indices. These data show that OW is associated to a clear autonomic impairment even in children subjected to an intense aerobic training.

  11. Hormonal and cardiovascular responses to DDAVP in man.

    PubMed

    Williams, T D; Lightman, S L; Leadbeater, M J

    1986-01-01

    Hormonal and cardiovascular responses to 1-desamino-8-D-arginine vasopressin (DDAVP) were investigated in six normal adult volunteers. After overnight fluid deprivation, an intravenous injection of either DDAVP (0.4 microgram/kg) or the same volume of normal saline was administered. One hour later an intravenous infusion of hypertonic saline was commenced and continued over two hours. Five minutes following the DDAVP injection, facial flushing, a fall in diastolic blood pressure by an average of 13% and a rise in pulse rate by an average of 18% were observed. There was a significant increase in plasma renin activity and plasma cortisol concentration, but no significant changes were observed in plasma concentrations of LH, FSH, TSH, prolactin or GH. Following osmotic stimulation by hypertonic saline plasma AVP rose to the same extent in both the DDAVP and control studies. DDAVP (0.4 microgram/kg) was also administered to five subjects with cranial diabetes insipidus. Again facial flushing, increased facial temperature, a fall in diastolic pressure and a rise in heart rate were all observed, suggesting that DDAVP exerts its cardiovascular actions by a mechanism other than antagonism of circulating endogenous AVP.

  12. Two anomalous cardiovascular responses to active standing in essential hypertension.

    PubMed

    Bettencourt, M Joaquina; Pinto, Basílio Gomes; de Oliveira, E Infante; Silva-Carvalho, L

    2008-05-01

    In a previous work we studied, non-invasively, autonomic nervous system control of circulation in healthy subjects, observing the hemodynamic reaction to active standing. We now propose to extend this analysis to essential hypertension (EH), investigating possible autonomic dysfunction. The cardiovascular response to postural change from the supine position to active standing of 48 EH patients, of both sexes, with and without medication, was compared with that obtained for healthy subjects. We evaluated arterial systolic (SBP) and diastolic (DBP) blood pressure, stroke volume (SV), inotropic index (INOI), total vascular resistance (TVR), cardiac work (W), stroke work (SW), arterial compliance (AC) and heart rate (HR), using the entirely non-invasive BoMed NCCOM3 thoracic electrical bioimpedance monitor and sphygmomanometry. We found two patient groups characterized by different linear relationships between values of cardiovascular variables in active standing and in supine positions. Except for HR, in both groups these regression lines differed from normal. Compared to the supine position, in active standing, one group (EH-I) presented increased TVR, diminished SV, INOI, W, SW, and AC, and normal HR; the other group (EH-II) presented diminished TVR and HR and increased SV, INOI, W, SW and AC. The two patient groups could be separated on the basis of their age, but not on the basis of their systolic, diastolic and mean arterial blood pressures, gender or medication. The younger patient group (EH-I) included 28 subjects aged 24 to 69 years (50+/-10), of whom 11 were unmedicated, and the older patient group (EH-II) included 20 subjects aged 35 to 75 years (62+/-11), of whom 7 were unmedicated. Our results show a depressed response in postural change for older patients, which in the autonomic control of circulation expresses carotid baroreflex impairment, and conversely an enhanced response for younger patients, which can be caused by a maladjustment of the influence

  13. Essential Hypertension: Cardiovascular Response to Breath Hold Combined with Exercise.

    PubMed

    Hoffmann, U; Urban, P; Koschate, J; Drescher, U; Pfister, R; Michels, G

    2015-07-01

    Essential hypertension (EH) is a widespread disease and might be prevalent in apnea divers and master athletes. Little is known about the influence of EH and the antihypertensive drugs (AHD) on cardiovascular reactions to combined breath hold (BH) and exercise. In this pilot study, healthy divers (HCON) were compared with treated hypertensive divers with regard to heart rate (HR) and mean blood-pressure (MAP) responses to BH, exercise and the combination of both. Ten subjects with EH and ten healthy divers were tested. 3 different 20 s stimuli were applied: BH combined with 30 W or 150 W and 150 W without BH. The time-charts during the stress intervals and during recovery were compared. Subjects treated with an angiotensin-converting enzyme (ACE) inhibitor showed higher changes for MAP values if breath hold was performed. HR responses were obviously changed if a β-blocker was part of the medication. One subject showed extreme MAP responses to all stimuli and conspicuous HR if BH was involved. The modulation of HR-/MAP-response in EH subjects depends on the mechanisms of antihypertensive agents. The combination of an ACE inhibitor and a β-blocker may give the best protection. It is recommended to include short apnea tests in the fitness-to-dive examination to individually predict potential endangerment.

  14. Cardiovascular Alterations After Injection of 2% Lidocaine With Norepinephrine 1:50,000 (Xylestesin) in Rats

    PubMed Central

    Faraco, Fatima Neves; Armonia, Paschoal Laercio; Malamed, Stanley F

    2007-01-01

    The purpose of the present study is to determine the cardiovascular effects produced by intravascular injection of 2% lidocaine with 20 μg/mL of norepinephrine on systolic, diastolic, and mean arterial pressures and heart rate of rats at the following times: control period, during the injection (first 15 seconds), during the first minute, and at the end of 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after drug administration. The study was performed on 13 male Wistar rats with weights between 200 grams and 220 grams that were awake during the recording of these parameters. The dose administered was proportional to 1 cartridge of local anesthetic (1.8 mL) in an average-size human, which is equivalent to 0.51 mg/kg of lidocaine hydrochloride and 0.51 μg/kg of norepinephrine hydrochloride. The average time of injection was 15.7 seconds. The results of this study showed significant increases in systolic, diastolic, and mean arterial pressure and a noticeable decrease in heart rate. The greatest variation occurred in the systolic blood pressure. The greatest alterations occurred during injection and within the first minute following administration of the anesthetic solution. We would anticipate these changes in the parameters analyzed to be clinically significant. Thus, dentists using 2% lidocaine with norepinephrine 20 μg/mL should be very careful to avoid intravascular injection. PMID:17579502

  15. Cardiovascular alterations after injection of 2% lidocaine with norepinephrine 1:50,000 (xylestesin) in rats.

    PubMed

    Faraco, Fatima Neves; Armonia, Paschoal Laercio; Malamed, Stanley F

    2007-01-01

    The purpose of the present study is to determine the cardiovascular effects produced by intravascular injection of 2% lidocaine with 20 microg/mL of norepinephrine on systolic, diastolic, and mean arterial pressures and heart rate of rats at the following times: control period, during the injection (first 15 seconds), during the first minute, and at the end of 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after drug administration. The study was performed on 13 male Wistar rats with weights between 200 grams and 220 grams that were awake during the recording of these parameters. The dose administered was proportional to 1 cartridge of local anesthetic (1.8 mL) in an average-size human, which is equivalent to 0.51 mg/kg of lidocaine hydrochloride and 0.51 microg/kg of norepinephrine hydrochloride. The average time of injection was 15.7 seconds. The results of this study showed significant increases in systolic, diastolic, and mean arterial pressure and a noticeable decrease in heart rate. The greatest variation occurred in the systolic blood pressure. The greatest alterations occurred during injection and within the first minute following administration of the anesthetic solution. We would anticipate these changes in the parameters analyzed to be clinically significant. Thus, dentists using 2% lidocaine with norepinephrine 20 mug/mL should be very careful to avoid intravascular injection.

  16. Kalpaamruthaa ameliorates mitochondrial and metabolic alterations in diabetes mellitus induced cardiovascular damage.

    PubMed

    Latha, Raja; Shanthi, Palanivelu; Sachdanandam, Panchanadham

    2014-12-01

    Efficacy of Kalpaamruthaa on the activities of lipid and carbohydrate metabolic enzymes, electron transport chain complexes and mitochondrial ATPases were studied in heart and liver of experimental rats. Cardiovascular damage (CVD) was developed in 8 weeks after type 2 diabetes mellitus induction with high fat diet (2 weeks) and low dose of streptozotocin (2 × 35 mg/kg b.w. i.p. in 24 hr interval). In CVD-induced rats, the activities of total lipase, cholesterol ester hydrolase and cholesterol ester synthetase were increased, while lipoprotein lipase and lecithin-cholesterol acyltransferase activities were decreased. The activities of lipid-metabolizing enzymes were altered by Kalpaamruthaa in CVD-induced rats towards normal. Kalpaamruthaa modulated the activities of glycolytic enzymes (hexokinase, phosphogluco-isomerase, aldolase and glucose-6-phosphate dehydrogenase), gluconeogenic enzymes (glucose-6-phosphatase and fructose-1, 6-bisphosphatase) and glycogenolytic enzyme (glycogen phosphorylase) along with increased glycogen content in the liver of CVD-induced rats. The activities of isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, α-ketoglutarate dehydrogenase, Complexes and ATPases (Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase) were decreased in CVD-induced rats, which were ameliorated by the treatment with Kalpaamruthaa. This study ascertained the efficacy of Kalpaamruthaa for the treatment of CVD in diabetes through the modulation of metabolizing enzymes and mitochondrial dysfunction.

  17. Effect of hindlimb suspension on cardiovascular responses to sympathomimetics and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Overton, J. Michael; Tipton, Charles M.

    1990-01-01

    To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: (1) cage control (n = 15, CON), (2) horizontal suspension (n = 15, HOZ), and (3) head-down suspension (n = 18, HDS). Testing included lower body negative pressure administered during chloralose-urethan anesthesia and graded doses of sympathomimetic agents (norepinephrine, phenylephrine, and tyramine) administered to conscious unrestrained animals. Both HDS and HOZ were associated with a small decrease in the hypotensive response to lower body negative pressure. The HOZ group, but not the HDS group, exhibited augmented reflex tachycardia. Furthermore, both HDS and HOZ groups manifested reduced pressor responses to phenylephrine after treatment. These reductions were associated with significantly attenuated increases in mesenteric vascular resistance. However, baroreflex control of heart rate was not altered by the treatment conditions. Collectively, these results indicate that 9 days of HDS in rats does not elicit hemodynamic response patterns generally associated with cardiovascular deconditioning induced by hypogravic conditions.

  18. Effect of hindlimb suspension on cardiovascular responses to sympathomimetics and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Overton, J. Michael; Tipton, Charles M.

    1990-01-01

    To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: (1) cage control (n = 15, CON), (2) horizontal suspension (n = 15, HOZ), and (3) head-down suspension (n = 18, HDS). Testing included lower body negative pressure administered during chloralose-urethan anesthesia and graded doses of sympathomimetic agents (norepinephrine, phenylephrine, and tyramine) administered to conscious unrestrained animals. Both HDS and HOZ were associated with a small decrease in the hypotensive response to lower body negative pressure. The HOZ group, but not the HDS group, exhibited augmented reflex tachycardia. Furthermore, both HDS and HOZ groups manifested reduced pressor responses to phenylephrine after treatment. These reductions were associated with significantly attenuated increases in mesenteric vascular resistance. However, baroreflex control of heart rate was not altered by the treatment conditions. Collectively, these results indicate that 9 days of HDS in rats does not elicit hemodynamic response patterns generally associated with cardiovascular deconditioning induced by hypogravic conditions.

  19. Alterations in viscoelastic properties following premature birth may lead to hypertension and cardiovascular disease development in later life.

    PubMed

    Tauzin, L

    2015-01-01

    The aim of this review was to identify the underlying relationship between preterm birth and the development of cardiovascular diseases. Preterm birth significantly affects the elastin content and viscoelastic properties of the vascular extracellular matrix in human arteries. Inadequate elastin synthesis during early development may cause a permanent increase in arterial stiffness in adulthood. Early and permanent alterations in viscoelastic properties may lead to hypertension and cardiovascular disease development in adults born prematurely. ©2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  20. Cardiovascular and phrenic nerve responses to stimulation of the amygdala central nucleus in the anaesthetized rabbit.

    PubMed Central

    Cox, G E; Jordan, D; Paton, J F; Spyer, K M; Wood, L M

    1987-01-01

    1. The cardiovascular responses to electrical stimulation of the central nucleus of the amygdala (c.n.) have been studied in chloralose-anaesthetized rabbits. A pattern of response involving bradycardia, hypotension and hind-limb vasodilatation, accompanied by an increase in the rate of phrenic nerve discharge, was evoked only in response to stimulation within the medial portion of the c.n. 2. The cardiovascular responses were not secondary to the changes in respiratory activity since they were unaffected by altering central respiratory drive by either hypo- or hyperventilation of the animal. 3. The bradycardia was attenuated by the administration of atropine sulphate and abolished by the subsequent administration of propranolol, which when given alone attenuated the bradycardia. Atropine or propranolol given alone also attenuated the hypotension evoked by medial c.n. stimulation but the concurrent hind-limb vasodilatation was unaffected. 4. Atenolol, which unlike propranolol does not cross the blood-brain barrier, had little effect on the bradycardia in response to medial c.n. stimulation, but the subsequent administration of atropine abolished it. The hypotension in response to medial c.n. stimulation was also unaffected by atenolol. 5. The vasodilatation in response to medial c.n. stimulation was abolished by administration of guanethidine even after restoration of hind-limb perfusion pressure to control values by the infusion of angiotensin II into the hind-limb perfusion circuit. 6. Electrical stimulation of areas within 0.5 mm of the medial c.n. also resulted in bradycardia but then it was accompanied by hypertension and hind-limb vasoconstriction. Stimulation of areas 1.0 mm distant to the medial c.n. resulted in small and inconsistent cardiovascular responses. 7. These results show that hind-limb vasodilatation, mediated by withdrawal of sympathetic tone, occurs in response to stimulation within the medial c.n. of the rabbit and is in part responsible for

  1. The cardiovascular response to passive movement is joint dependent.

    PubMed

    Burns, Keith J; Pollock, Brandon S; McDaniel, John

    2016-03-01

    The cardiovascular responses to passive limb movement (PLM) at the knee are well established, however, responses to PLM at other joints involving smaller muscle volume are unknown. To compare the cardiovascular responses to passive movement at other joints, 10 participants underwent a PLM protocol in which the wrist, elbow, ankle, and knee joints were passively extended and flexed at 1 Hz for 1 min. Heart rate (HR), mean arterial blood pressure (MAP), and arterial blood flow to that limb segment (BF) were measured and vascular conductance (VC) was calculated for a 30-sec baseline period and for 3-sec intervals throughout PLM protocols. PLM of the knee and elbow resulted in significant increases in BF and VC from baseline values with peak values 180% (P < 0.001) greater than baseline. PLM of the elbow resulted in significant increases in BF and VC from baseline values with peak values 109% and 115% (P < 0.001) greater than baseline, respectively. No changes in BF and VC were observed in the ankle and wrist. Furthermore, the greater increase in blood flow per limb segment volume in the thigh and upper arm (62.8 ± 36.5 and 55.5 ± 30.3 mL min(-1) L(-1), respectively) compared to the forearm and lower leg (23.6 ± 16.7 and 19.1 ± 10.3 mL min(-1) L(-1), respectively) indicates the limb volume is not solely responsible for the differences in the hyperemic responses. These data indicate that the use of PLM to assess vascular function or as a rehabilitation modality to maintain vascular health may be most appropriate for the muscles that span the elbow and knee. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  2. Response patterns and cardiovascular effects during response sequence acquisition by humans.

    PubMed Central

    Kelly, T H; Fischman, M W; Foltin, R W; Brady, J V

    1991-01-01

    The effects of temporal delays imposed between successive responses and of vitamin C administration were examined on the acquisition of response sequences and on cardiovascular reactivity during sequence acquisition. Thirteen adult subjects (6 female, 7 male), in good health, gave written consent prior to participating in 12 weekly 45-min sessions. Points, exchanged for money after each session, were presented when subjects completed 15-response sequences on a touch-sensitive three-response keypad. A position counter increased from 0 to 14 as subjects emitted correct responses in the sequence. Four novel 15-response sequences were presented each session. No delays were imposed between successive responses during the acquisition of one sequence; delays were imposed immediately following each response during the acquisition of a second sequence, thereby delaying response feedback; delays were imposed following feedback during acquisition of a third sequence, resulting in the removal of the stimulus correlated with sequence position; and, as a control condition, delays were imposed following feedback, but stimuli correlated with sequence position were reinstated prior to the next response during acquisition of a fourth sequence. Subjects were exposed to one of two delay durations (0.2 and 0.5 or 0.5 and 1.0 s) each session, and delay durations alternated every session. During Weeks 5 to 8, subjects received 3 grams of vitamin C per day, whereas during Weeks 1 to 4 and 9 to 12, subjects received placebo under single-blind conditions. All subjects acquired the sequences, as evidenced by decreasing percentages of incorrect responses across trials. When temporal delays were imposed between successive responses during sequence acquisition, acquisition efficiency was enhanced. Examination of response latencies suggested that the status of preceding responses (i.e., correct or incorrect) rather than the status of the position counter influenced subsequent responding

  3. Acute Cardiovascular Response to Sign Chi Do Exercise

    PubMed Central

    Rogers, Carol E.; Carlson, John; Garver, Kayla

    2015-01-01

    Safe and gentle exercise may be important for older adults overcoming a sedentary lifestyle. Sign Chi Do (SCD), a novel form of low impact exercise, has shown improved balance and endurance in healthy older adults, and there have been no SCD-related injuries reported. Sedentary older adults are known to have a greater cardiovascular (CV) response to physical activity than those who regularly exercise. However their CV response to SCD is unknown. This study explored the acute CV response of older adults to SCD. Cross-sectional study of 34 sedentary and moderately active adults over age 55 with no previous experience practicing SCD. Participants completed a 10 min session of SCD. CV outcomes of heart rate, blood pressure, rate pressure product were recorded at 0, 5, 10 min of SCD performance, and after 10 min of rest. HR was recorded every minute. There was no difference in CV scores of sedentary and moderately active older adults after a session of SCD-related activity. All CV scores increased at 5 min, were maintained at 10 min, and returned to baseline within 10 min post SCD (p < 0.05). SCD may be a safe way to increase participation in regular exercise by sedentary older adults. PMID:27417797

  4. Transient middle cerebral artery occlusion and reperfusion alters inducible NOS expression within the ventrolateral medulla and modulates cardiovascular function during static exercise.

    PubMed

    Ally, Ahmmed; Maher, Timothy J

    2011-09-01

    A major cause of stroke is cerebral ischemia in regions supplied by the middle cerebral artery (MCA). In this study, we hypothesized that compromised cardiovascular function during static exercise may involve altered expression of inducible NOS (iNOS) protein within the rostral ventrolateral medulla (RVLM) and caudal ventrolateral medulla (CVLM). We compared cardiovascular responses and iNOS protein expression within the left and right sides of both RVLM and CVLM in sham-operated rats and in rats with a 90 min left-sided MCA occlusion (MCAO) followed by 24 h of reperfusion. Increases in blood pressure during a static muscle contraction were attenuated in MCAO rats compared with sham-operated rats. Also, iNOS expression within the left RVLM was augmented compared with the right RVLM in MCAO rats and compared with both RVLM quadrants in sham-operated rats. In contrast, compared with sham-operated rats and the right CVLM of MCAO rats, iNOS expression was attenuated in the left CVLM in left-sided MCAO rats. These data suggest that the attenuation of pressor responses during static exercise in MCAO rats involves overexpression of iNOS within the ipsilateral RVLM and attenuation in iNOS within the ipsilateral CVLM. Differential expression of iNOS within the medulla plays a role in mediating cardiovascular responses during static exercise following stroke.

  5. Impact of vitamin D3 on cardiovascular responses to glucocorticoid excess.

    PubMed

    Ahmed, Mona A

    2013-06-01

    Although the cardiovascular system is not a classical target for 1,25-dihydroxyvitamin D3, both cardiac myocytes and vascular smooth muscle cells respond to this hormone. The present study aimed to elucidate the effect of active vitamin D3 on cardiovascular functions in rats exposed to glucocorticoid excess. Adult male Wistar rats were allocated into three groups: control group, dexamethasone (Dex)-treated group receiving Dex (200 μg/kg) subcutaneously for 12 days, and vitamin D3-Dex-treated group receiving 1,25-(OH)2D3 (100 ng/kg) and Dex (200 μg/kg) subcutaneously for 12 days. Rats were subjected to measurement of systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressures and heart rate. Rate pressure product (RPP) was calculated. Rats' isolated hearts were perfused in Langendorff preparation and studied for basal activities (heart rate, peaked developed tension, time to peak tension, half relaxation time, and myocardial flow rate) and their responses to isoproterenol infusion. Blood samples were collected for determination of plasma level of nitrite, nitric oxide surrogate. Dex-treated group showed significant increase in SBP, DBP, MAP, and RPP, as well as cardiac hypertrophy and enhancement of basal cardiac performance evidenced by increased heart rate, rapid and increased contractility, and accelerated lusitropy, together with impaired contractile and myocardial flow rate responsiveness to beta-adrenergic activation and depressed inotropic and coronary vascular reserves. Such alterations were accompanied by low plasma nitrite. These changes were markedly improved by vitamin D3 treatment. In conclusion, vitamin D3 is an efficacious modulator of the deleterious cardiovascular responses induced by glucocorticoid excess, probably via accentuation of nitric oxide.

  6. Cardiovascular disease-induced thermal responses during passive heat stress: an integrated computational study.

    PubMed

    Zhang, Xiancheng; Noda, Shigeho; Himeno, Ryutaro; Liu, Hao

    2016-11-01

    The cardiovascular system plays a crucial role in human thermoregulation; cardiovascular diseases may lead to significantly degrading the thermoregulation ability for patients during exposure to heat stress. To evaluate the thermal responses of patients with common chronic cardiovascular diseases, we here propose an integrated computational model by coupling a two-node thermoregulation model with a closed-loop, multi-compartment, lumped-parameter cardiovascular model. This bioheat transfer model is validated, capable to predict cardiovascular functions and thermal responses under varying environmental conditions. Our results demonstrate that the cardiovascular disease-induced reduction in cardiac output and skin blood flow causes extra elevation in core temperature during hyperthermic challenges. In addition, a combination of aging, obesity, and cardiovascular diseases shows a pronounced increase in core temperature during heat exposure, which implies that such combined effect may increase the risk of heat-related morbidity and mortality. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. The dorsomedial hypothalamus and the central pathways involved in the cardiovascular response to emotional stress.

    PubMed

    Fontes, M A P; Xavier, C H; de Menezes, R C A; Dimicco, J A

    2011-06-16

    Psychological stress elicits increases in sympathetic activity accompanied by a marked cardiovascular response. Revealing the relevant central mechanisms involved in this phenomenon could contribute significantly to our understanding of the pathogenesis of stress-related cardiovascular diseases, and the key to this understanding is the identification of the nuclei, pathways and neurotransmitters involved in the organization of the cardiovascular response to stress. The present review will focus specifically on the dorsomedial hypothalamus, a brain region now known to play a primary role in the synaptic integration underlying the cardiovascular response to emotional stress. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Chronic ocular hypertension alters local retinal responsiveness.

    PubMed Central

    Ofri, R; Dawson, W W; Foli, K; Gelatt, K N

    1993-01-01

    Electrophysiological responses of the retina and visual cortex to a series of grating stimuli (6-768 minutes of arc) were recorded in seven sessions using normal beagles, 21 sessions using beagles afflicted with inherited ocular hypertension, and 12 sessions using rhesus monkeys. A 15 degrees field centred around the animal's area centralis or fovea was used to stimulate the central retina. A 30 degrees field, centred on the same spot, was then used to stimulate the larger area. Two recording series were completed on each animal, with both field sizes presented in each recording session. The first recording took place 30 minutes after and the second 2 hours after the injection of thiamylal sodium. Only the signals from the toroidal 15 degrees of the retina of the hypertensive dogs were remarkably larger during the second recording (p = 0.001). No significant differences were found between the two recordings from the retinas of normal dogs or monkeys, nor were there any significant differences between the two recordings from above the cortex in any group. Several hypotheses are proposed to explain the basis for the interaction of thiamylal with the more peripheral retinal function in clinically glaucomatous dogs. PMID:8025048

  9. Mechanical response of cardiovascular stents under vascular dynamic bending.

    PubMed

    Xu, Jiang; Yang, Jie; Huang, Nan; Uhl, Christopher; Zhou, Yihua; Liu, Yaling

    2016-02-20

    Currently, the effect of vascular dynamic bending (VDB) has not been fully considered when studying cardiovascular stents' long-term mechanical properties, as the previous studies about stent's mechanical properties mostly focus on the effect of vascular pulsation (VP). More and more clinical reports suggested that the effect of VDB have a significant impact on stent. In this paper, an explicit-implicit coupling simulation method was applied to analyze the mechanical responses of cardiovascular stents considering the effect of VDB. The effect of VP on stent mechanical properties was also studied and compared to the effect of VDB. The results showed that the dynamic bending deformation occurred in stents due to the effect of VDB. The effects of VDB and VP resulted in alternating stress states of the stent, while the VDB alternate stresses effective on the stent were almost three times larger than that of the VP. The stress concentration under VDB mainly occurred in bridge struts and the maximal stress was located in the middle loops of the stent. However, the stress distributed uniformly in the stents under the effect of VP. Stent fracture occurred more frequently as a result of VDB with the predicted fracture position located in the bridging struts of the stent. These results are consistent with the reported data in clinical literatures. The stress of the vessel under VDB was higher, than that caused by VP. The results showed that the effect of VDB has a significant impact on the stent's stress distribution, fatigue performance and overall stress on the vessel, thus it is necessary to be considered when analyzing stent's long-term mechanical properties. Meanwhile, the results showed that the explicit-implicit coupling simulation can be applied to analyze stent mechanical properties.

  10. Cardiovascular and inflammatory response to cholecystokinin during endotoxemic shock.

    PubMed

    Saia, Rafael Simone; Bertozi, Giuliana; Mestriner, Fabíola Leslie; Antunes-Rodrigues, José; Queiróz Cunha, Fernando; Cárnio, Evelin Capellari

    2013-01-01

    Cholecystokinin (CCK) was first described as a gastrointestinal hormone, but its receptors have been located in cardiac and vascular tissues, as well as in immune cells. Our aims were to investigate the role of CCK on lipopolysaccharide (LPS)-induced hypotension and its ability to modulate previously reported inflammatory mediators, therefore affecting cardiovascular function. To conduct these experiments, rats had their jugular vein cannulated for drug administration, and also, the femoral artery cannulated for mean arterial pressure (MAP) and heart rate records. Endotoxemia induced by LPS from Escherichia coli (1.5 mg/kg; i.v.) stimulated the release of CCK, a progressive drop in MAP, and increase in heart rate. Plasma tumor necrosis factor α (TNF-α), interleukin 10 (IL-10), nitrate, vasopressin, and lactate levels were elevated in the endotoxemic rats. The pretreatment with proglumide (nonselective CCK antagonist; 30 mg/kg; i.p.) aggravated the hypotension and also increased plasma TNF-α and lactate levels. On the other hand, CCK (0.4 μg/kg; i.v.) administered before LPS significantly restored MAP, reduced aortic and hepatic inducible nitric oxide synthase (iNOS) production, and elevated plasma vasopressin and IL-10 concentrations; it did not affect TNF-α. Physiological CCK concentration reduced nitrite and iNOS synthesis by peritoneal macrophages, possibly through a self-regulatory IL-10-dependent mechanism. Together, these data suggest a new role for the peptide CCK in modulating MAP, possibly controlling the inflammatory response, stimulating the anti-inflammatory cytokine, IL-10, and reducing vascular and macrophage iNOS-derived nitric oxide production. Based on these findings, CCK could be used as an adjuvant therapeutic agent to improve cardiovascular function.

  11. Computational modeling of cardiovascular response to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Heldt, Thomas; Shim, Eun B.; Kamm, Roger D.; Mark, Roger G.

    2002-01-01

    The objective of this study is to develop a model of the cardiovascular system capable of simulating the short-term (< or = 5 min) transient and steady-state hemodynamic responses to head-up tilt and lower body negative pressure. The model consists of a closed-loop lumped-parameter representation of the circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes. Model parameters are largely based on literature values. Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. On the basis of experimental evidence, we adjusted some model parameters to simulate experimental data. Orthostatic stress simulations are not statistically different from experimental data (two-sided test of significance with Bonferroni adjustment for multiple comparisons). Transient response characteristics of heart rate to tilt also compare well with reported data. A case study is presented on how the model is intended to be used in the future to investigate the effects of post-spaceflight orthostatic intolerance.

  12. Computational modeling of cardiovascular response to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Heldt, Thomas; Shim, Eun B.; Kamm, Roger D.; Mark, Roger G.

    2002-01-01

    The objective of this study is to develop a model of the cardiovascular system capable of simulating the short-term (< or = 5 min) transient and steady-state hemodynamic responses to head-up tilt and lower body negative pressure. The model consists of a closed-loop lumped-parameter representation of the circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes. Model parameters are largely based on literature values. Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. On the basis of experimental evidence, we adjusted some model parameters to simulate experimental data. Orthostatic stress simulations are not statistically different from experimental data (two-sided test of significance with Bonferroni adjustment for multiple comparisons). Transient response characteristics of heart rate to tilt also compare well with reported data. A case study is presented on how the model is intended to be used in the future to investigate the effects of post-spaceflight orthostatic intolerance.

  13. Cerebrovascular, cardiovascular and strength responses to acute ammonia inhalation.

    PubMed

    Perry, Blake G; Pritchard, Hayden J; Barnes, Matthew J

    2016-03-01

    Ammonia is used as a stimulant in strength based sports to increase arousal and offset fatigue however little is known about its physiological and performance effects. The purpose of this study was twofold (1) establish the physiological response to acute ammonia inhalation (2) determine whether the timing of the physiological response corresponds with a performance enhancement, if any. Fifteen healthy males completed two trials. Trial one investigated the beat-to-beat middle cerebral artery blood flow velocity (MCAv), heart rate (HR) and mean arterial pressure (MAP) response to ammonia inhalation. During trial two, participants performed a maximal single mid-thigh pull (MTP) at various time points following ammonia inhalation in a randomised order: MTPs were conducted immediately, 15, 30 and 60 s following ammonia inhalation. A MTP with no ammonia inhalation served as the control. During this trial maximal MTP force, rate of force development (RFD) and electromyography (EMG) activity were recorded. MCAvmean increased and peaked on average by 6 cm s(-1) (P < 0.001), 9.4 ± 5.5 s following ammonia inhalation. Similarly, HR was increased by 6 ± 11 beats per minute 15 s following ammonia inhalation (P < 0.001). MAP remained unchanged following inhalation (P = 0.51). The use and timing of ammonia inhalation had no effect on maximal force, RFD or EMG (all P > 0.2) compared to control. MCAv was elevated despite no increase in MAP occurring; this is indicative of a cerebrovascular vasodilation. Despite the marked cerebrovascular and cardiovascular response to ammonia inhalation no ergogenic effect was observed during the MTP, irrespective of the timing of administration.

  14. Ultrastructural alterations in allylamine cardiovascular toxicity. Late myocardial and vascular lesions.

    PubMed Central

    Boor, P. J.; Ferrans, V. J.

    1985-01-01

    The late myocardial and vascular ultrastructural changes in rat hearts following consumption of the cardiovascular toxin allylamine were studied. Rats were given 0.1% allylamine HCl in drinking water for 10-104 days. From 10 to 21 days, there was organization of acute myocardial necrosis by macrophages and scattered polymorphonuclear leukocytes with prominent interstitial-cell proliferation. Alterations at 21-104 days included extensive scarring with formation of dense mature collagen with scattered fibroblasts present, grossly evident left-ventricular aneurysm, and gross and microscopic changes similar to those observed in the secondary form of endocardial fibroelastosis. Areas of scar contained highly cellular foci of smooth-muscle cells, myofibroblasts, and abundant extracellular elastin. Cardiac myocytes frequently showed markedly disorganized myofilaments, bizarrely distorted mitochondria with condensed cristae, and other severe degenerative changes. Small vessels within and adjacent to scar showed proliferation of intimal smooth-muscle cells. Endothelial lesions or recent or organized thrombi were not seen. Focal endocardial metaplasia, consisting of both chondroid and osseous tissue, was found in areas of transmural scarring, or ventricular aneurysm. Chondrocytes had the overall nuclear and cellular morphology, abundant rough endoplasmic reticulum, and surrounding lacunae typical of mature fibrocartilage. In some areas, the collagen matrix was undergoing calcification with the typical cross-banded pattern of calcifying connective tissue. Osteocytes were located in a densely calcified bone matrix and displayed characteristic cellular extensions into surrounding canaliculi. These findings indicate a severe myocardial, small-vessel, and endocardial injury during the course of chronic allylamine intoxication. Images Figure 13 Figure 14 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 15 Figure

  15. Metabolic and Cardiovascular Response to Shallow Water Exercise in Young and Older Women.

    ERIC Educational Resources Information Center

    Campbell, Jennifer A.; D'Acquisto, Leo J.; D'Acquisto, Debra M.; Cline, Michael G.

    2003-01-01

    Compared the metabolic and cardiovascular responses of young and older women while performing shallow water exercise (SWE). Overall, SWE elicited metabolic and cardiovascular responses that met American College of Sports Medicine's guidelines for establishing health benefits. Older females self-selected a greater relative exercise intensity during…

  16. Metabolic and Cardiovascular Response to Shallow Water Exercise in Young and Older Women.

    ERIC Educational Resources Information Center

    Campbell, Jennifer A.; D'Acquisto, Leo J.; D'Acquisto, Debra M.; Cline, Michael G.

    2003-01-01

    Compared the metabolic and cardiovascular responses of young and older women while performing shallow water exercise (SWE). Overall, SWE elicited metabolic and cardiovascular responses that met American College of Sports Medicine's guidelines for establishing health benefits. Older females self-selected a greater relative exercise intensity during…

  17. The Effects of Behavior Therapy, Self-Relaxation, and Transcendental Meditation on Cardiovascular Stress Response.

    ERIC Educational Resources Information Center

    Puente, Antonio E.; Beiman, Irving

    1980-01-01

    Compared Behavior Therapy (BT), self-relaxation (SR), transcendental meditation (TM), and a waiting-list control group (WL) on measures of cardiovascular and subjective stress response. Results indicate that BT and SR were more effective than either TM or WL in reducing cardiovascular stress response. (Author)

  18. Cardiovascular Response to Recreational Hockey in Middle-Aged Men.

    PubMed

    Goodman, Zack A; Thomas, Scott G; Wald, Robert C; Goodman, Jack M

    2017-06-15

    The present study examined the hemodynamic response to recreational pick-up hockey relative to maximal exercise testing in middle-aged men. A total of 23 men with a mean age of 53 ± 7 years were studied. Graded exercise testing on a cycle ergometer determined maximal oxygen consumption, blood pressure (BP), and heart rate (HR). Ambulatory BP and Holter electrocardiographic monitoring was performed during one of their weekly hockey games (mean duration = 45 ± 7.2 minutes): for "On-Ice" responses (PLAY; data recorded while standing immediately after a shift; 8.0 ± 1.4 shifts per game) and during seated recovery (BENCH), 15 minutes after the game. On-Ice HRs and BPs were significantly higher than values obtained during maximal cycle exercise, respectively (HR 174 ± 8.9 vs 163 ± 11.0 beats/min) (systolic blood pressure 202 ± 20 vs 173 ± 31 mm Hg; p <0.05). Both systolic and diastolic blood pressures decreased significantly throughout the duration of the game, whereas HR increased from 139 ± 20 to 155 ± 16 beats/min during the game. The myocardial oxygen demand (myocardial time tension index) increased significantly during PLAY concurrent with a decrease in estimated myocardial oxygen supply (diastolic pressure time index), with the endocardial viability ratio during PLAY demonstrating a significant decrease during the third quarter of the game (1.25 ± 0.24) versus the first quarter (1.56 ± 0.30), which remained depressed 15 minutes post-game (p <0.05). In conclusion, recreational pick-up hockey in middle-aged men is an extremely vigorous interval exercise with increasing relative intensity as the game progresses. Hockey elicits peak BPs and HRs that can exceed values observed during maximal exercise testing and is characterized by progressive increases in myocardial oxygen demand and lowered supply during PLAY and BENCH time. Given the progressive and high cardiovascular demands, caution is warranted when estimating the cardiovascular demands of hockey

  19. [Abnormal autonomic cardiovascular responses in patients with sickle cell anemia].

    PubMed

    Romero-Vecchione, E; Pérez, O; Wessolosky, M; Rosa, F; Liberatore, S; Vásquez, J

    1995-10-01

    To evaluate the presence of anomalies of the autonomic reflex cardiovascular response in patients with chronic sickle-cell anaemia. The study was extended to 30 patients with sickle-cell anaemia, 10 patients with iron-lack anaemia and 30 healthy subjects. Age and sex distribution was similar in each group. To be included in the study, patients should have had no painful crisis or blood transfusion in the 6 months previous to the assay. Clinico-laboratory survey, chest x-ray and EKG were performed in every case. Blood cell count and abnormal haemoglobin study on cellulose acetate were carried out as well. The evaluation of reflex autonomic responses was performed by means of active orthostatism, cold pressor test, Valsalva maneuver and urine catecholamine output. The statistical analysis was performed with the variance analysis (ANOVA) for multiple groups. The following abnormalities were found: 12 patients had haemoglobin SS, 8 had haemoglobin SS and F, 3 had haemoglobin SC, 2 had haemoglobin S and beta-thalassaemia, and 5 had combined haemoglobin SS,F and A2. Systolic pressure and heart frequency in the supine position were similar in all groups. Diastolic pressure was lower in the sickle-cell anaemia group with respect to the normals. Patients with sickle-cell disease had lower heart frequency in the active orthostatism test with regard to the other groups, along with paradoxal changes in systolic pressure and lesser increase of the diastolic pressure. Significantly lower response to the cold pressor test was seen in the sickle-cell patients as compared with the iron-lack cases and the normal controls. Reduced sympathetic tachycardia was seen with the Valsalva maneuver, whereas the bradycardia was similar to the other groups. The urine noradrenaline in output was significantly lower in the sickle-cell patients, it was normal in the other groups (p < 0.01). These results suggest a defective sympathetic activity of heart and arteries in patients with sickle

  20. Blood pressure responses to dietary sodium: Association with autonomic cardiovascular function in normotensive adults.

    PubMed

    Matthews, Evan L; Brian, Michael S; Edwards, David G; Stocker, Sean D; Wenner, Megan M; Farquhar, William B

    2017-08-06

    Blood pressure responses to dietary sodium vary widely person-to-person. Salt sensitive rodent models display altered autonomic function, a trait thought to contribute to poor cardiovascular health. Thus, we hypothesized that increased salt sensitivity (SS) in normotensive humans would be associated with increased muscle sympathetic nerve activity (MSNA), decreased high frequency heart rate variability (HF-HRV), and decreased baroreflex sensitivity. Healthy normotensive men and women completed 1week of high (300mmol·day(-1)) and 1week of low (20mmol·day(-1)) dietary sodium (random order) with 24h mean arterial pressure (MAP) assessed on the last day of each diet to assess SS. Participants returned to the lab under habitual sodium conditions for testing. Forty-two participants are presented in this analysis, 19 of which successful MSNA recordings were obtained (n=42: age 39±2yrs., BMI 24.3±0.5kg·(m(2))(-1), MAP 83±1mmHg, habitual urine sodium 93±7mmol·24h(-1); n=19: MSNA burst frequency 20±2 bursts·min(-1)). The variables of interest were linearly regressed over the magnitude of SS. Higher SS was associated with increased MSNA (burst frequency: r=0.469, p=0.041), decreased HF-HRV (r=-0.349, p=0.046), and increased LF/HF-HRV (r=0.363, p=0.034). SS was not associated with sympathetic or cardiac baroreflex sensitivity (p>0.05). Multiple regression analysis accounting for age found that age, not SS, independently predicted HF-HRV (age adjusted no longer significant; p=0.369) and LF/HF-HRV (age adjusted p=0.273). These data suggest that age-related salt sensitivity of blood pressure in response to dietary sodium is associated with altered resting autonomic cardiovascular function. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Cardiovascular response to bouts of exercise with blood flow restriction

    PubMed Central

    Bunevicius, Kestutis; Sujeta, Arturas; Poderiene, Kristina; Zachariene, Birute; Silinskas, Viktoras; Minkevicius, Rimantas; Poderys, Jonas

    2016-01-01

    [Purpose] Occlusion training with low-intensity resistance exercises and blood flow restriction increases muscle cross-sectional area and strength. This form of training is used in rehabilitation; therefore, the aim of this study was to examine the effect of one occlusion training session on the cardiovascular response to bouts of exercise. [Subjects and Methods] Two groups took part: a control group without blood flow restriction and an experimental group with blood flow restriction. A single training session was used with the exercise intensity set at 40% of the one repetition maximum. Maximum voluntary contraction, arterial blood pressure, and electrocardiogram measurements were performed. [Results] Heart rate was slightly higher in the control group. The performed training had no effect on diastolic blood pressure in either group, however, a tendency for a small systolic blood pressure increase was observed during the session in the experimental group. JT interval changes did not reveal significant differences between groups. There were no significant changes in ST-segment depression during the exercise or at rest. A lower tendency for JT/RR increases was observed during the repeated exercise tasks with partial blood flow restriction. [Conclusion] Low intensity exercises carried out with a partial blood flow restriction do not result in significant overload of cardiac function. PMID:28174436

  2. Cardiovascular response to bouts of exercise with blood flow restriction.

    PubMed

    Bunevicius, Kestutis; Sujeta, Arturas; Poderiene, Kristina; Zachariene, Birute; Silinskas, Viktoras; Minkevicius, Rimantas; Poderys, Jonas

    2016-12-01

    [Purpose] Occlusion training with low-intensity resistance exercises and blood flow restriction increases muscle cross-sectional area and strength. This form of training is used in rehabilitation; therefore, the aim of this study was to examine the effect of one occlusion training session on the cardiovascular response to bouts of exercise. [Subjects and Methods] Two groups took part: a control group without blood flow restriction and an experimental group with blood flow restriction. A single training session was used with the exercise intensity set at 40% of the one repetition maximum. Maximum voluntary contraction, arterial blood pressure, and electrocardiogram measurements were performed. [Results] Heart rate was slightly higher in the control group. The performed training had no effect on diastolic blood pressure in either group, however, a tendency for a small systolic blood pressure increase was observed during the session in the experimental group. JT interval changes did not reveal significant differences between groups. There were no significant changes in ST-segment depression during the exercise or at rest. A lower tendency for JT/RR increases was observed during the repeated exercise tasks with partial blood flow restriction. [Conclusion] Low intensity exercises carried out with a partial blood flow restriction do not result in significant overload of cardiac function.

  3. Potentiation of cardiovascular responses to hydralazine by diverse hydrazine derivatives.

    PubMed

    Vidrio, H

    1994-10-01

    After the observation that in anesthetized rats the antitubercular agent isoniazid potentiates the hypotensive effect of the vasodilator hydralazine (H) and transforms the accompanying reflex tachycardia to bradycardia, a number of hydrazine (HYD) derivatives were tested for this interaction in pentobarbital-anesthetized rats. All HYDs studied elicited this response in varying degrees, isoniazid, thiosemicarbazide and thiocarbohydrazide being the most active. Experiments were then carried out to explore the possibility of an influence of the HYDs on reflex reactions to H due to interaction with pyridoxal, inhibition of glutamic acid decarboxylase and decreased levels of brain gamma-aminobutyric acid. Although the H-HYDs interaction was prevented by vagotomy, it was unaffected by exogenous pyridoxal, did not occur with the alpha adrenergic antagonist prazosin and was not mimicked by non-HYD pyridoxal reactors. In other experiments, pharmacokinetic interactions and monoamine oxidase inhibition were ruled out as alternative explanations for this phenomenon. It was concluded that the H-HYDs interaction is not related to a possible influence of these drugs on central gamma-aminobutyric acid cardiovascular regulation and that other presently unknown mechanisms are involved.

  4. Dietary methionine restriction in mice elicits an adaptive cardiovascular response to hyperhomocysteinemia.

    PubMed

    Ables, Gene P; Ouattara, Amadou; Hampton, Thomas G; Cooke, Diana; Perodin, Frantz; Augie, Ines; Orentreich, David S

    2015-03-06

    Dietary methionine restriction (MR) in rodents increased lifespan despite higher heart-to-body weight ratio (w/w) and hyperhomocysteinemia, which are symptoms associated with increased risk for cardiovascular disease. We investigated this paradoxical effect of MR on cardiac function using young, old, and apolipoprotein E-deficient (ApoE-KO) mice. Indeed, MR animals exhibited higher heart-to-body weight ratio (w/w) and hyperhomocysteinemia with a molecular pattern consistent with cardiac stress while maintaining the integrity of cardiac structure. Baseline cardiac function, which was measured by non-invasive electrocardiography (ECG), showed that young MR mice had prolonged QRS intervals compared with control-fed (CF) mice, whereas old and ApoE-KO mice showed similar results for both groups. Following β-adrenergic challenge, responses of MR mice were either similar or attenuated compared with CF mice. Cardiac contractility, which was measured by isolated heart retrograde perfusion, was similar in both groups of old mice. Finally, the MR diet induced secretion of cardioprotective hormones, adiponectin and fibroblast growth factor 21 (FGF21), in MR mice with concomitant alterations in cardiac metabolic molecular signatures. Our findings demonstrate that MR diet does not alter cardiac function in mice despite the presence of hyperhomocysteinemia because of the adaptive responses of increased adiponectin and FGF21 levels.

  5. Anxious women do not show the expected decrease in cardiovascular stress responsiveness as pregnancy advances.

    PubMed

    Braeken, M A K A; Jones, A; Otte, R A; Widjaja, D; Van Huffel, S; Monsieur, G J Y J; van Oirschot, C M; Van den Bergh, B R H

    2015-10-01

    Altered stress responsiveness is a risk factor for mental and physical illness. In non-pregnant populations, it is well-known that anxiety can alter the physiological regulation of stress reactivity. Characterization of corresponding risks for pregnant women and their offspring requires greater understanding of how stress reactivity and recovery are influenced by pregnancy and women's anxiety feelings. In the current study, women were presented repeatedly with mental arithmetic stress tasks in the first and third pregnancy trimester and reported their trait anxiety using the state trait anxiety inventory. Cardiovascular stress reactivity in late pregnancy was lower than reactivity in the first pregnancy trimester (heart rate (HR): t(197)=4.98, p<.001; high frequency heart rate variability (HF HRV): t(196)=-2.09, p=.04). Less attenuation of stress reactivity occurred in more anxious women (HR: b=0.15, SE=0.06, p=.008; HF HRV: b=-10.97, SE=4.79, p=.02). The study design did not allow the influence of habituation to repeated stress task exposure to be assessed separately from the influence of pregnancy progression. Although this is a limitation, the clear differences between anxious and non-anxious pregnant women are important, regardless of the extent to which differing habituation between the groups is responsible. Less dampened stress reactivity through pregnancy may pose long-term risks for anxious women and their offspring. Follow-up studies are required to determine these risks.

  6. Poor Response to Periodontal Treatment May Predict Future Cardiovascular Disease.

    PubMed

    Holmlund, A; Lampa, E; Lind, L

    2017-07-01

    Periodontal disease has been associated with cardiovascular disease (CVD), but whether the response to the treatment of periodontal disease affects this association has not been investigated in any large prospective study. Periodontal data obtained at baseline and 1 y after treatment were available in 5,297 individuals with remaining teeth who were treated at a specialized clinic for periodontal disease. Poor response to treatment was defined as having >10% sites with probing pocket depth >4 mm deep and bleeding on probing at ≥20% of the sites 1 y after active treatment. Fatal/nonfatal incidence rate of CVD (composite end point of myocardial infarction, stroke, and heart failure) was obtained from the Swedish cause-of-death and hospital discharge registers. Poisson regression analysis was performed to analyze future risk of CVD. During a median follow-up of 16.8 y (89,719 person-years at risk), those individuals who did not respond well to treatment (13.8% of the sample) had an increased incidence of CVD ( n = 870) when compared with responders (23.6 vs. 15.3%, P < 0.001). When adjusting for calendar time, age, sex, educational level, smoking, and baseline values for bleeding on probing, probing pocket depth >4 mm, and number of teeth, the incidence rate ratio for CVD among poor responders was 1.28 (95% CI, 1.07 to 1.53; P = 0.007) as opposed to good responders. The incidence rate ratio among poor responders increased to 1.39 (95% CI, 1.13 to 1.73; P = 0.002) for those with the most remaining teeth. Individuals who did not respond well to periodontal treatment had an increased risk for future CVD, indicating that successful periodontal treatment might influence progression of subclinical CVD.

  7. Cardiovascular responses to arm static exercise in men with thoracic spinal cord lesions.

    PubMed

    Sakamoto, Keiko; Nakamura, Takeshi; Umemoto, Yasunori; Koike, Yumi; Sasaki, Yusuke; Tajima, Fumihiro

    2012-02-01

    Isometric muscle contraction (static exercise) induces circulatory response. Static exercise in individuals with thoracic spinal cord injury (TSCI) induces cardiovascular response and blood redistribution to the non-exercising muscles. The aim of our study was to determine the circulatory response during arm static exercise in individuals with TSCI and able-bodied (AB) controls. Mean blood pressure (MBP), heart rate (HR), cardiac output (CO), leg skin blood flow (SBF), and leg muscle blood flow (MBF) were recorded noninvasively, total peripheral resistance (TPR) was estimated by dividing MBP by CO, and hormonal changes were measured before, during and after static 35% maximal voluntary contraction (MVC) of the arm flexor muscles in seven male individuals with TSCI (T7-T11) and seven age-comparable AB control (32.2 ± 7.6 and 31.0 ± 4.7 years, respectively). The 35% MVC was similar in TSCI and AB individuals (107.3 ± 28.2 and 101.0 ± 22.5 N, respectively). HR, CO, MBP, TPR, SBF and MBF increased in both groups during arm static exercise. Plasma epinephrine concentration increased during arm static exercise in AB controls only (P < 0.05). Circulation to leg muscles was similar in TSCI and AB individuals and the lack of sympathetic vasoconstriction in the paralyzed leg area did not alter the cardiovascular responses during 35% MVC of arm static exercise. We conclude that sympathetic vasoconstriction in the resting leg area did not contribute to the pressor reflex during 35% MVC of arm static exercise.

  8. Acute Cardiovascular and Hemodynamic Responses to Low Intensity Eccentric Resistance Exercise with Blood Flow Restriction.

    PubMed

    Bazgir, Behzad; Rezazadeh Valojerdi, Mojtaba; Rajabi, Hamid; Fathi, Rouhollah; Ojaghi, Seyed Mojtaba; Emami Meybodi, Mohammad Kazem; Neto, Gabriel R; Rahimi, Mostafa; Asgari, Alireza

    2016-12-01

    Recently it has been suggested that low intensity (LI) resistance exercise (RE) alone or in combination with blood flow restriction (BFR) can be applied for cardiovascular function improvement or rehabilitation. The aim of the present study was to investigate the acute effects of LI eccentric RE with and without BFR on heart rate (HR), rate pressure product (RPP), blood pressure (BP) parameters [systolic, diastolic, and mean arterial pressure (MAP)], oxygen saturation (SpO2) and rate of perceived exertion (RPE). In a semi-experimental study 16 young adults (26.18 ± 3.67 years) volunteered and performed LI (30% maximum voluntary contraction) eccentric RE alone or combined with BFR. The results indicated that HR, RPP, and RPE increased significantly within both groups (P < 0.05); SBP and DBP increased significantly only with BFR (P < 0.05); MAP increased significantly during exercise without BFR (P < 0.05); and no change was observed in SpO2 in either groups (P > 0.05). Furthermore, studied parameters did not vary amongst different groups (P > 0.05). It is concluded that LI eccentric RE with BFR positively regulated the hemodynamic and cardiovascular responses. Therefore, the eccentric RE combined with BFR seems to be a good option for future studies with the aim of time efficacy, since it alters these parameters within normal values.

  9. Acute Cardiovascular and Hemodynamic Responses to Low Intensity Eccentric Resistance Exercise with Blood Flow Restriction

    PubMed Central

    Bazgir, Behzad; Rezazadeh Valojerdi, Mojtaba; Rajabi, Hamid; Fathi, Rouhollah; Ojaghi, Seyed Mojtaba; Emami Meybodi, Mohammad Kazem; Neto, Gabriel R.; Rahimi, Mostafa; Asgari, Alireza

    2016-01-01

    Background Recently it has been suggested that low intensity (LI) resistance exercise (RE) alone or in combination with blood flow restriction (BFR) can be applied for cardiovascular function improvement or rehabilitation. Objectives The aim of the present study was to investigate the acute effects of LI eccentric RE with and without BFR on heart rate (HR), rate pressure product (RPP), blood pressure (BP) parameters [systolic, diastolic, and mean arterial pressure (MAP)], oxygen saturation (SpO2) and rate of perceived exertion (RPE). Methods In a semi-experimental study 16 young adults (26.18 ± 3.67 years) volunteered and performed LI (30% maximum voluntary contraction) eccentric RE alone or combined with BFR. Results The results indicated that HR, RPP, and RPE increased significantly within both groups (P < 0.05); SBP and DBP increased significantly only with BFR (P < 0.05); MAP increased significantly during exercise without BFR (P < 0.05); and no change was observed in SpO2 in either groups (P > 0.05). Furthermore, studied parameters did not vary amongst different groups (P > 0.05). Conclusions It is concluded that LI eccentric RE with BFR positively regulated the hemodynamic and cardiovascular responses. Therefore, the eccentric RE combined with BFR seems to be a good option for future studies with the aim of time efficacy, since it alters these parameters within normal values. PMID:28144415

  10. Cardiovascular responses to microgravity - Adaptation, maladjustment, and countermeasures

    NASA Technical Reports Server (NTRS)

    Gaffney, F. Andrew

    1989-01-01

    Humans have worked in space for up to 237 days without significant inflight limitations, although major cardiovascular disability is seen following space flight of even a few days duration. Most of the cardiovascular research on microgravity deconditioning has been observational in character. Detailed studies of mechanisms and causes of postflight exercise intolerance, low blood pressure and fainting in astronauts and cosmonauts have not been done, despite almost 30 years of manned space flight. A review of possible mechanisms of postflight cardiovascular deconditioning and directions for study is provided.

  11. Cardiovascular responses to microgravity - Adaptation, maladjustment, and countermeasures

    NASA Technical Reports Server (NTRS)

    Gaffney, F. Andrew

    1989-01-01

    Humans have worked in space for up to 237 days without significant inflight limitations, although major cardiovascular disability is seen following space flight of even a few days duration. Most of the cardiovascular research on microgravity deconditioning has been observational in character. Detailed studies of mechanisms and causes of postflight exercise intolerance, low blood pressure and fainting in astronauts and cosmonauts have not been done, despite almost 30 years of manned space flight. A review of possible mechanisms of postflight cardiovascular deconditioning and directions for study is provided.

  12. Celecoxib does not alter cardiovascular and renal function during dietary salt loading.

    PubMed

    Wenner, Megan M; Edwards, David G; Ray, Chester A; Rose, William C; Gardner, Timothy J; Stillabower, Michael; Farquhar, William B

    2011-08-01

    1. Cyclo-oxygenase-2 (COX-2)-derived prostaglandins are important in controlling sodium excretion and renin release. In the present study, we tested the hypothesis that a clinical dose of celecoxib would impair urinary sodium excretion and elevate blood pressure (BP) during dietary salt loading. 2. Twelve normotensive individuals (mean (± SEM) age 35 ± 2 years) completed two separate 17 day dietary perturbations, one taking 200 mg/day celecoxib (CX2) and the other taking placebo (PL), randomized with a 1 month wash out. The controlled 17 day diet consisted of a 3 day run-in diet, 7 days of a low-salt (LS, 20 mmol sodium/day) diet and 7 days of a high-salt diet (HS, 350 mmol sodium/day) diet. The order in which the diets were applied was randomized. Data were collected on the last day of the LS and HS diets. 3. Plasma and urinary prostaglandins were modestly lower during celecoxib (P < 0.05). Urinary sodium excretion was greater (P < 0.01) during the HS diet (253 ± 10 vs 281 ± 27 mmol/24 h for PL vs CX2, respectively) compared with the LS diet (14 ± 3 vs 17 ± 7 mmol/24 h for PL vs CX2, respectively; P(drug) = 0.26). Celecoxib did not alter creatinine clearance (P > 0.50). Twenty-four hour mean arterial BP was similar during PL (87 ± 2 vs 87 ± 2 mmHg for LS and HS, respectively) and CX2 (88 ± 2 vs 87 ± 2 mmHg for LS and HS, respectively; P = 0.85), with no effect of dietary salt (P > 0.80). Plasma renin activity, angiotensin II and aldosterone were all suppressed with dietary salt loading (P < 0.05), with no effect of drug (P > 0.35). 4. In conclusion, blood pressure and renal function were not adversely affected by celecoxib, even during dietary salt loading. These findings support current guidelines suggesting minimal cardiovascular risks associated with short-term, low-dose use of celecoxib in young to middle-aged adults. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

  13. Influence of immune activation and inflammatory response on cardiovascular risk associated with the human immunodeficiency virus.

    PubMed

    Beltrán, Luis M; Rubio-Navarro, Alfonso; Amaro-Villalobos, Juan Manuel; Egido, Jesús; García-Puig, Juan; Moreno, Juan Antonio

    2015-01-01

    Patients infected with the human immunodeficiency virus (HIV) have an increased cardiovascular risk. Although initially this increased risk was attributed to metabolic alterations associated with antiretroviral treatment, in recent years, the attention has been focused on the HIV disease itself. Inflammation, immune system activation, and endothelial dysfunction facilitated by HIV infection have been identified as key factors in the development and progression of atherosclerosis. In this review, we describe the epidemiology and pathogenesis of cardiovascular disease in patients with HIV infection and summarize the latest knowledge on the relationship between traditional and novel inflammatory, immune activation, and endothelial dysfunction biomarkers on the cardiovascular risk associated with HIV infection.

  14. Synthetic cannabinoids found in "spice" products alter body temperature and cardiovascular parameters in conscious male rats.

    PubMed

    Schindler, Charles W; Gramling, Benjamin R; Justinova, Zuzana; Thorndike, Eric B; Baumann, Michael H

    2017-08-18

    The misuse of synthetic cannabinoids is a persistent public health concern. Because these drugs target the same cannabinoid receptors as the active ingredient of marijuana, Δ(9)-tetrahydrocannabinol (THC), we compared the effects of synthetic cannabinoids and THC on body temperature and cardiovascular parameters. Biotelemetry transmitters for the measurement of body temperature or blood pressure (BP) were surgically implanted into separate groups of male rats. THC and the synthetic cannabinoids CP55,940, JWH-018, AM2201 and XLR-11 were injected s.c., and rats were placed into isolation cubicles for 3h. THC and synthetic cannabinoids produced dose-related decreases in body temperature that were most prominent in the final 2h of the session. The rank order of potency was CP55,940>AM2201=JWH-018>THC=XLR-11. The cannabinoid inverse agonist rimonabant antagonized the hypothermic effect of all compounds. Synthetic cannabinoids elevated BP in comparison to vehicle treatment during the first h of the session, while heart rate was unaffected. The rank order of potency for BP increases was similar to that seen for hypothermia. Hypertensive effects of CP55,940 and JWH-018 were not antagonized by rimonabant or the neutral antagonist AM4113. However, the BP responses to both drugs were antagonized by pretreatment with either the ganglionic blocker hexamethonium or the α1 adrenergic antagonist prazosin. Our results show that synthetic cannabinoids produce hypothermia in rats by a mechanism involving cannabinoid receptors, while they increase BP by a mechanism independent of these sites. The hypertensive effect appears to involve central sympathetic outflow. Published by Elsevier B.V.

  15. Activated oxygen alters cerebral microvascular responses in newborn pigs

    SciTech Connect

    Leffler, C.W.; Busiia, D.W.; Armstead, W.M.; Mirro, R.; Thelin, O. )

    1990-02-26

    In piglets, cerebral ischemia/reperfusion blocks prostanoid dependent cerebral vasodilation to hypercapnia (CO{sub 2}) and hypotension but not prostanoid independent dilation to isoproterenol (Isu) or constriction to norepinephrine (NE). Ischemia/reperfusion increases activated-O{sub 2} production by piglet brains. Using cranial windows in piglets, the authors investigated the hypothesis that activated oxygen can block prostanoid dependent cerebral vasodilator responses to CO{sub 2} and hypotension without altering responses to Isu and NE. Exposure to an activated oxygen generating system of xanthine oxidase, hypoxanthine, and Fe that made about 3 times the activated-O{sub 2} on the brain surface as ischemia/reperfusion caused reversible pial arteriolar dilation. After exposure, pial arteriolar dilation was reduced to CO{sub 2} and hypotension but not to Isu. NE constrictor responses were also unaltered. H{sub 2}O{sub 2} or H{sub 2}O{sub 2} + Fe caused constriction followed by reversible dilation. After exposure, pial arteriolar dilation in response to CO{sub 2} and hypotension was not altered. However, addition of xanthine oxidase and hypoxanthine with H{sub 2}O{sub 2} and Fe totally eliminated pial arteriolar dilator responses to CO{sub 2} and hypotension but did not decrease dilation caused by Isu or constriction caused by NE. The authors conclude that activated oxygen could produce the altered prostanoid dependent pial arteriolar responses observed following ischemia in piglets.

  16. Serotoninergic Modulation of Basal Cardiovascular Responses and Responses Induced by Isotonic Extracellular Volume Expansion in Rats.

    PubMed

    Semionatto, Isadora Ferraz; Raminelli, Adrieli Oliveira; Alves, Angelica Cristina; Capitelli, Caroline Santos; Chriguer, Rosangela Soares

    2017-02-01

    Isotonic blood volume expansion (BVE) induced alterations of sympathetic and parasympathetic activity in the heart and blood vessels, which can be modulated by serotonergic pathways. To evaluate the effect of saline or serotonergic agonist (DOI) administration in the hypothalamic paraventricular nucleus (PVN) on cardiovascular responses after BVE. We recorded pulsatile blood pressure through the femoral artery to obtain the mean arterial pressure (MAP), systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and the sympathetic-vagal ratio (LF/HF) of Wistar rats before and after they received bilateral microinjections of saline or DOI into the PVN, followed by BVE. No significant differences were observed in the values of the studied variables in the different treatments from the control group. However, when animals are treated with DOI followed by BVE there is a significant increase in relation to the BE control group in all the studied variables: MBP (114.42±7.85 vs 101.34±9.17); SBP (147.23±14.31 vs 129.39±10.70); DBP (98.01 ±4.91 vs 87.31±8.61); HR (421.02±43.32 vs 356.35±41.99); and LF/HF ratio (2.32±0.80 vs 0.27±0.32). The present study showed that the induction of isotonic BVE did not promote alterations in MAP, HR and LF/HF ratio. On the other hand, the injection of DOI into PVN of the hypothalamus followed by isotonic BVE resulted in a significant increase of all variables. These results suggest that serotonin induced a neuromodulation in the PVN level, which promotes an inhibition of the baroreflex response to BVE. Therefore, the present study suggests the involvement of the serotonergic system in the modulation of vagal reflex response at PVN in the normotensive rats. Expansão de volume extracelular (EVEC) promove alterações da atividade simpática e parassimpática no coração e vasos sanguíneos, os quais podem ser moduladas por vias serotoninérgicas. Avaliar o efeito da administração de salina ou agonista serotonin

  17. Cardiovascular response to mental stress and to handgrip in children. The role of physical activity.

    PubMed

    Ferrara, L A; Mainenti, G; Fasano, M L; Marotta, T; Borrelli, R; Mancini, M

    1991-09-01

    Cardiovascular responses to sympathetic stimulation may be altered in the early phases of life of subjects with a family history of hypertension. The possible influence of physical activity on adrenergic modulation in children is still not well known. In this study we evaluated, in a group of 162 11-year-old children from a secondary school near Naples, blood pressure and heart rate measured 4 times at 3-week intervals at rest and during adrenergic system stimulation by mental arithmetic stress and isometric exercise. Children were divided into sedentary and physically active groups according to the levels of a Saltin modified questionnaire. Family history of hypertension was also investigated. Systolic and diastolic blood pressure at rest were slightly higher in the sedentary group at each control (107/75 +/- 11/11 vs 105/73 +/- 11/11 mmHg at the first and 100/70 +/- 14/14 vs 98/69 +/- 9/9 at the last control); heart rate in the same group was higher as well (91 +/- 11 vs 87 +/- 12 beats/min, p less than 0.02 at the first and 80 +/- 9 vs 77 +/- 11 at the last control). Systolic and diastolic blood pressure increased by 7/15% during mental stress and by 23/45% during isometric exercise in the sedentary group. The corresponding blood pressure increases in the physically active group were 6/12% and 20/40%, respectively. These responses were independent of sex, body weight and family history of hypertension. These results support the hypothesis that regular physical activity in young adolescents only mildly influences resting blood pressure and cardiovascular responses during the stimulation of the sympathetic nervous system.

  18. Hydrologic Alteration and Response of Ecosystem Functions to River Restoration

    NASA Astrophysics Data System (ADS)

    Orr, C. H.; Stanley, E. H.

    2005-12-01

    Stream ecology theory suggests that physical and hydrologic setting is often a dominant determinant of ecosystem structure in fluvial systems. Restorationist practitioners may work under the assumption that if the hydrologic parameters that control biological processes are restored, biotic components of interest should be restored as well. This method is sometimes called passive habitat restoration, or an eco-hydromorphic approach. An alternate to this hypothesis is that biological recovery is constrained by a number of other limitations such as distance to a source population, site history, and presence of invasive species. In this scenario, systems will not be restored by hydrologic alterations alone. To address the influence physical setting has on ecological process, we measured three specific ecological responses of streams to hydrologic manipulations separate restoration projects in Central Wisconsin. The projects shared the common trait of being primarily hydrologic alterations. We measured phosphorus retention capacity in a second-order stream before and after a pair of small dam removals, denitrification rates following the reflooding of a leveed floodplain and an approximately 50-year time series of vegetation recolonization on exposed mud flats following dam removal. In each case the measured responses showed unexpectedly large variability and there was not close correlation between physical and ecologic parameters. Such high variability in response to alterations also made it difficult to determine if the restorations met their goals. One conclusion of these studies may be that we need to move beyond hydrologic alterations to address additional manipulations to better meet the goals of specific projects.

  19. Role of Shp2 in forebrain neurons in regulating metabolic and cardiovascular functions and responses to leptin

    PubMed Central

    do Carmo, Jussara M.; da Silva, Alexandre A.; Sessums, Price O.; Ebaady, Sabira H.; Pace, Benjamin R.; Rushing, John S.; Davis, Mark T.; Hall, John E.

    2014-01-01

    Objective We examined whether deficiency of Shp2 signaling in forebrain neurons alters metabolic and cardiovascular regulation under various conditions and if it attenuates the anorexic and cardiovascular effects of leptin. We also tested whether forebrain Shp2 deficiency alters blood pressure (BP) and heart rate (HR) responses to acute stress. Design Forebrain Shp2-/- mice were generated by crossing Shp2flox/flox mice with CamKIIα-cre mice. At 22 to 24 weeks of age, mice were instrumented for telemetry for measurement of BP, HR and body temperature (BT). Oxygen consumption (VO2), energy expenditure and motor activity were monitored by indirect calorimetry. Results Shp2/CamKIIα-cre mice were heavier (46±3 vs 32±1 g), hyperglycemic, hyperleptinemic, hyperinsulinemic, and hyperphagic compared to Shp2flox/flox control mice. Shp2/CamKIIα-cre mice exhibited reduced food intake responses to fasting/refeeding and impaired regulation of BT when exposed to 15°C and 30°C ambient temperatures. Despite being obese and having many features of metabolic syndrome, Shp2/CamKIIα-cre mice had similar daily average BP and HR compared to Shp2flox/flox mice (112±2 vs 113±1 mmHg and 595±34 vs 650±40 bpm), but exhibited increased BP and HR responses to cold exposure and acute air-jet stress test. Leptin's ability to reduce food intake and to raise BP were markedly attenuated in Shp2/CamKIIα-cre mice. Conclusion These results suggest that forebrain Shp2 signaling regulates food intake, appetite responses to caloric deprivation, and thermogenic control of body temperature during variations in ambient temperature. Deficiency of Shp2 signaling in the forebrain is associated with augmented cardiovascular responses to cold and acute stress but attenuated BP responses to leptin. PMID:24030516

  20. Predicting in vivo cardiovascular properties of β-blockers from cellular assays: a quantitative comparison of cellular and cardiovascular pharmacological responses

    PubMed Central

    Baker, Jillian G.; Kemp, Philip; March, Julie; Fretwell, Laurice; Hill, Stephen J.; Gardiner, Sheila M.

    2011-01-01

    β-Adrenoceptor antagonists differ in their degree of partial agonism. In vitro assays have provided information on ligand affinity, selectivity, and intrinsic efficacy. However, the extent to which these properties are manifest in vivo is less clear. Conscious freely moving rats, instrumented for measurement of heart rate (β1; HR) and hindquarters vascular conductance (β2; HVC) were used to measure receptor selectivity and ligand efficacy in vivo. CGP 20712A caused a dose-dependent decrease in basal HR (P<0.05, ANOVA) at 5 doses between 6.7 and 670 μg/kg (i.v.) and shifted the dose-response curve for isoprenaline to higher agonist concentrations without altering HVC responses. In contrast, at doses of 67 μg/kg (i.v.) and above, ICI 118551 substantially reduced the HVC response to isoprenaline without affecting HR responses. ZD 7114, xamoterol, and bucindolol significantly increased basal HR (ΔHR: +122±12, +129±11, and +59±11 beats/min, respectively; n=6), whereas other β-blockers caused significant reductions (all at 2 mg/kg i.v.). The agonist effects of xamoterol and ZD 7114 were equivalent to that of the highest dose of isoprenaline. Bucindolol, however, significantly antagonized the response to the highest doses isoprenaline. An excellent correlation was obtained between in vivo and in vitro measures of β1-adrenoceptor efficacy (R2=0.93; P<0.0001).—Baker, J. G., Kemp, P., March, J., Fretwell, L., Hill, S. J., Gardiner, S. M. Predicting in vivo cardiovascular properties of β-blockers from cellular assays: a quantitative comparison of cellular and cardiovascular pharmacological responses. PMID:21865315

  1. CADDIS Volume 2. Sources, Stressors and Responses: Flow Alteration

    EPA Pesticide Factsheets

    Introduction to the flow alteration module, when to list flow alteration as a candidate cause, ways to measure flow alteration, simple and detailed conceptual model diagrams for flow alteration, flow alteration module references and literature reviews.

  2. Mathematical modeling of human cardiovascular system for simulation of orthostatic response

    NASA Technical Reports Server (NTRS)

    Melchior, F. M.; Srinivasan, R. S.; Charles, J. B.

    1992-01-01

    This paper deals with the short-term response of the human cardiovascular system to orthostatic stresses in the context of developing a mathematical model of the overall system. It discusses the physiological issues involved and how these issues have been handled in published cardiovascular models for simulation of orthostatic response. Most of the models are stimulus specific with no demonstrated capability for simulating the responses to orthostatic stimuli of different types. A comprehensive model incorporating all known phenomena related to cardiovascular regulation would greatly help to interpret the various orthostatic responses of the system in a consistent manner and to understand the interactions among its elements. This paper provides a framework for future efforts in mathematical modeling of the entire cardiovascular system.

  3. An experimental design for quantification of cardiovascular responses to music stimuli in humans.

    PubMed

    Chang, S-H; Luo, C-H; Yeh, T-L

    2004-01-01

    There have been several researches on the relationship between music and human physiological or psychological responses. However, there are cardiovascular index factors that have not been explored quantitatively due to the qualitative nature of acoustic stimuli. This study proposes and demonstrates an experimental design for quantification of cardiovascular responses to music stimuli in humans. The system comprises two components: a unit for generating and monitoring quantitative acoustic stimuli and a portable autonomic nervous system (ANS) analysis unit for quantitative recording and analysis of the cardiovascular responses. The experimental results indicate that the proposed system can exactly achieve the goal of full control and measurement for the music stimuli, and also effectively support many quantitative indices of cardiovascular response in humans. In addition, the analysis results are discussed and predicted in the future clinical research.

  4. Mathematical modeling of human cardiovascular system for simulation of orthostatic response

    NASA Technical Reports Server (NTRS)

    Melchior, F. M.; Srinivasan, R. S.; Charles, J. B.

    1992-01-01

    This paper deals with the short-term response of the human cardiovascular system to orthostatic stresses in the context of developing a mathematical model of the overall system. It discusses the physiological issues involved and how these issues have been handled in published cardiovascular models for simulation of orthostatic response. Most of the models are stimulus specific with no demonstrated capability for simulating the responses to orthostatic stimuli of different types. A comprehensive model incorporating all known phenomena related to cardiovascular regulation would greatly help to interpret the various orthostatic responses of the system in a consistent manner and to understand the interactions among its elements. This paper provides a framework for future efforts in mathematical modeling of the entire cardiovascular system.

  5. Neonatal nociception elevated baseline blood pressure and attenuated cardiovascular responsiveness to noxious stress in adult rats.

    PubMed

    Chu, Ya-Chun; Yang, Cheryl C H; Lin, Ho-Tien; Chen, Pin-Tarng; Chang, Kuang-Yi; Yang, Shun-Chin; Kuo, Terry B J

    2012-10-01

    Neonatal nociception has significant long-term effects on sensory perception in adult animals. Although neonatal adverse experience affect future responsiveness to stressors is documented, little is known about the involvement of early nociceptive experiences in the susceptibility to subsequent nociceptive stress exposure during adulthood. The aim of this study is to explore the developmental change in cardiovascular regulating activity in adult rats that had been subjected to neonatal nociceptive insults. To address this question, we treated neonatal rats with an intraplantar injection of saline (control) or carrageenan at postnatal day 1. The carrageenan-treated rats exhibited generalized hypoalgesia at basal state, and localized hyperalgesia after re-nociceptive challenge induced by intraplantar injections of complete Freund's adjuvant (CFA) as adults. Then we recorded baseline cardiovascular variables and 24-h responsiveness to an injection of CFA in the free-moving adult rats with telemetric technique. The carrageenan-treated rats showed significantly higher basal blood pressures (110.3±3.16 vs. control 97.0±4.28 mmHg). In control animals, baroreceptor reflex sensitivity (BRS) decreased, sympathetic vasomotor activity increased, and parasympathetic activity was inhibited after CFA injection. Blood pressure elevation was evident (107.0±2.75 vs. pre-injection 97.0±4.28 mmHg). Comparatively, the carrageenan-treated rats showed a higher BRS (BrrLF 1.03±0.09 vs. control 0.70±0.06 ms/mmHg) and higher parasympathetic activity [0.93±0.17 vs. control 0.32±0.02 ln(ms²)] after CFA injection. The change in blood pressure is negligible (111.9±4.05 vs. pre-injection 110.3±3.16 mmHg). Our research has shown that neonatal nociception alters future pain sensation, raises basal blood pressure level, and attenuates cardiovascular responsiveness to nociceptive stress in adult rats. Copyright © 2012 ISDN. Published by Elsevier Ltd. All rights reserved.

  6. Chronic arthritis and cardiovascular disease: altered blood parameters give rise to a prothrombotic propensity.

    PubMed

    Beinsberger, Jilke; Heemskerk, Johan W M; Cosemans, Judith M E M

    2014-12-01

    Rheumatoid arthritis, and to a lesser extent ankylosing spondylitis and psoriatic arthritis, associates with increased morbidity and mortality due to cardiovascular complications. We hypothesized that the increased risk of cardiovascular disease is reflected by changes in blood parameters that are compatible with a prothrombotic propensity. To substantiate this notion, we performed an extensive literature search identifying such parameters. A search through PubMed (1970-2013) was done to find primary articles with the following search terms: rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis or synovial fluid. These were combined with keywords reflecting processes of atherothrombosis: atherosclerosis, cardiovascular disease, coagulation, endothelial, fibrinolysis, mean platelet volume, microparticle, platelet, platelet count and mass, thrombosis, and thrombus. The published studies point to a multitude of blood-related processes that can contribute to a prothrombotic propensity in chronic inflammatory diseases. These include an increase in platelet mass; low-level platelet activation, enforced by interaction with leukocytes and the formation of proinflammatory cytokines; a locally activated endothelium; and an increased coagulant activity. Patient treatment with methotrexate or TNF-α blockers appears to result in normalization of several of these prothrombotic parameters. This analysis provides a first identification of the mechanisms by which inflammatory arthritis can aggravate cardiovascular disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Abnormal cardiovascular responses induced by localized high power microwave exposure

    SciTech Connect

    Lu, S.-T; Brown, D.O.; Johnson, C.E.; Mathur, S.P. ); Elson, E.C. )

    1992-05-01

    A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz and 16 Hz pulsemodulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in the neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power but not to the lower average power microwaves. Depression of pulse pressure, an indication of a decrease in stroke volume, and increased or decreased heart rate were noted in presence of whole-body hyperthermia. The cardiac output of those animals exposed to higher average power microwaves was considered to be below normal as hypothesized. Decreased cardiac output and normal mean arterial pressure resulted in an increase in the total peripheral resistance which was contrary to the anticipated thermal response of animals.

  8. Type A Behavior and Cardiovascular Responsivity in Preschoolers.

    ERIC Educational Resources Information Center

    Brown, Marie Scott; Tanner, Christine

    This study investigated Type A behavior in preschool children and its relation to cardiovascular reactivity. One hundred forty-four children from 3.5 to 6.5 years old were categorized by their teachers according to the Matthews Youth Test for Health (MYTH) as Type A, Mixed, or Type B. The children's pulse, pulse rate variability, and blood…

  9. Cardiovascular responses to energy drinks in a healthy population: The C-energy study.

    PubMed

    Kozik, Teri M; Shah, Sachin; Bhattacharyya, Mouchumi; Franklin, Teresa T; Connolly, Therese Farrell; Chien, Walter; Charos, George S; Pelter, Michele M

    2016-07-01

    Energy drink consumption has increased significantly over the past decade and is associated with greater than 20,000 emergency department visits per year. Most often these visits are due to cardiovascular complaints ranging from palpitations to cardiac arrest. To determine if energy drinks alter; blood pressure, electrolytes, activated bleeding time (ACT), and/or cardiac responses measured with a 12-lead electrocardiographic (ECG) Holter. Continuous ECG data was collected for five hours (30 minutes baseline and 4 hours post consumption [PC]). Subjects consumed 32 ounces of energy drink within one hour and data (vital signs and blood samples) was collected throughout the study period. Paired students t-test and a corresponding non-parametric test (Wilcoxon signed rank) were used for analysis of the data. Fourteen healthy young subjects were recruited (mean age 28.6 years). Systolic blood pressure (baseline=132, ±7.83; PC=151, ±11.21; P=.001); QTc interval (baseline=423, ±22.74; PC=503, ±24.56; P<.001); magnesium level (baseline 2.04, ± 0.09; PC=2.13, ±0.15; P=.05); and calcium level (baseline=9.31, ±.28; PC=9.52, ±.22; P=.018) significantly increased from baseline. While potassium and ACT fluctuated (some subjects increased their levels while others decreased) these changes were not significant. Eight of the fourteen subjects (57%) developed a QTc >500 milliseconds PC. Other T-wave changes were noted in 9/14 (64.3%) subjects PC. Energy drinks increased systolic blood pressure, altered electrolytes, and resulted in repolarization abnormalities. These physiological responses can lead to arrhythmias and other abnormal cardiac responses highlighting the importance that emergency room personnel assess for energy drink consumption and potential toxicity. Copyright © 2016. Published by Elsevier Inc.

  10. Fungal symbionts alter plant responses to global change.

    PubMed

    Kivlin, Stephanie N; Emery, Sarah M; Rudgers, Jennifer A

    2013-07-01

    While direct plant responses to global change have been well characterized, indirect plant responses to global change, via altered species interactions, have received less attention. Here, we examined how plants associated with four classes of fungal symbionts (class I leaf endophytes [EF], arbuscular mycorrhizal fungi [AMF], ectomycorrhizal fungi [ECM], and dark septate endophytes [DSE]) responded to four global change factors (enriched CO2, drought, N deposition, and warming). We performed a meta-analysis of 434 studies spanning 174 publications to search for generalizable trends in responses of plant-fungal symbioses to future environments. Specifically, we addressed the following questions: (1) Can fungal symbionts ameliorate responses of plants to global change? (2) Do fungal symbiont groups differ in the degree to which they modify plant response to global change? (3) Do particular global change factors affect plant-fungal symbioses more than others? In all global change scenarios, except elevated CO2, fungal symbionts significantly altered plant responses to global change. In most cases, fungal symbionts increased plant biomass in response to global change. However, increased N deposition reduced the benefits of symbiosis. Of the global change factors we considered, drought and N deposition resulted in the strongest fungal mediation of plant responses. Our analysis highlighted gaps in current knowledge for responses of particular fungal groups and revealed the importance of considering not only the nonadditive effects of multiple global change factors, but also the interactive effects of multiple fungal symbioses. Our results show that considering plant-fungal symbioses is critical to predicting ecosystem response to global change.

  11. Cardiovascular and hormonal (aldosterone) responses in a rat model which mimics responses to weightlessness

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, J. M.

    1984-01-01

    Cardiovascular responses and fluid/electrolyte shifts seen during spaceflight have been attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended, head-down tilt of 15-20 deg) is used to model these responses. This study documents that elevated blood pressures in AO rats are sustained for periods of up to seven days, compared with presuspension values. Increased blood pressures in AO rats suggests a specific response to AO positioning, potentially relatable to a cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured. Circulating aldosterone concentrations were seen to increase approximately 100 percent during seven days of AO suspension, concurrently with a pronounced natriuresis. These results suggest that aldosterone may not be involved in the long term regulation of increased Na(+) excretion in AO animals. These studies continue to show the usefulness of models for the development of animal protocols for space flight.

  12. Response-restriction analysis: II. Alteration of activity preferences.

    PubMed Central

    Hanley, Gregory P; Iwata, Brian A; Roscoe, Eileen M; Thompson, Rachel H; Lindberg, Jana S

    2003-01-01

    We used response-restriction (RR) assessments to identify the preferences of 7 individuals with mental retardation for a variety of vocational and leisure activities. We subsequently increased their engagement in nonpreferred activities using several procedures: response restriction per se versus a Premack-type contingency (Study 1), supplemental reinforcement for engagement in target activities (Study 2), and noncontingent pairing of reinforcers with nonpreferred activities (Study 3). Results indicated that preferences are not immutable and can be altered through a variety of relatively benign interventions and that the results of RR assessments may be helpful in determining which types of procedures may be most effective on an individual basis. PMID:12723867

  13. Differences in cardiovascular and central nervous system responses to periods of mental work with a break.

    PubMed

    Liu, Xinxin; Iwakiri, Kazuyuki; Sotoyama, Midori; Iwanaga, Koichi

    2013-01-01

    The purpose of the present study was to examine how an inserted break influences the cardiovascular and central nervous system responses during periods of mental work. Twelve males conducted two 20-min periods of mental work with a 3-min break between them. Cardiovascular and central nervous system responses were measured continuously. In comparison to the baseline, cardiovascular responses increased continuously even after the inserted break, while, on the contrary, central nervous system activity did not significantly increase during the work periods but relaxed during the break. The work performance increased during the second work period. These results suggest that the inserted break proposed by VDT guidelines in Japan was effective in relaxing the central nervous system but was insufficient to prevent the increase in cardiovascular load. The results also imply that taking rests frequently is important not only to maintaining performance but also to preventing cumulative physiological workloads.

  14. EFFECTS OF AEROBIC CONDITIONING ON CARDIOVASCULAR SYMPATHETIC RESPONSE TO AND RECOVERY FROM CHALLENGE

    PubMed Central

    Lindgren, M; Alex, C; Shapiro, PA; McKinley, PS; Brondolo, EN; Myers, MM; Choi, CJ; Lopez-Pintado, S; Sloan, RP

    2013-01-01

    Objective Exercise has widely-documented cardioprotective effects but the mechanisms behind these effects are still poorly understood. Here, we test the hypothesis that aerobic training lowers cardiovascular sympathetic responses to and speeds recovery from challenge. Methods We conducted a randomized controlled trial contrasting aerobic versus strength training on indices of cardiac (pre-ejection period, PEP) and vascular (low-frequency blood pressure variability, LF-BPV) sympathetic responses to and recovery from psychological and orthostatic challenge in 149 young, healthy and sedentary adults. Results Aerobic and strength training did not alter PEP or LF-BPV reactivity to or recovery from challenge. Conclusions These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on PEP and LF BPV reactivity to or recovery from psychological or orthostatic challenge. In healthy young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in sympathetic activity. PMID:23889039

  15. A Computational Model for Thrombus Formation in Response to Cardiovascular Implantable Devices

    NASA Astrophysics Data System (ADS)

    Horn, John; Ortega, Jason; Maitland, Duncan

    2014-11-01

    Cardiovascular implantable devices elicit complex physiological responses within blood. Notably, alterations in blood flow dynamics and interactions between blood proteins and biomaterial surface chemistry may lead to the formation of thrombus. For some devices, such as stents and heart valves, this is an adverse outcome. For other devices, such as embolic aneurysm treatments, efficient blood clot formation is desired. Thus a method to study how biomedical devices induce thrombosis is paramount to device development and optimization. A multiscale, multiphysics computational model is developed to predict thrombus formation within the vasculature. The model consists of a set of convection-diffusion-reaction partial differential equations for blood protein constituents involved in the progression of the clotting cascades. This model is used to study thrombus production from endovascular devices with the goal of optimizing the device design to generate the desired clotting response. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  16. Predictions of cardiovascular responses during STS reentry using mathematical models

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.; Srinivasan, R.

    1985-01-01

    The physiological adaptation to weightless exposure includes cardiovascular deconditioning arising in part from a loss of total circulating blood volume and resulting in a reduction of orthostatic tolerance. The crew of the Shuttle orbiter are less tolerant to acceleration forces in the head-to-foot direction during the reentry phase of the flight at a time they must function at a high level of performance. The factors that contribute to orthostatic intolerance during and following reentry and to predict the likelihood of impaired crew performance are evaluated. A computer simulation approach employing a mathematical model of the cardiovascular system is employed. It is shown that depending on the severity of blood volume loss, the reentry acceleration stress may be detrimental to physiologic function and may place the physiologic status of the crew near the borderline of some type of impairment. They are in agreement with conclusions from early ground-based experiments and from observations of early Shuttle flights.

  17. Coagulation defects and altered hemodynamic responses in mice lacking receptors for thromboxane A2.

    PubMed Central

    Thomas, D W; Mannon, R B; Mannon, P J; Latour, A; Oliver, J A; Hoffman, M; Smithies, O; Koller, B H; Coffman, T M

    1998-01-01

    Thromboxane A2 (TXA2) is a labile metabolite of arachidonic acid that has potent biological effects. Its actions are mediated by G protein-coupled thromboxane-prostanoid (TP) receptors. TP receptors have been implicated in the pathogenesis of cardiovascular diseases. To investigate the physiological functions of TP receptors, we generated TP receptor-deficient mice by gene targeting. Tp-/- animals reproduce and survive in expected numbers, and their major organ systems are normal. Thromboxane agonist binding cannot be detected in tissues from Tp-/- mice. Bleeding times are prolonged in Tp-/- mice and their platelets do not aggregate after exposure to TXA2 agonists. Aggregation responses after collagen stimulation are also delayed, although ADP-stimulated aggregation is normal. Infusion of the TP receptor agonist U-46619 causes transient increases in blood pressure followed by cardiovascular collapse in wild-type mice, but U-46619 caused no hemodynamic effect in Tp-/- mice. Tp-/- mice are also resistant to arachidonic acid-induced shock, although arachidonic acid signifi-cantly reduced blood pressure in Tp-/- mice. In summary, Tp-/- mice have a mild bleeding disorder and altered vascular responses to TXA2 and arachidonic acid. Our studies suggest that most of the recognized functions of TXA2 are mediated by the single known Tp gene locus. PMID:9835625

  18. Response of the Cardiovascular System to Vibration and Combined Stresses

    DTIC Science & Technology

    1983-11-30

    volunteers between the ages of 18 and 24. Subjects were required to fill out medical history question- V naires and were excluded on the basis of any...cardiovascular problems, history of motion sickness, acute illness of any kind, or any musculoskeletal problems. All subjects were carefully screened, and...ners with nonathletes, swimmers, and weightlifters using the same LBNP protocol. Very few differences in resting or LBNP-stressed parameters were

  19. Cardiovascular reflex responses after intrathecal omega-conotoxins or dexmedetomidine in the rabbit.

    PubMed

    Blake, Duncan W; Wright, Christine E; Scott, David A; Angus, James A

    2003-01-01

    1. The effects of thoracic intrathecal doses (1 microg/kg) of the alpha2-adrenoceptor agonist dexmedetomidine and omega-conotoxins MVIIA and CVID on vasoconstrictor and heart rate responses to acute central hypovolaemia were studied in seven chronically instrumented rabbits. 2. Gradual inflation of an inferior vena cava cuff to reduce cardiac index (CI) by 8% per minute induced progressive vasoconstriction and an increase in heart rate (phase I). At approximately 40% of resting CI, there was sudden decompensation with failure of vasoconstriction and decrease in mean arterial pressure (MAP; phase II). 3. Both intrathecal MVIIA and CVID decreased resting CI (by 20% at 3 h), but only MVIIA significantly reduced resting MAP (P = 0.003). Dexmedetomidine resulted in transient bradycardia, but no other significant change in the resting circulation. With simulated haemorrhage, the relationship between CI and vascular conductance was shifted after MVIIA (1-3 h after injection) so that there was less vasoconstriction and a reduced increase in heart rate by the end of phase I compared with other treatments (P = 0.002 and P = 0.009, respectively). One hour after injection, dexmedetomidine reduced the slope of the phase I vasoconstrictor response (P = 0.03), but did not significantly alter the end-point of the response. With failure of vasoconstriction and the onset of phase II, vascular conductance was higher after MVIIA compared with controls. Both conotoxins caused progressive failure of vasoconstriction rather than recovery during phase II (P < 0.001). 4. Intrathecal injections of these drugs to control chronic pain may compromise cardiovascular responses to changes in central blood volume. At the single doses studied, there were significant differences between the responses to simulated haemorrhage after MVIIA or dexmedetomidine compared with CVID, with the prolonged effect after MVIIA most likely to be of clinical significance.

  20. Altered thermoregulatory responses to clonidine in streptozotocin-diabetic rats.

    PubMed Central

    O'Donnell, J. M.; Banyasz, T.; Kovacs, T.

    1996-01-01

    1. The effects of streptozotocin (STZ) treatment on alpha 2-adrenoceptor regulation of body temperature were studied by monitoring the response of colonic temperature to administration of clonidine. 2. A dose-dependent fall in colonic temperature occurred in control rats given clonidine challenge (0.05-2.0 mg kg-1, s.c.); this response was inhibited by prior administration of either yohimbine or idazoxan (2 mg kg-1, s.c.) but not by the peripherally-acting alpha 2-adrenoceptor antagonist L-659,066 (10 mg kg-1, s.c.). 3. In rats treated with STZ (65 mg kg-1, i.v.) administration of clonidine elicited a dose-independent hyperthermia (circa 1 degree C.); this effect was unaltered by prior administration of yohimbine or idazoxan. 4. Naloxone (5 mg kg-1, s.c.) elicited a small fall in temperature (< 1 degree C.) in both control and STZ-treated rats; naloxone pretreatment did not alter the temperature response to clonidine in either group. 5. Nicotinic acid (10 mg kg-1, s.c.) caused a similar small elevation in temperature in both groups. 6. Administration of replacement insulin to STZ-treated rats maintained weight gain and low blood glucose while the thermoregulatory response to clonidine slowly reverted to normal. 7. These results show that altered central temperature control is an element of the generalised abnormality of alpha 2-receptor function induced by STZ. PMID:8851514

  1. An altered peripheral IL6 response in major depressive disorder

    PubMed Central

    Money, Kelli M.; Olah, Zita; Korade, Zeljka; Garbett, Krassimira A.; Shelton, Richard C.; Mirnics, Karoly

    2016-01-01

    Major depressive disorder (MDD) is one of the most prevalent major psychiatric disorders with a lifetime prevalence of 17%. Recent evidence suggests MDD is not only a brain dysfunction, but a systemic disease affecting the whole body. Central and peripheral inflammatory changes seem to be a centerpiece of MDD pathology: a subset of patients show elevated blood cytokine and chemokine levels that partially normalize with symptom improvement over the course of antidepressant treatment. As this inflammatory process in MDD is poorly understood, we hypothesized that the peripheral tissues of MDD patients will respond differently to inflammatory stimuli, resulting in an aberrant transcriptional response to elevated proinflammatory cytokines. To test this, we used MDD patient- and control-derived dermal fibroblast cultures to investigate their response to an acute treatment with IL6, IL1β, TNFα, or vehicle. Following RNA isolation and subsequent cDNA synthesis, quantitative PCR was used to determine the relative expression level of several families of inflammation-responsive genes. Our results showed comparable expression of the tested genes between MDD patients and controls at baseline. In contrast, MDD patient fibroblasts had a diminished transcriptional response to IL6 in all the gene sets tested (oxidative stress response, mitochondrial function, and lipid metabolism). We also found a significant increase in baseline and IL6 stimulated transcript levels of the IL6 receptor gene. This IL6 receptor transcript increase in MDD fibroblasts was accompanied by an IL6 stimulated increase in induction of SOCS3, which dampens IL6 receptor signaling. Altogether our results demonstrate that there is an altered transcriptional response to IL6 in MDD, which may represent one of the molecular mechanisms contributing to disease pathophysiology. Ultimately we hope that these studies will lead to validation of novel MDD drug targets focused on normalizing the altered IL6 response in

  2. An altered peripheral IL6 response in major depressive disorder.

    PubMed

    Money, Kelli M; Olah, Zita; Korade, Zeljka; Garbett, Krassimira A; Shelton, Richard C; Mirnics, Karoly

    2016-05-01

    Major depressive disorder (MDD) is one of the most prevalent major psychiatric disorders with a lifetime prevalence of 17%. Recent evidence suggests MDD is not only a brain dysfunction, but a systemic disease affecting the whole body. Central and peripheral inflammatory changes seem to be a centerpiece of MDD pathology: a subset of patients show elevated blood cytokine and chemokine levels that partially normalize with symptom improvement over the course of anti-depressant treatment. As this inflammatory process in MDD is poorly understood, we hypothesized that the peripheral tissues of MDD patients will respond differently to inflammatory stimuli, resulting in an aberrant transcriptional response to elevated pro-inflammatory cytokines. To test this, we used MDD patient- and control-derived dermal fibroblast cultures to investigate their response to an acute treatment with IL6, IL1β, TNFα, or vehicle. Following RNA isolation and subsequent cDNA synthesis, quantitative PCR was used to determine the relative expression level of several families of inflammation-responsive genes. Our results showed comparable expression of the tested genes between MDD patients and controls at baseline. In contrast, MDD patient fibroblasts had a diminished transcriptional response to IL6 in all the gene sets tested (oxidative stress response, mitochondrial function, and lipid metabolism). We also found a significant increase in baseline and IL6 stimulated transcript levels of the IL6 receptor gene. This IL6 receptor transcript increase in MDD fibroblasts was accompanied by an IL6 stimulated increase in induction of SOCS3, which dampens IL6 receptor signaling. Altogether our results demonstrate that there is an altered transcriptional response to IL6 in MDD, which may represent one of the molecular mechanisms contributing to disease pathophysiology. Ultimately we hope that these studies will lead to validation of novel MDD drug targets focused on normalizing the altered IL6 response in

  3. Curious cases: Altered dose-response relationships in addiction genetics.

    PubMed

    Uhl, George R; Drgonova, Jana; Hall, F Scott

    2014-03-01

    Dose-response relationships for most addictive substances are "inverted U"-shaped. Addictive substances produce both positive features that include reward, euphoria, anxiolysis, withdrawal-relief, and negative features that include aversion, dysphoria, anxiety and withdrawal symptoms. A simple model differentially associates ascending and descending limbs of dose-response curves with rewarding and aversive influences, respectively. However, Diagnostic and Statistical Manual (DSM) diagnoses of substance dependence fail to incorporate dose-response criteria and don't directly consider balances between euphoric and dysphoric drug effects. Classical genetic studies document substantial heritable influences on DSM substance dependence. Linkage and genome-wide association studies identify modest-sized effects at any locus. Nevertheless, clusters of SNPs within selected genes display 10(-2)>p>10(-8) associations with dependence in many independent samples. For several of these genes, evidence for cis-regulatory, level-of-expression differences supports the validity of mouse models in which levels of expression are also altered. This review documents surprising, recently defined cases in which convergent evidence from humans and mouse models supports central influences of altered dose-response relationships in mediating the impact of relevant genomic variation on addiction phenotypes. For variation at loci for the α5 nicotinic acetylcholine receptor, cadherin 13, receptor type protein tyrosine phosphatase Δ and neuronal cell adhesion molecule genes, changed dose-response relationships conferred by gene knockouts in mice are accompanied by supporting human data. These observations emphasize desirability of carefully elucidating dose-response relationships for both rewarding and aversive features of abused substances wherever possible. They motivate consideration of individual differences in dose-response relationships in addiction nosology and therapeutics. © 2013.

  4. Spectral analysis of resting cardiovascular variables and responses to oscillatory LBNP before and after 6 degree head dowm bedrest

    NASA Technical Reports Server (NTRS)

    Knapp, Charles F.; Evans, J. M.; Patwardhan, A.; Levenhagen, D.; Wang, M.; Charles, John B.

    1991-01-01

    A major focus of our research program is to develop noninvasive procedures for determining changes in cardiovascular function associated with the null gravity environment. We define changes in cardiovascular function to be (1) the result of the regulatory system operating at values different from 'normal' but with an overall control system basically unchanged by the null gravity exposure, or (2) the result of operating with a control system that has significantly different regulatory characteristics after an exposure. To this end, we have used a model of weightlessness that consisted of exposing humans to 2 hrs. in the launch position, followed by 20 hrs. of 6 deg head down bedrest. Our principal objective was to use this model to measure cardiovascular responses to the 6 deg head down bedrest protocol and to develop the most sensitive 'systems identification' procedure for indicating change. A second objective, related to future experiments, is to use the procedure in combination with experiments designed to determine the degree to which a regulatory pathway has been altered and to determine the mechanisms responsible for the changes.

  5. Accelerometer-determined physical activity and the cardiovascular response to mental stress in children.

    PubMed

    Spartano, Nicole L; Heffernan, Kevin S; Dumas, Amy K; Gump, Brooks B

    2017-01-01

    Cardiovascular reactivity has been associated with future hypertension and cardiovascular mortality. Higher physical activity (PA) has been associated with lower cardiovascular reactivity in adults, but little data is available in children. The purpose of this study was to examine the relationship between PA and cardiovascular reactivity to mental stress in children. Cross-sectional study. This study sample included children from the Oswego Lead Study (n=79, 46% female, 9-11 years old). Impedance cardiography was performed while children participated in a stress response protocol. Children were also asked to wear Actigraph accelerometers on their wrists for 3 days to measure intensity and duration of PA and sedentary time. In multivariable models, moderate to vigorous (MV) PA was associated with lower body mass index (BMI) percentile and lower total peripheral resistance (TPR) response to stress (beta=-0.025, p=0.02; beta=-0.009, p=0.05). After additional adjustment for BMI, MVPA was also associated with lower diastolic blood pressure response to stress (beta=-0.01, p=0.03). Total PA and sedentary time were not associated with BMI or cardiovascular responses to stress. A modest, inverse relation of PA to vascular reactivity to mental stress was observed in children. These data provide confirmatory evidence that the promotion of PA recommendations for children are important for cardiovascular health. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  6. Mitochondria DNA mutations cause sex-dependent development of hypertension and alterations in cardiovascular function.

    PubMed

    Golob, Mark J; Tian, Lian; Wang, Zhijie; Zimmerman, Todd A; Caneba, Christine A; Hacker, Timothy A; Song, Guoqing; Chesler, Naomi C

    2015-02-05

    Aging is associated with conduit artery stiffening that is a risk factor for and can precede hypertension and ventricular dysfunction. Increases in mitochondria DNA (mtDNA) frequency have been correlated with aging. Mice with a mutation in the encoding domain (D257A) of a proof-reading deficient version of mtDNA polymerase-γ (POLG) have musculoskeletal features of premature aging and a shortened lifespan. However, few studies using these mice have investigated the effects of mtDNA mutations on cardiovascular function. We hypothesized that the proof-reading deficient mtDNA POLG leads to arterial stiffening, hypertension, and ventricular hypertrophy. Ten to twelve month-old D257A mice (n=13) and age- and sex-matched wild-type controls (n=13) were catheterized for hemodynamic and ventricular function measurements. Left common carotid arteries (LCCA) were harvested for mechanical tests followed by histology. Male D257A mice had pulmonary and systemic hypertension, arterial stiffening, larger LCCA diameter (701±45 vs. 597±60μm), shorter LCCA axial length (8.96±0.56 vs. 10.10±0.80mm), and reduced hematocrit (29.1±6.1 vs. 41.3±8.1; all p<0.05). Male and female D257A mice had biventricular hypertrophy (p<0.05). Female D257A mice did not have significant increases in pressure or arterial stiffening, suggesting that the mechanisms of hypertension or arterial stiffening from mtDNA mutations differ based on sex. Our results lend insight into the mechanisms of age-related cardiovascular disease and may point to novel treatment strategies to address cardiovascular mortality in the elderly.

  7. Effect of Oxidative Stress on Cardiovascular System in Response to Gravity.

    PubMed

    Takahashi, Ken; Okumura, Hiroki; Guo, Rui; Naruse, Keiji

    2017-07-04

    Long-term habitation in space leads to physiological alterations such as bone loss, muscle atrophy, and cardiovascular deconditioning. Two predominant factors-namely space radiation and microgravity-have a crucial impact on oxidative stress in living organisms. Oxidative stress is also involved in the aging process, and plays important roles in the development of cardiovascular diseases including hypertension, left ventricular hypertrophy, and myocardial infarction. Here, we discuss the effects of space radiation, microgravity, and a combination of these two factors on oxidative stress. Future research may facilitate safer living in space by reducing the adverse effects of oxidative stress.

  8. Altered cardiovascular reactivity and osmoregulation during hyperosmotic stress in adult rats developmentally exposed to polybrominated diphenyl ethers (PBDEs)

    SciTech Connect

    Shah, Ashini; Coburn, Cary G.; Watson-Siriboe, Abena; Whitley, Rebecca; Shahidzadeh, Anoush; Gillard, Elizabeth R.; Nichol, Robert; Leon-Olea, Martha; Gaertner, Mark; Kodavanti, Prasada Rao S.

    2011-10-15

    Polybrominated diphenyl ethers (PBDEs) and the structurally similar chemicals polychlorinated biphenyls (PCBs) disrupt the function of multiple endocrine systems. PCBs and PBDEs disrupt the secretion of vasopressin (VP) from the hypothalamus during osmotic activation. Since the peripheral and central vasopressinergic axes are critical for osmotic and cardiovascular regulation, we examined whether perinatal PBDE exposure could impact these functions during physiological activation. Rats were perinatally dosed with a commercial PBDE mixture, DE-71. Dams were given 0 (corn oil control), 1.7 (low dose) or 30.6 mg/kg/day (high dose) in corn oil from gestational day (GD) 6 through postnatal day (PND) 21 by oral gavage. In the male offspring exposed to high dose PBDE plasma thyroxine and triiodothyronine levels were reduced at PND 21 and recovered to control levels by PND 60 when thyroid stimulating hormone levels were elevated. At 14-18 months of age, cardiovascular responses were measured in four groups of rats: Normal (Oil, normosmotic condition), Hyper (Oil, hyperosmotic stress), Hyper PBDE low (1.7 mg/kg/day DE-71 perinatally, hyperosmotic stress), and Hyper PBDE high (30.6 mg/kg/day DE-71 perinatally, hyperosmotic stress). Systolic blood pressure (BP), diastolic BP, and heart rate (HR) were determined using tail cuff sphygmomanometry and normalized to pretreatment values (baseline) measured under basal conditions. Hyperosmotic treatment yielded significant changes in systolic BP in PBDE exposed rats only. Hyper PBDE low and high dose rats showed 36.1 and 64.7% greater systolic BP responses at 3 h post hyperosmotic injection relative to pretreatment baseline, respectively. No treatment effects were measured for diastolic BP and HR. Hyper and Hyper PBDE rats showed increased mean plasma osmolality values by 45 min after injection relative to normosmotic controls. In contrast to Hyper rats, Hyper PBDE (high) rats showed a further increase in mean plasma osmolality at 3

  9. Excitatory amino acid receptors in the periaqueductal gray mediate the cardiovascular response evoked by activation of dorsomedial hypothalamic neurons.

    PubMed

    da Silva, L G; Menezes, R C A; Villela, D C; Fontes, M A P

    2006-01-01

    Neurons in the region of dorsomedial hypothalamus are involved in the organization of the physiological responses to emotional stress. We have recently shown that the cardiovascular response evoked by activation of dorsomedial hypothalamus neurons is largely dependent on a synaptic relay with the lateral/dorsolateral periaqueductal gray region. In this study, we aimed to investigate whether excitatory amino acid receptors at the lateral/dorsolateral periaqueductal gray region are involved in mediating the response evoked by activation of dorsomedial hypothalamus neurons. In conscious rats, the cardiovascular effects produced by microinjection of GABA(A) receptor antagonist, bicuculline methiodide into the dorsomedial hypothalamus were evaluated before and after injection of different excitatory amino acid antagonists into lateral/dorsolateral periaqueductal gray region. Pretreatment of lateral/dorsolateral periaqueductal gray region with the non-selective ionotropic excitatory amino acid receptor antagonist kynurenic acid or with the N-methyl-D-aspartate receptor-selective antagonist, MK-801, largely reduced the tachycardic and pressor effects evoked by activation of dorsomedial hypothalamus neurons by bicuculline methiodide microinjection (heart rate 90 and 74%; blood pressure 81 and 84%, respectively). The non-N-methyl-D-aspartate receptor-selective antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, did not alter the cardiovascular response evoked by dorsomedial hypothalamus activation. In an additional series of experiments, microinjection of the N-methyl-D-aspartate receptor agonist, N-methyl-D-aspartate, into the lateral/dorsolateral periaqueductal gray region, evoked an increase in heart rate and a pressor response that was accompanied by an increase in locomotor activity. These effects were not altered by pretreatment of lateral/dorsolateral periaqueductal gray region neurons with 6-cyano-7-nitroquinoxaline-2,3-dione but were completely abolished by MK-801

  10. Hostility and Anger Expression: Behavioral and Cardiovascular Responses to Mental Stress Among Cardiovascular Disease Patients

    DTIC Science & Technology

    2002-01-01

    blood pressure responses to a modified Stroop test were significantly higher among the five who had suffered a new cardiac event at follow up 39 to 64...Those who developed ischemia in response to a speech task and the Stroop task had significantly greater systemic vascular resistance compared to... response to a Stroop test (Goldberg et al., 1996). Ischemia assessed by cardiac perfusion measures Perfusion of the cardiac tissue has been assessed via

  11. Cardiovascular Response Identification Based on Nonlinear Support Vector Regression

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Su, Steven W.; Chan, Gregory S. H.; Celler, Branko G.; Cheng, Teddy M.; Savkin, Andrey V.

    This study experimentally investigates the relationships between central cardiovascular variables and oxygen uptake based on nonlinear analysis and modeling. Ten healthy subjects were studied using cycle-ergometry exercise tests with constant workloads ranging from 25 Watt to 125 Watt. Breath by breath gas exchange, heart rate, cardiac output, stroke volume and blood pressure were measured at each stage. The modeling results proved that the nonlinear modeling method (Support Vector Regression) outperforms traditional regression method (reducing Estimation Error between 59% and 80%, reducing Testing Error between 53% and 72%) and is the ideal approach in the modeling of physiological data, especially with small training data set.

  12. Alterations in vascular function in primary aldosteronism: a cardiovascular magnetic resonance imaging study.

    PubMed

    Mark, P B; Boyle, S; Zimmerli, L U; McQuarrie, E P; Delles, C; Freel, E M

    2014-02-01

    Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV). We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass. Subjects with PA had significantly lower aortic distensibility and higher PWV compared with EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including ageing. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular ageing. As expected, aortic distensibility and PWV were closely correlated. These results demonstrate that PA patients display increased arterial stiffness compared with EH, independent of vascular ageing. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.

  13. Cardiovascular responses of the anterior claustrum; its mechanism; contribution of medial prefrontal cortex.

    PubMed

    Hatam, Masoumeh; Sheybanifar, Mehrnoosh; Nasimi, Ali

    2013-12-01

    The anterior claustrum (CLa) has bilateral connections with the areas involved in cardiovascular regulation, though its role in cardiovascular control is not yet understood. This study was performed to find the cardiovascular responsive region of the CLa by stimulating all parts of the CLa with l-glutamate, and to find the possible mechanisms mediating its responses in urethane-anesthetized rats. We also investigated the possible involvement of the medial prefrontal cortex in the cardiovascular responses of the CLa. The effect of microinjection of l-glutamate (50-100 nl, 0.25 M) was tested throughout the Cla and only in one area at 2.7 mm rostral to bregma, 1.8-2.0 midline and 4.5-5.6mm vertical, significant decreases in arterial pressure were elicited (-21.71±2.1 mmHg, P<0.001, t-test) with no significant change in heart rate. Administration (i.v.) of the muscarinic receptor blocker, atropine, had no effect on the change in mean arterial pressure in response to glutamate stimulation, suggesting that the parasympathetic system was not involved in this response. However, administration (i.v.) of the nicotinic receptor blocker, hexamethonium dichloride abolished the depressor response to glutamate, suggesting that CLa stimulation decreases sympathetic outflow to the cardiovascular system. In addition, microinjection of the reversible synaptic blocker, cobalt chloride, into the medial prefrontal cortex greatly attenuated the depressor response elicited by microinjection of glut into the CLa. Thus for the first time, we found the cardiovascular responsive region of the anterior claustrum. Also we showed that its response is mediated through the medial prefrontal cortex. © 2013.

  14. Key ecological responses to nitrogen are altered by climate change

    NASA Astrophysics Data System (ADS)

    Greaver, T. L.; Clark, C. M.; Compton, J. E.; Vallano, D.; Talhelm, A. F.; Weaver, C. P.; Band, L. E.; Baron, J. S.; Davidson, E. A.; Tague, C. L.; Felker-Quinn, E.; Lynch, J. A.; Herrick, J. D.; Liu, L.; Goodale, C. L.; Novak, K. J.; Haeuber, R. A.

    2016-09-01

    Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

  15. Key ecological responses to nitrogen are altered by climate change

    USGS Publications Warehouse

    Greaver, T.L.; Clark, C.M.; Compton, J.E.; Vallano, D.; Talhelm, A. F.; Weaver, C.P.; Band, L.E.; Baron, J. S.; Davidson, E.A.; Tague, C.L.; Felker-Quinn, E.; Lynch, J.A.; Herrick, J.D.; Liu, L.; Goodale, C.L.; Novak, K. J.; Haeuber, R. A.

    2016-01-01

    Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

  16. Computational modelling and evaluation of cardiovascular response under pulsatile impeller pump support

    PubMed Central

    Shi, Yubing; Brown, Alistair G.; Lawford, Patricia V.; Arndt, Andreas; Nuesser, Peter; Hose, D. Rodney

    2011-01-01

    This study presents a numerical simulation of cardiovascular response in the heart failure condition under the support of a Berlin Heart INCOR impeller pump-type ventricular assist device (VAD). The model is implemented using the CellML modelling language. To investigate the potential of using the Berlin Heart INCOR impeller pump to produce physiologically meaningful arterial pulse pressure within the various physiological constraints, a series of VAD-assisted cardiovascular cases are studied, in which the pulsation ratio and the phase shift of the VAD motion profile are systematically changed to observe the cardiovascular responses in each of the studied cases. An optimization process is proposed, including the introduction of a cost function to balance the importance of the characteristic cardiovascular variables. Based on this cost function it is found that a pulsation ratio of 0.35 combined with a phase shift of 200° produces the optimal cardiovascular response, giving rise to a maximal arterial pulse pressure of 12.6 mm Hg without inducing regurgitant pump flow while keeping other characteristic cardiovascular variables within appropriate physiological ranges. PMID:22670203

  17. Cardiovascular response of rats exposed to 60-Hz electric fields

    SciTech Connect

    Hilton, D.I.; Phillips, R.D.

    1980-01-01

    Recently, it has been reported that exposure to high-strength electric fields can influence electrocardiogram (ECG) patterns, heart rates, and blood pressures in various species of animals. Our studies were designed to evaluate these reported effects and to help clarify some of the disagreement present in the literature. Various cardiovascular variables were measured in Sprague-Dawley rats exposed or sham-exposed to 60-Hz electric fields at 80 to 100 kV/m for periods up to four months. No significant differences in heart rates, ECG patterns, blood pressures, or vascular reactivity were observed between exposed and sham-exposed rats after 8 hours, 40 hours, 1 month, or 4 months of exposure. Our studies cannot be directly compared to the work of other investigators because of differences in animal species and electric-field characteristics. However, our failure to detect any cardiovascular changes may have been the result of (1) eliminating secondary field effects such as shocks, audible noise, corona, and ozone; (2) minimizing steady-state microcurrents between the mouth of the animal and watering devices; and (3) minimizing electric-field-induced vibration of the electrodes and animal cages.

  18. Training and cardiovascular responses from cigarette smoke exposure.

    PubMed

    de Sá, Felipe Gonçalves Dos Santos; da Mota, Gustavo Ribeiro; Sant'Ana, Paula Grippa; da Cunha, Márcia Regina Holanda; Marocolo, Moacir; Castardeli, Edson

    2014-12-31

    The aim of this study was to evaluate the early effect of the endurance training (ET) on systolic blood pressure (SBP), heart rate (HR) and rate pressure-product (RPP) after acute cigarette smoke exposure. Twenty male Wistar rats were randomly allocated into two groups: trained (TEx; n = 10) and control (CEx; n = 10), exposed to smoke. TEx rats undertook ET during 2 weeks (swimming, 5 days/week; 1 h/session) and CEx group was kept in sedentary lifestyle. After ET protocol both groups were exposed to cigarette smoke only once (total 1 h; 2 × 30 min with interval of 10 min between exposures; rate of 10 cigarettes/30 min). SBP, HR and RPP were measured after 2 weeks and just after (5 min) acute cigarette smoke (tail plethysmograph). All parameters did not differ (P > 0.05) between TEx (RPP = 45018 ± 1970 mmHg/bpm) and CEx (43695 ± 2579 mmHg/bpm) after ET protocol. However, all cardiovascular parameters increased (P < 0.05) only for CEx just after the cigarette smoke exposure. We concluded that ET can attenuate the aggression from acute smoking to cardiovascular system, with a few days of training and even with no chronic effect on these parameters at basal condition.

  19. I got it! Transient cardiovascular response to the perception of humor.

    PubMed

    Lackner, Helmut K; Weiss, Elisabeth M; Schulter, Günter; Hinghofer-Szalkay, Helmut; Samson, Andrea C; Papousek, Ilona

    2013-04-01

    The aim of the present study was to examine the transient cardiovascular response to the perception of humor, that is, the impact of the cognitive process of insight as well as the modulation of the response by the affective appraisal of the humor. To this end transient heart rate, stroke volume, cardiac output, and blood pressure responses were obtained in the immediate context of detecting the punch line in cartoons. Fine-grained analysis of the transient behavior of cardiovascular variables during viewing the cartoons was contrasted to non-humorous cartoon-like pictures. The detection of a punch line was accompanied by relative heart rate acceleration in conjunction with increased cardiac output, which was more pronounced the more amusing the cartoons were perceived. These results provide first evidence of the usefulness of cardiovascular variables for detecting the moment of insight and the quantification of the size of the emotional response accompanying it.

  20. Cardiovascular regulatory response to lower body negative pressure following blood volume loss

    NASA Technical Reports Server (NTRS)

    Shimizu, M.; Ghista, D. N.; Sandler, H.

    1979-01-01

    An attempt is made to explain the cardiovascular regulatory responses to lower body negative pressure (LBNP) stress, both in the absence of and following blood or plasma volume loss, the latter being factors regularly observed with short- or long-term recumbency or weightlessness and associated with resulting cardiovascular deconditioning. Analytical expressions are derived for the responses of mean venous pressure and blood volume pooled in the lower body due to LBNP. An analysis is presented for determining the HR change due to LBNP stress following blood volume loss. It is concluded that the reduced orthostatic tolerance following long-term space flight or recumbency can be mainly attributed to blood volume loss, and that the associated cardiovascular responses characterizing this orthostatic intolerance is elicited by the associated central venous pressure response.

  1. Cardiovascular Responses to Psychosocial Stress Reflect Motivation State in Adults Born at Extremely Low Birth Weight.

    PubMed

    Mathewson, Karen J; Pyhälä, Riikka; Hovi, Petteri; Räikkönen, Katri; Van Lieshout, Ryan J; Boyle, Michael H; Saigal, Saroj; Morrison, Katherine M; Kajantie, Eero; Schmidt, Louis A

    2015-01-01

    Background. Adults born extremely preterm appear to have more difficulty managing the stresses of early adulthood than their term-born peers. Objective. To examine the effects of being born at extremely low birth weight (ELBW; birth weight < 1000 g) versus at full term on cardiovascular responses to stress. Method. Cardiovascular responses were elicited during administration of a widely used laboratory stressor, the Trier Social Stress Test (TSST). Results. Term-born adults exhibited a larger decrease in total peripheral resistance and larger increase in cardiac output for TSST performance, reflecting greater resilience, than did ELBW adults. Furthermore, in ELBW participants but not controls, cardiovascular responses were correlated with anxiety, suggesting that their responses reflected feelings of stress. Conclusions. Skills-training and practice with relevant stressors may be necessary to increase the personal resources of ELBW participants for managing stress as they transition to adulthood.

  2. Cardiovascular Responses to Psychosocial Stress Reflect Motivation State in Adults Born at Extremely Low Birth Weight

    PubMed Central

    Pyhälä, Riikka; Hovi, Petteri; Räikkönen, Katri; Van Lieshout, Ryan J.; Boyle, Michael H.; Saigal, Saroj; Morrison, Katherine M.; Kajantie, Eero; Schmidt, Louis A.

    2015-01-01

    Background. Adults born extremely preterm appear to have more difficulty managing the stresses of early adulthood than their term-born peers. Objective. To examine the effects of being born at extremely low birth weight (ELBW; birth weight < 1000 g) versus at full term on cardiovascular responses to stress. Method. Cardiovascular responses were elicited during administration of a widely used laboratory stressor, the Trier Social Stress Test (TSST). Results. Term-born adults exhibited a larger decrease in total peripheral resistance and larger increase in cardiac output for TSST performance, reflecting greater resilience, than did ELBW adults. Furthermore, in ELBW participants but not controls, cardiovascular responses were correlated with anxiety, suggesting that their responses reflected feelings of stress. Conclusions. Skills-training and practice with relevant stressors may be necessary to increase the personal resources of ELBW participants for managing stress as they transition to adulthood. PMID:27335948

  3. Cardiovascular regulatory response to lower body negative pressure following blood volume loss

    NASA Technical Reports Server (NTRS)

    Shimizu, M.; Ghista, D. N.; Sandler, H.

    1979-01-01

    An attempt is made to explain the cardiovascular regulatory responses to lower body negative pressure (LBNP) stress, both in the absence of and following blood or plasma volume loss, the latter being factors regularly observed with short- or long-term recumbency or weightlessness and associated with resulting cardiovascular deconditioning. Analytical expressions are derived for the responses of mean venous pressure and blood volume pooled in the lower body due to LBNP. An analysis is presented for determining the HR change due to LBNP stress following blood volume loss. It is concluded that the reduced orthostatic tolerance following long-term space flight or recumbency can be mainly attributed to blood volume loss, and that the associated cardiovascular responses characterizing this orthostatic intolerance is elicited by the associated central venous pressure response.

  4. Produced water exposure alters bacterial response to biocides.

    PubMed

    Vikram, Amit; Lipus, Daniel; Bibby, Kyle

    2014-11-04

    Microbial activity during the holding and reuse of wastewater from hydraulic fracturing operations, termed produced water, may lead to issues with corrosion, sulfide release, and fouling. Biocides are applied to control biological activity, often with limited efficacy, which is typically attributed to chemical interactions with the produced water. However, it is unknown whether there is a biologically driven mechanism to biocide tolerance in produced water. Here, we demonstrate that produced water exposure results in an enhanced tolerance against the typically used biocide glutaraldehyde and increased susceptibility to the oxidative biocide hypochlorite in a native and a model bacteria and that this altered resistance is due to the salinity of the produced water. In addition, we elucidate the genetic response of the model organism Pseudomonas fluorescens to produced water exposure to provide a mechanistic interpretation of the altered biocide resistance. The RNA-seq data demonstrated the induction of genes involved in osmotic stress, energy production and conversion, membrane integrity, and protein transport following produced water exposure, which facilitates bacterial survival and alters biocide tolerance. Efforts to fundamentally understand biocide resistance mechanisms, which enable the optimization of biocide application, hold significant implications for greening of the fracturing process through encouraging produced water recycling. Specifically, these results suggest the necessity of optimizing biocide application at the level of individual shale plays, rather than historical experience, based upon produced water characteristics and salinity.

  5. Contribution of infralimbic cortex in the cardiovascular response to acute stress.

    PubMed

    Müller-Ribeiro, Flávia Camargos de Figueirêdo; Zaretsky, Dmitry V; Zaretskaia, Maria V; Santos, Robson A S; DiMicco, Joseph A; Fontes, Marco Antônio Peliky

    2012-09-15

    The infralimbic region of the medial prefrontal cortex (IL) modulates autonomic and neuroendocrine function via projections to subcortical structures involved in the response to stress. We evaluated the contribution of the IL to the cardiovascular response evoked by acute stress. Under anesthesia (80 mg/kg ketamine-11.5 mg/kg xylazine), rats were implanted with telemetry probes or arterial lines for recording heart rate and blood pressure. Guide cannulas were implanted to target the IL for microinjection of muscimol (100 pmol/100 nl), N-methyl-d-aspartate (NMDA) (6 pmol/100 nl), or vehicle (100 nl). Microinjection of muscimol, an agonist of GABA(A) receptors, into the IL had no effect on stress-evoked cardiovascular and thermogenic changes in any of the paradigms evaluated (cage switch, restraint plus air-jet noise, or air-jet stress). However, microinjection of the excitatory amino acid NMDA into the IL attenuated the pressor and tachycardic response to air-jet stress. Pretreatment with the selective NMDA antagonist dl-2-amino-5-phosphonopentanoic acid (AP-5, 100 pmol/100 nl) blocked the effect of NMDA on the cardiovascular response to air-jet stress. We conclude that 1) the IL region is not tonically involved in cardiovascular or thermogenic control during stress or under baseline conditions, and 2) activation of NMDA receptors in the IL can suppress the cardiovascular response to acute stress exposure.

  6. Contribution of infralimbic cortex in the cardiovascular response to acute stress

    PubMed Central

    Müller-Ribeiro, Flávia Camargos de Figueirêdo; Zaretsky, Dmitry V.; Zaretskaia, Maria V.; Santos, Robson A. S.; DiMicco, Joseph A.

    2012-01-01

    The infralimbic region of the medial prefrontal cortex (IL) modulates autonomic and neuroendocrine function via projections to subcortical structures involved in the response to stress. We evaluated the contribution of the IL to the cardiovascular response evoked by acute stress. Under anesthesia (80 mg/kg ketamine-11.5 mg/kg xylazine), rats were implanted with telemetry probes or arterial lines for recording heart rate and blood pressure. Guide cannulas were implanted to target the IL for microinjection of muscimol (100 pmol/100 nl), N-methyl-d-aspartate (NMDA) (6 pmol/100 nl), or vehicle (100 nl). Microinjection of muscimol, an agonist of GABAA receptors, into the IL had no effect on stress-evoked cardiovascular and thermogenic changes in any of the paradigms evaluated (cage switch, restraint plus air-jet noise, or air-jet stress). However, microinjection of the excitatory amino acid NMDA into the IL attenuated the pressor and tachycardic response to air-jet stress. Pretreatment with the selective NMDA antagonist dl-2-amino-5-phosphonopentanoic acid (AP-5, 100 pmol/100 nl) blocked the effect of NMDA on the cardiovascular response to air-jet stress. We conclude that 1) the IL region is not tonically involved in cardiovascular or thermogenic control during stress or under baseline conditions, and 2) activation of NMDA receptors in the IL can suppress the cardiovascular response to acute stress exposure. PMID:22785427

  7. Ageing and exercise training alter adrenergic vasomotor responses of rat skeletal muscle arterioles

    PubMed Central

    Donato, Anthony J; Lesniewski, Lisa A; Delp, Michael D

    2007-01-01

    Ageing is associated with increased leg vascular resistance and reductions in leg blood flow during rest and exercise, potentially predisposing older adults to a host of functional and cardiovascular complications. The purpose of these studies was to examine the effects and possible mechanisms of ageing and exercise training on arteriolar adrenergic vasoreactivity. Young and old male Fischer 344 rats were divided into young sedentary (YS), old sedentary (OS), young exercise-trained (YT) or old exercise-trained (OT) groups, where training consisted of chronic treadmill exercise. Isolated soleus (SOL) and gastrocnemius (GAS) muscle arterioles were studied in vitro. Responses to noradrenaline in endothelium-intact and endothelium-denuded arterioles, as well as during nitric oxide synthase (NOS) inhibition were determined. Vasodilator responses to isoproterenol and forskolin were also determined. Results: Noradrenaline-mediated vasoconstriction was increased in SOL arterioles with ageing, and exercise training in old rats attenuated α-adrenergic vasoconstriction in arterioles from both muscle types. Removal of the endothelium and NOS inhibition eliminated these ageing and training effects. Isoproterenol-mediated vasodilatation was impaired with ageing in SOL and GAS arterioles, and exercise training had little effect on this response. Forskolin-induced vasodilatation was not affected by age. The data demonstrate that ageing augments α-adrenergic vasoconstriction while exercise training attenuates this response, and both of these alterations are mediated through an endothelial α-receptor-NOS-signalling pathway. In contrast, ageing diminishes β-receptor-mediated vasodilatation, but this impairment is specific to the smooth muscle. These studies indicate that α- and β-adrenergic mechanisms may serve to increase systemic vascular resistance with ageing, and that the effects of exercise training on adrenergic vasomotor properties could contribute to the beneficial

  8. Effects of Sex and Gender on Adaptation to Space: Cardiovascular Alterations

    PubMed Central

    Bairey Merz, C. Noel; Barr, Yael; Fu, Qi; Gulati, Martha; Hughson, Richard; Levine, Benjamin D.; Mehran, Roxana; Stachenfeld, Nina; Wenger, Nanette K.

    2014-01-01

    Abstract Sex and gender differences in the cardiovascular adaptation to spaceflight were examined with the goal of optimizing the health and safety of male and female astronauts at the forefront of space exploration. Female astronauts are more susceptible to orthostatic intolerance after space flight; the visual impairment intracranial pressure syndrome predominates slightly in males. Since spaceflight simulates vascular aging, sex-specific effects on vascular endothelium and thrombotic risk warrant examination as predisposing factors to atherosclerosis, important as the current cohort of astronauts ages. Currently, 20% of astronauts are women, and the recently selected astronaut recruits are 50% women. Thus there should be expectation that future research will reflect the composition of the overall population to determine potential benefits or risks. This should apply both to clinical studies and to basic science research. PMID:25401939

  9. Effects of sex and gender on adaptation to space: cardiovascular alterations.

    PubMed

    Platts, Steven H; Bairey Merz, C Noel; Barr, Yael; Fu, Qi; Gulati, Martha; Hughson, Richard; Levine, Benjamin D; Mehran, Roxana; Stachenfeld, Nina; Wenger, Nanette K

    2014-11-01

    Sex and gender differences in the cardiovascular adaptation to spaceflight were examined with the goal of optimizing the health and safety of male and female astronauts at the forefront of space exploration. Female astronauts are more susceptible to orthostatic intolerance after space flight; the visual impairment intracranial pressure syndrome predominates slightly in males. Since spaceflight simulates vascular aging, sex-specific effects on vascular endothelium and thrombotic risk warrant examination as predisposing factors to atherosclerosis, important as the current cohort of astronauts ages. Currently, 20% of astronauts are women, and the recently selected astronaut recruits are 50% women. Thus there should be expectation that future research will reflect the composition of the overall population to determine potential benefits or risks. This should apply both to clinical studies and to basic science research.

  10. Does mental arithmetic before head up tilt have an effect on the orthostatic cardiovascular and hormonal responses?

    NASA Astrophysics Data System (ADS)

    Goswami, Nandu; Lackner, Helmut Karl; Papousek, Ilona; Montani, Jean-Pierre; Jezova, Daniela; Hinghofer-Szalkay, Helmut G.

    2011-05-01

    Passive head up tilt (HUT) and mental arithmetic (MA) are commonly used for providing mental and orthostatic challenges, respectively. In animal experiments, even a single exposure to a stressor has been shown to modify the response to subsequent stress stimulus. We investigated whether MA applied before HUT elicits synergistic responses in orthostatic heart rate (HR), cardiac output (CO), heart rate variability and arterial blood pressure. The 15 healthy young males were subjected to two randomized protocols: (a) HUT and (b) HUT preceded by MA, with sessions randomized and ≥2 weeks apart. Beat to beat continuous hemodynamic variables were measured and saliva samples taken for hormonal assay. HUT alone increased HR from 59±7 (baseline) to 80±10 bpm (mean±SD) and mean blood pressure (MBP) from 88±10 to 91±14 mmHg. HUT results after MA were not different from those with HUT alone. The activity of alpha amylase showed differences during the experiments irrespective of the protocols. We conclude that mental challenge does not affect orthostatic cardiovascular responses when applied before; the timing of mental loading seems to be critical if it is intended to alter cardiovascular responses to upright standing.

  11. Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors

    EPA Science Inventory

    Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

  12. Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors

    EPA Science Inventory

    Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

  13. Contrasted monazite and allanite crystalline lattice responses under hydrothermal alteration

    NASA Astrophysics Data System (ADS)

    Poitrasson, F.

    2004-05-01

    Various cases of monazite and allanite hydrothermal alteration have been studied using micro-imaging (BSE-SEM), in situ spectroscopic (micro-Raman) and in situ chemical approaches (electron microprobe and LA-ICP-MS). These data, combined with literature results lead to the conclusion that monazite displays much more variable responses to fluid-mineral interactions than allanite despite a much simpler crystallographic structure. Depending on the fluid-rock conditions, monazite alteration can translate into cationic substitutions, monoclinic to hexagonal structure transition, dissolution and replacement by allanite, selective thorium removal and replacement by pyrite or dissolution-reprecipitation. In contrast, allanite responses to alteration are rather limited since they consist mostly in the substitution leading to epidote or to the leaching of the A-crystallographic sites prior to mineral dissolution. These results are surprising since monazite has only on cationic site besides that of phosphorous, whereas allanite has six different types of crystallographic sites, and can thus potentially display more variable chemical exchanges with fluids than monazite. This finding can be put in perspective with the tendency of minerals to occur in the metamict state in nature. Silicates, like zircon and allanite are frequently found in such a state, whereas metamict phosphates, like monazite and apatite are rare. It has been shown that this results mostly from the very low annealing temperature, below 200oC, of monazite and apatite, compared to allanite and zircon which need temperatures in excess to 700oC to fully restore their crystal lattice from the amorphous state. Apatite, like monazite, can also show a lot of different cationic substitutions. All these properties can be summarised as a much greater flexibility of the phosphate crystalline lattices compared to the silicate ones and this has important implications for geochronology, fluid-mineral chemical exchanges and

  14. Innate immune responses of Drosophila melanogaster are altered by spaceflight.

    PubMed

    Marcu, Oana; Lera, Matthew P; Sanchez, Max E; Levic, Edina; Higgins, Laura A; Shmygelska, Alena; Fahlen, Thomas F; Nichol, Helen; Bhattacharya, Sharmila

    2011-01-11

    Alterations and impairment of immune responses in humans present a health risk for space exploration missions. The molecular mechanisms underpinning innate immune defense can be confounded by the complexity of the acquired immune system of humans. Drosophila (fruit fly) innate immunity is simpler, and shares many similarities with human innate immunity at the level of molecular and genetic pathways. The goals of this study were to elucidate fundamental immune processes in Drosophila affected by spaceflight and to measure host-pathogen responses post-flight. Five containers, each containing ten female and five male fruit flies, were housed and bred on the space shuttle (average orbit altitude of 330.35 km) for 12 days and 18.5 hours. A new generation of flies was reared in microgravity. In larvae, the immune system was examined by analyzing plasmatocyte number and activity in culture. In adults, the induced immune responses were analyzed by bacterial clearance and quantitative real-time polymerase chain reaction (qPCR) of selected genes following infection with E. coli. The RNA levels of relevant immune pathway genes were determined in both larvae and adults by microarray analysis. The ability of larval plasmatocytes to phagocytose E. coli in culture was attenuated following spaceflight, and in parallel, the expression of genes involved in cell maturation was downregulated. In addition, the level of constitutive expression of pattern recognition receptors and opsonins that specifically recognize bacteria, and of lysozymes, antimicrobial peptide (AMP) pathway and immune stress genes, hallmarks of humoral immunity, were also reduced in larvae. In adults, the efficiency of bacterial clearance measured in vivo following a systemic infection with E. coli post-flight, remained robust. We show that spaceflight altered both cellular and humoral immune responses in Drosophila and that the disruption occurs at multiple interacting pathways.

  15. Innate Immune Responses of Drosophila melanogaster Are Altered by Spaceflight

    PubMed Central

    Marcu, Oana; Lera, Matthew P.; Sanchez, Max E.; Levic, Edina; Higgins, Laura A.; Shmygelska, Alena; Fahlen, Thomas F.; Nichol, Helen; Bhattacharya, Sharmila

    2011-01-01

    Alterations and impairment of immune responses in humans present a health risk for space exploration missions. The molecular mechanisms underpinning innate immune defense can be confounded by the complexity of the acquired immune system of humans. Drosophila (fruit fly) innate immunity is simpler, and shares many similarities with human innate immunity at the level of molecular and genetic pathways. The goals of this study were to elucidate fundamental immune processes in Drosophila affected by spaceflight and to measure host-pathogen responses post-flight. Five containers, each containing ten female and five male fruit flies, were housed and bred on the space shuttle (average orbit altitude of 330.35 km) for 12 days and 18.5 hours. A new generation of flies was reared in microgravity. In larvae, the immune system was examined by analyzing plasmatocyte number and activity in culture. In adults, the induced immune responses were analyzed by bacterial clearance and quantitative real-time polymerase chain reaction (qPCR) of selected genes following infection with E. coli. The RNA levels of relevant immune pathway genes were determined in both larvae and adults by microarray analysis. The ability of larval plasmatocytes to phagocytose E. coli in culture was attenuated following spaceflight, and in parallel, the expression of genes involved in cell maturation was downregulated. In addition, the level of constitutive expression of pattern recognition receptors and opsonins that specifically recognize bacteria, and of lysozymes, antimicrobial peptide (AMP) pathway and immune stress genes, hallmarks of humoral immunity, were also reduced in larvae. In adults, the efficiency of bacterial clearance measured in vivo following a systemic infection with E. coli post-flight, remained robust. We show that spaceflight altered both cellular and humoral immune responses in Drosophila and that the disruption occurs at multiple interacting pathways. PMID:21264297

  16. Prolonged prenatal psychotropic medication exposure alters neonatal acute pain response.

    PubMed

    Oberlander, Tim F; Eckstein Grunau, Ruth; Fitzgerald, Colleen; Ellwood, Ann-Louise; Misri, Shaila; Rurak, Dan; Riggs, Kenneth Wayne

    2002-04-01

    Selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines are frequently used to treat maternal depression during pregnancy, however the effect of increased serotonin (5HT) and gamma-amino-butyric acid (GABA) agonists in the fetal human brain remains unknown. 5HT and GABA are active during fetal neurologic growth and play early roles in pain modulation, therefore, if prolonged prenatal exposure alters neurodevelopment this may become evident in altered neonatal pain responses. To examine biologic and behavioral effects of prenatal exposure, neonatal responses to acute pain (phenylketonuria heel lance) in infants with prolonged prenatal exposure were examined. Facial action (Neonatal Facial Coding System) and cardiac autonomic reactivity derived from the relationship between respiratory activity and short term variations of heart rate (HRV) were compared between 22 infants with SSRI exposure (SE) [fluoxetine (n = 7), paroxetine (n = 11), sertraline (n = 4)]; 16 infants exposed to SSRIs and clonazepam (SE+) [paroxetine (n = 14), fluoxetine (n = 2)]; and 23 nonexposed infants during baseline, lance, and recovery periods of a heel lance. Length of maternal SSRI use did not vary significantly between exposure groups-[mean (range)] SE:SE+ 183 (31-281):141 (54-282) d (p > 0.05). Infants exposed to SE and SE+ displayed significantly less facial activity to heel lance than control infants. Mean HR increased with lance, but was significantly lower in SE infants during recovery. Using measures of HRV and the transfer relationship between heart rate and respiration, SSRI infants had a greater return of parasympathetic cardiac modulation in the recovery period, whereas a sustained sympathetic response continued in the control group. Prolonged prenatal SSRI exposure appears to be associated with reduced behavioral pain responses and increased parasympathetic cardiac modulation in recovery following an acute neonatal noxious event. Possible 5HT-mediated pain inhibition

  17. Mycorrhizal species differentially alter plant growth and response to herbivory.

    PubMed

    Bennett, Alison E; Bever, James D

    2007-01-01

    Plants simultaneously interact with multiple organisms which can both positively and negatively affect their growth. Herbivores can reduce plant growth through loss of plant biomass and photosynthetic area, while plant mutualists, such as mycorrhizal fungi, can increase plant growth through uptake of essential nutrients. This is the first study examining whether species-specific associations with mycorrhizal fungi alter plant tolerance to herbivory. We grew Plantago lanceolata plants with three species of mycorrhizal fungi previously shown to have differential impacts on plant growth and subjected them to herbivory by the specialist lepidopteran herbivore, Junonia coenia. Association with mycorrhizal fungus Glomus white provided the greatest growth benefit but did not alter plant response to herbivory. Alternatively, association with Archaeospora trappei provided less growth promotion but did lead to tolerance to herbivory in the form of an increased growth rate. Finally, an association with the fungus Scutellospora calospora led to neither plant growth promotion nor tolerance to herbivory. In fact, an association with S. calospora appeared to reduce plant tolerance to herbivory. An association with all three species of mycorrhizae resulted in a pattern of growth similar to that of plants grown only with Glomus white, suggesting that growth promotion by multiple mycorrhizal species is driven by the inclusion of a "super fungus," in this case, Glomus white. This work illustrates that plant response to herbivory depends upon the mycorrhizal fungal mutualist with which a plant is associated.

  18. Sulforaphane ameliorates the insulin responsiveness and the lipid profile but does not alter the antioxidant response in diabetic rats.

    PubMed

    de Souza, Carolina Guerini; da Motta, Leonardo Lisbôa; de Assis, Adriano Martimbianco; Rech, Anderson; Bruch, Ricardo; Klamt, Fábio; Souza, Diogo Onofre

    2016-04-01

    Diabetes is one of the most prevalent chronic non-communicable diseases and is characterized by hyperglycemia and increased oxidative stress. These two alterations are also responsible for the main diabetic complications: cardiovascular disease, retinopathy, nephropathy and peripheral neuropathy. Diabetes progression is governed by pancreatic β-cell failure, and recent studies showed that sulforaphane (SFN) might be able to prevent this change, preserving insulin production. Consequently, our goal was to test the effects of SFN on metabolic parameters related to diabetic complications and antioxidant defenses (superoxide dismutase, catalase and sulfhydryl groups) in the pancreas, liver and kidney of non-diabetic and diabetic rats. Male Wistar rats were treated with water or 0.5 mg kg(-1) SFN i.p. for 21 days after diabetes induction. In diabetic animals treated with SFN, the serum levels of total cholesterol, non-HDL cholesterol and triacylglycerols were similar to those of non-diabetic animals, and the insulin responsiveness was higher than that of the diabetic animals that did not receive the compound. No effect of SFN on the superoxide dismutase and catalase activity or sulfhydryl groups was observed in the pancreas, liver or kidney of the treated animals. We conclude that SFN ameliorates some features of clinical diabetic complications particularly the lipid profile and insulin responsiveness, but it does not modulate the antioxidant response induced by superoxide dismutase, catalase and sulfhydryl groups in the evaluated organs.

  19. Fish consumption and cardiovascular response during mental stress

    PubMed Central

    2012-01-01

    Background Frequent fish consumption is related to a lower risk of coronary heart disease. However, the physiological mechanisms underlying this cardioprotective effect are as yet unknown. We therefore examined certain cardiovascular physiological variables of fish eaters during rest, whilst conducting mental arithmetic, and during recovery. Findings The participants were 12 fish eaters (eating baked fish more than 3–4 times/week) and 13 controls (eating fish less than 1–2 times/week). Analysis of the collected data revealed that heart rate, blood pressure, and pulse wave velocity were significantly lower and pre-ejection period and baroreflex sensitivity were significantly higher in the fish eaters than in the controls during both rest and mental arithmetic, and that systolic and mean blood pressure recovery from mental arithmetic were faster in the fish eaters than in the controls. Conclusions These findings suggest a possible physiological mechanism that may explain why frequent fish consumption reduces coronary heart disease risk. PMID:22695000

  20. Maternal and fetal cardiovascular response to exercise during pregnancy.

    PubMed

    Veille, J C

    1996-08-01

    With the two-dimensional Doppler echocardiogram and M-mode echocardiogram, one can study maternal and fetal cardiovascular physiology during rest and exercise. Using such noninvasive techniques, studies indicate that left ventricular function is maintained even during vigorous bicycle exercise in healthy pregnant subjects during the second half of pregnancy. In early pregnancy, the left ventricle adapts to strenuous bicycle exercise by increasing its contractile reserve, enhancing ventricular emptying, whereas in late pregnancy, the left ventricle increases its preload reserve without significantly increasing its contractile reserve. Thus, women are "cardiovascularly" disadvantaged early in pregnancy. Using Doppler signals, early (E-passive) flow and late peak (A-active) flow reflect left ventricular diastolic filling properties. Using such techniques, we found that diastolic filling patterns are significantly influenced by pregnancy and that each trimester influences these diastolic filling patterns during upright bicycle exercise. Doppler studies of uteroplacental circulation during or after exercise have yielded conflicting results. Some have described an increase in "the vascular resistance" of this pelvic bed during strenuous exercise, whereas others have not. It seems safe to conclude that more studies are needed to elucidate this problem. Exercise does not seem to influence the resistivity index of the umbilical artery in either singleton or twins, and may even cause it to decrease. Ventricular diastolic filling properties of the fetal heart do not seem to be influenced by maternal bicycle exercise. Further studies are needed to determine if less active pregnant subjects, women with chronic hypertensive disorders, women with sickle cell anemia, or women with insulin-dependent diabetes adapt to exercise as well as their "normal" counterparts.

  1. Psychophysiological stress testing in postinfarction patients. Psychological correlates of cardiovascular arousal and abnormal cardiac responses.

    PubMed

    Zotti, A M; Bettinardi, O; Soffiantino, F; Tavazzi, L; Steptoe, A

    1991-04-01

    The psychophysiological responses to two mental stress tests (mental arithmetic and an interactive concentration task) were assessed in 168 unmedicated, male, postinfarction patients 36-69 years old. Patients also completed a standard battery of psychological tests. Psychophysiological responses were generally unrelated to age and education. Comparison of patients scoring high (more than 75%) and low (less than 25%) relative to the normal population on psychological measures indicated that heart rate and blood pressure responses to mental stress tests were significantly greater in those reporting low than in those reporting high neuroticism. The study population was subsequently divided into high, medium, and low cardiovascular responders on the basis of rate-pressure product reactions to the two stress tests. The three cardiovascular response groups did not differ in age, interval between myocardial infarction and stress testing, ejection fraction, incidence of exercise-induced ischemia, or ischemic signs during Holter monitoring. However, the high cardiovascular responders were more likely to manifest possible or definite electrocardiographic signs of ischemia or significant arrhythmia during mental stress testing than were the medium or low cardiovascular responders (50% versus 19.6% and 7%, respectively). High cardiovascular responders also reported lower levels of trait anxiety, neuroticism, psychophysiological symptoms, and depression.

  2. Emotion suppression affects cardiovascular responses to initial and subsequent laboratory stressors.

    PubMed

    Quartana, Phillip J; Burns, John W

    2010-09-01

    The study of anger suppression and risk for cardiovascular disease has relied predominately on inspection of correlations between trait anger-in and cardiovascular risk factors and disease. This approach tells us little about whether inhibitory processes have anything to do with outcomes, and cannot speak to whether suppression of anger per se affects cardiovascular parameters. Drawing on the broader emotion regulation literature, we examined the effects of experimentally induced anger and general negative emotion in the context of expressive and experiential suppression on cardiovascular responses to initial and subsequent laboratory stressors. Of all participants, 201 healthy participants were randomly assigned to one of six conditions formed by crossing emotion (anxiety, anger) and suppression (experiential, expressive, control) conditions. Participants completed a mental arithmetic task with anxiety or anger induction under their respective suppression manipulation instructions, and subsequently were exposed to a cold pressor task. Systolic blood pressure (SBP), diastolic blood pressure, and heart rate values were obtained for each experimental epoch. More robust SBP responses to the initial stressor were evidenced for those in the expressive versus the control condition. In response to the subsequent stressor, those in the experiential suppression condition showed the most pronounced SBP responses, suggesting pronounced delayed effects of this type of suppression. Effects of suppression on SBP reactivity were indistinguishable across anxiety and anger conditions. Effortful suppression of negative emotion has immediate and delayed consequences for stress-induced cardiovascular reactivity. Theoretical and clinical significance of these findings are discussed.

  3. Trait dominance is associated with vascular cardiovascular responses, and attenuated habituation, to social stress.

    PubMed

    Lee, Eimear M; Hughes, Brian M

    2014-05-01

    Both exaggerated and diminished levels of cardiovascular reactivity have been associated with cardiovascular ill health. Dysregulation of hemodynamic mechanisms which control cardiovascular functioning may account for some individual differences in health outcomes. Trait dominance has also been associated with poor cardiovascular health in studies of humans and animals. The current study investigated the relationship between trait dominance and cardiovascular habituation to repeated social stress in humans. Forty-seven undergraduate women completed two consecutive speech tasks, preceded by a baseline period, and separated by an inter-task resting phase. Continuous cardiovascular functioning was monitored using the Finometer device. The trait dominance subscale of the Jackson Personality Research Form was completed. Mixed ANCOVA with trait dominance revealed a significant 3 (dominance) × 4 (phase) interaction for total peripheral resistance (TPR), such that TPR varied across experimental phases and was associated with trait dominance, F(1, 43)=12.88, p=.001, partial η(2)=.23. Further mixed ANCOVA for TPR reactivity to Exposures 1 and 2 revealed a significant 3 × 2 interaction with trait dominance, F(2, 40)=7.77, p=.001, partial η(2)=.28, such that higher dominance was associated with attenuated TPR habituation to Exposure 2. Trait dominance was significantly associated with vascular-oriented cardiovascular functioning, and with attenuated habituation to social stress. Vascular-dominated stress responses have in some instances been associated with ill-health, suggesting that a failure to habituate to stress, and a vascular response style could reflect potential mechanisms through which dominance is associated with poor future cardiovascular health. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Altered Nitric Oxide Bioavailability Contributes to Diesel Exhaust Inhalation‐Induced Cardiovascular Dysfunction in Man

    PubMed Central

    Langrish, Jeremy P.; Unosson, Jon; Bosson, Jenny; Barath, Stefan; Muala, Ala; Blackwell, Scott; Söderberg, Stefan; Pourazar, Jamshid; Megson, Ian L.; Treweeke, Andrew; Sandström, Thomas; Newby, David E.; Blomberg, Anders; Mills, Nicholas L.

    2013-01-01

    Background Diesel exhaust inhalation causes cardiovascular dysfunction including impaired vascular reactivity, increased blood pressure, and arterial stiffness. We investigated the role of nitric oxide (NO) bioavailability in mediating these effects. Methods and Results In 2 randomized double‐blind crossover studies, healthy nonsmokers were exposed to diesel exhaust or filtered air. Study 1: Bilateral forearm blood flow was measured during intrabrachial infusions of acetylcholine (ACh; 5 to 20 μg/min) and sodium nitroprusside (SNP; 2 to 8 μg/min) in the presence of the NO clamp (NO synthase inhibitor NG‐monomethyl‐l‐arginine (l‐NMMA) 8 μg/min coinfused with the NO donor SNP at 90 to 540 ng/min to restore basal blood flow). Study 2: Blood pressure, arterial stiffness, and cardiac output were measured during systemic NO synthase inhibition with intravenous l‐NMMA (3 mg/kg). Following diesel exhaust inhalation, plasma nitrite concentrations were increased (68±48 versus 41±32 nmol/L; P=0.006) despite similar l‐NMMA–induced reductions in basal blood flow (−20.6±14.7% versus −21.1±14.6%; P=0.559) compared to air. In the presence of the NO clamp, ACh and SNP caused dose‐dependent vasodilatation that was not affected by diesel exhaust inhalation (P>0.05 for both). Following exposure to diesel exhaust, l‐NMMA caused a greater increase in blood pressure (P=0.048) and central arterial stiffness (P=0.007), but reductions in cardiac output and increases in systemic vascular resistance (P>0.05 for both) were similar to those seen with filtered air. Conclusions Diesel exhaust inhalation disturbs normal vascular homeostasis with enhanced NO generation unable to compensate for excess consumption. We suggest the adverse cardiovascular effects of air pollution are, in part, mediated through reduced NO bioavailability. Clinical Trial Registration URL: http://www.ClinicalTrials.gov. Unique identifiers: NCT00845767 and NCT01060930. PMID:23525434

  5. Histamine in the posterodorsal medial amygdala modulates cardiovascular reflex responses in awake rats.

    PubMed

    Quagliotto, E; Neckel, H; Riveiro, D F; Casali, K R; Mostarda, C; Irigoyen, M C; Dall'ago, P; Rasia-Filho, A A

    2008-12-10

    Centrally injected histamine (HA) affects heart rate (HR), arterial blood pressure (BP), and sympathetic activity in rats. The posterodorsal medial amygdala (MePD) has high levels of histidine decarboxylase, connections with brain areas involved with the modulation of cardiovascular responses, and is relevant for the pathogenesis of hypertension. However, there is no report demonstrating the role of the MePD histaminergic activity on the cardiovascular function in awake rats. The aims of the present work were: 1) to study the effects of two doses (10-100 nM) of HA microinjected in the MePD on basal cardiovascular recordings and on baroreflex- and chemoreflex-mediated responses; 2) to reveal whether cardiovascular reflex responses could be affected by MePD microinjections of (R)-alpha-methylhistamine (AH3), an agonist of the inhibitory autoreceptor H3; and, 3) to carry out a power spectral analysis to evaluate the contribution of the sympathetic and parasympathetic components in the variability of the HR and BP recordings. When compared with the control group (microinjected with saline, 0.3 microl), HA (10 nM) promoted an increase in the MAP50, i.e. the mean value of BP at half of the HR range evoked by the baroreflex response. Histamine (100 nM) did not affect the baroreflex activity, but significantly decreased the parasympathetic component of the HR variability, increased the sympathetic/parasympathetic balance at basal conditions (these two latter evaluated by the power spectral analysis), and promoted an impairment in the chemoreflex bradycardic response. Microinjection of AH3 (10 microM) led to mixed results, which resembled the effects of both doses of HA employed here. Present data suggest that cardiovascular changes induced by baroreceptors and chemoreceptors involve the histaminergic activity in the MePD. This neural regulation of reflex cardiovascular responses can have important implications for homeostatic and allostatic conditions and possibly for the

  6. Is the risk of cardiovascular disease altered with anti-inflammatory therapies? Insights from rheumatoid arthritis

    PubMed Central

    Kraakman, Michael J; Dragoljevic, Dragana; Kammoun, Helene L; Murphy, Andrew J

    2016-01-01

    Cardiovascular disease (CVD) remains the leading cause of mortality worldwide. Atherosclerosis is the most common form of CVD, which is complex and multifactorial with an elevated risk observed in people with either metabolic or inflammatory diseases. Accumulating evidence now links obesity with a state of chronic low-grade inflammation and has renewed our understanding of this condition and its associated comorbidities. An emerging theme linking disease states with atherosclerosis is the increased production of myeloid cells, which can initiate and exacerbate atherogenesis. Although anti-inflammatory drug treatments exist and have been successfully used to treat inflammatory conditions such as rheumatoid arthritis (RA), a commonly observed side effect is dyslipidemia, inadvertently, a major risk factor for the development of atherosclerosis. The mechanisms leading to dyslipidemia associated with anti-inflammatory drug use and whether CVD risk is actually increased by this dyslipidemia are of great therapeutic importance and currently remain poorly understood. Here we review recent data providing links between inflammation, hematopoiesis, dyslipidemia and CVD risk in the context of anti-inflammatory drug use. PMID:27350883

  7. Human cardiovascular and metabolic response to acute, severe isovolemic anemia.

    PubMed

    Weiskopf, R B; Viele, M K; Feiner, J; Kelley, S; Lieberman, J; Noorani, M; Leung, J M; Fisher, D M; Murray, W R; Toy, P; Moore, M A

    1998-01-21

    Although concern over the risks of red blood cell transfusion has resulted in several practice guidelines for transfusion, lack of data regarding the physiological effects of anemia in humans has caused uncertainty regarding the blood hemoglobin (Hb) concentration requiring treatment. To test the hypothesis that acute isovolemic reduction of blood Hb concentration to 50 g/L in healthy resting humans would produce inadequate cardiovascular compensation and result in tissue hypoxia secondary to inadequate oxygen transport. Before and after interventional study. Academic tertiary care medical center. Conscious healthy patients (n =11) prior to anesthesia and surgery and volunteers not undergoing surgery (n=21). Aliquots of blood (450-900 mL) were removed to reduce blood Hb concentration from 131 (2) g/L to 50 (1) g/L [mean (SE)]. Isovolemia was maintained with 5% human albumin and/or autologous plasma. Cardiovascular parameters, arterial and mixed venous oxygen content, oxyhemoglobin saturation, and arterial blood lactate were measured before and after removal of each aliquot of blood. Electrocardiogram and, in a subset, Holter monitor were monitored continuously. "Critical" oxygen delivery (TO2) as assessed by oxygen consumption (VO2), plasma lactate concentration, and ST changes on electrocardiogram. Acute, isovolemic reduction of Hb concentration decreased systemic vascular resistance and TO2 and increased heart rate, stroke volume, and cardiac index (each P<.001). We did not find evidence of inadequate oxygenation: VO2 increased slightly from a mean (SD) of 3.07 (0.44) mL of oxygen per kilogram per minute (mL O2 x kg(-1) x min[-1]) to 3.42 (0.54) mL O2 x kg(-1) x min(-1) (P<.001) and plasma lactate concentration did not change (0.81 [0.11] mmol/L to 0.62 [0.19] mmol/L; P=.09). Two subjects developed significant ST changes on Holter monitor: one apparently related to body position or activity, the other to an increase in heart rate (at an Hb concentration of 46

  8. Cardiovascular Response to Mental Stress Tests and the Prediction of Blood Pressure.

    PubMed

    Yuenyongchaiwat, Kornanong

    2017-01-01

    It has been proposed that increased physiological responses (i.e., cardiovascular reactivity) to a stressor or stressors may increase the risk of developing cardiovascular disease (CVD) including increased blood pressure (BP) or hypertension. However, many prospective studies have examined the hemodynamic reactions to laboratory stress tests and CVD in Western countries and only a few studies have examined with varying durations of follow-up in the same sample studies. In addition, still relatively little is known about cardiovascular reactivity in Asian populations. Therefore, the aim of this study was to examine whether cardiovascular responses to psychological stressors remained a significant predictor of 40-month follow-up among initially normotensive participants in Thailand, Asia. Hemodynamic parameter was measured at rest, during, and after mental arithmetic, a speech task, and a cold pressor task. Ninety-five healthy normotensive male and female participants were reevaluated BP at 40 months later. Regression analyses indicated that after adjustment for baseline BP, initial age, sex, body mass index, and family history of CVD, heightened systolic BP (SBP) responses to mental arithmetic was associated with increased future SBP (ΔR(2) = 0.04, P = 0.023). Therefore, these findings suggest that cardiovascular reactivity remains a prediction of future BP and may play a role in the development of hypertension and CVD.

  9. Cardiovascular responses to stress in Singapore and India.

    PubMed

    Kaur, Divjyot; Bishop, George D

    2013-02-01

    Epidemiological studies have shown significant ethnic differences in coronary heart disease death rates with South Asians showing significantly greater coronary heart disease mortality than other groups. This research examined ethnic differences in cardiovascular reactivity (CVR) among Chinese, Malays and Indians in Singapore as well as a sample of Indians living in India. Experiment 1 examined differences across 303 Chinese, Malay and Indian undergraduates in Singapore, while Experiment 2 looked at differences in CVR between Indian participants from Singapore, and 145 Indians living in India. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), cardiac index (CI) and total peripheral resistance index (TPRI) were measured during baselines and five laboratory tasks. Ethnicity main effects for SBP and CI reactivity were obtained in Experiment 1, with Indians showing significantly lower BP and CI reactivity than the Chinese and Malays. Significant main effects for sex were found with females showing lower reactivity than males for TPRI, and greater reactivity than males for HR and CI. Experiment 2 found that participants from India showed higher reactivity for SBP, HR and CI, while Indian participants from Singapore showed higher TPRI reactivity. These differences, however, often varied by task. These results point to differences in CVR among ethnic groups in Singapore as well as between Indians living in India and those living in Singapore. These differences may reflect cultural differences and need to be explored further with respect to their relationship to different rates of coronary heart disease among these groups. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Does chronic pain alter the normal interaction between cardiovascular and pain regulatory systems? Pain modulation in the hypertensive-monoarthritic rat.

    PubMed

    Pinho, Dora; Morato, Manuela; Couto, Marta R; Marques-Lopes, José; Tavares, Isaura; Albino-Teixeira, António

    2011-02-01

    Hypertension-associated hypoalgesia is widely recognized in acute pain conditions. In chronic pain states, however, the relationship between blood pressure and pain sensitivity is still ill-defined, with different authors reporting negative, positive, or even no relationship at all. This work addresses this issue, using complete Freund's adjuvant (CFA)-induced monoarthritis in different models of hypertension: Spontaneous (spontaneously hypertensive rats, SHR), induced by infusion of angiotensin II (ANG) or 1,3-dipropyl-8-sulfophenylxanthine (DPSPX, an adenosine receptors' antagonist), and renal artery ligation (RAL). Nociceptive responses associated with monoarthritis were evaluated by different behavioral tests (von Frey, ankle-bend and CatWalk) and by quantification of Fos expression at the dorsal horn upon noxious stimulation. In all hypertension models, higher von Frey thresholds and lower Fos expression were detected in hypertensive rats with chronic inflammatory pain, as compared to normotensive monoarthritic rats. In SHR and DPSPX, but not ANG or RAL models, hypertensive animals displayed lower inflammation than normotensives. Ankle-bend and CatWalk results indicated lower pain sensitivity in hypertensive rats only in SHR and DPSPX models. The present study shows the importance of using multiple models of hypertension, and evaluating pain responses by various methods, to better understand the complexity of the interactions between pain and cardiovascular regulatory systems. This study used different models of hypertension to investigate whether chronic pain alters the normal integration of cardiovascular and pain regulatory systems. A complete understanding of the mechanisms underlying the complex interactions between these systems may disclose future therapeutic approaches to treat hypertension/chronic pain comorbidity states. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  11. Cardiovascular and organ responses and adaptation responses to hypogravity in an experimental animal model.

    NASA Astrophysics Data System (ADS)

    Biondi, R.; Capodicasa, E.; Tassi, C.; Mezzasomal, L.; Benedetti, C.; Valiani, M.; Marconi, P.; Rossi, R.

    1995-10-01

    The head-down suspension (i.e antiorthostatic hypokinesia) rat is used to simulate weightlessness. However, little is known about cardiovascular and organ adaptation responses which, over a long time, can become pathologically significant. The purpose of this study was therefore to evaluate regional changes in the hematology parameters, Endotheline-1 (ET-1) concentration and urinary excretion of N-acetyl-β-D-glucosaminidase (EC 3.2.1.30) (NAG) in an experimental antiorthostatic rat model. The data indicate significant variations in the plasma ET-1 level in time, in the superior and inferior cava vessel blood of animals maintained for 10 days in hypogravity with respect to controls. These changes do not seem to be due to hemoconcentration. The increase in urinary NAG was observed during the first 24h of experiment, indicating renal stress, probably due to adverse blood flow variations within the organ. We conclude that the plasma ET-1 level changes could be responsible, overall for the blood flow variations in the kidney and renal stress could be the consequence of extended antiorthostatic hypokinesia. The ET-1 behaviour and urinary NAG excretion in rats exposed to antiorthostatic hypokjnetic hydynamia offer possibilities for understanding if these changes might be reversible or when they become pathological. This could give some relevant information about the effects of prolonged hypogravity during the space voyage.

  12. Cardiovascular and organ responses and adaptation responses to hypogravity in an experimental animal model.

    PubMed

    Biondi, R; Capodicasa, E; Tassi, C; Mezzasoma, L; Benedetti, C; Valiani, M; Marconi, P; Rossi, R

    1995-10-01

    The head-down suspension (i.e. antiorthostatic hypokinesia) rat is used to simulate weightlessness. However, little is known about cardiovascular and organ adaptation responses which, over a long time, can become pathologically significant. The purpose of this study was therefore to evaluate regional changes in the hematology parameters. Endotheline-1 (ET-1) concentration and urinary excretion of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) (NAG) in an experimental antiorthostatic rat model. The data indicate significant variations in the plasma ET-1 level in time, in the superior and inferior cava vessel blood of animals maintained for 10 days in hypogravity with respect to controls. These changes do not seem to be due to hemoconcentration. The increase in urinary NAG was observed during the first 24h of experiment, indicating renal stress, probably due to adverse blood flow variations within the organ. We conclude that the plasma ET-1 level changes could be responsible, overall for the blood flow variations in the kidney and renal stress could be the consequence of extended antiorthostatic hypokinesia. The ET-1 behaviour and urinary NAG excretion in rats exposed to antiorthostatic hypokinetic hydynamia offer possibilities for understanding if these changes might be reversible or when they become pathological. This could give some relevant information about the effects of prolonged hypogravity during the space voyage.

  13. How linear features alter predator movement and the functional response

    PubMed Central

    McKenzie, Hannah W.; Merrill, Evelyn H.; Spiteri, Raymond J.; Lewis, Mark A.

    2012-01-01

    In areas of oil and gas exploration, seismic lines have been reported to alter the movement patterns of wolves (Canis lupus). We developed a mechanistic first passage time model, based on an anisotropic elliptic partial differential equation, and used this to explore how wolf movement responses to seismic lines influence the encounter rate of the wolves with their prey. The model was parametrized using 5 min GPS location data. These data showed that wolves travelled faster on seismic lines and had a higher probability of staying on a seismic line once they were on it. We simulated wolf movement on a range of seismic line densities and drew implications for the rate of predator–prey interactions as described by the functional response. The functional response exhibited a more than linear increase with respect to prey density (type III) as well as interactions with seismic line density. Encounter rates were significantly higher in landscapes with high seismic line density and were most pronounced at low prey densities. This suggests that prey at low population densities are at higher risk in environments with a high seismic line density unless they learn to avoid them. PMID:22419990

  14. Growth-altering microbial interactions are responsive to chemical context.

    PubMed

    Liu, Angela; Archer, Anne M; Biggs, Matthew B; Papin, Jason A

    2017-01-01

    Microbial interactions are ubiquitous in nature, and are equally as relevant to human wellbeing as the identities of the interacting microbes. However, microbial interactions are difficult to measure and characterize. Furthermore, there is growing evidence that they are not fixed, but dependent on environmental context. We present a novel workflow for inferring microbial interactions that integrates semi-automated image analysis with a colony stamping mechanism, with the overall effect of improving throughput and reproducibility of colony interaction assays. We apply our approach to infer interactions among bacterial species associated with the normal lung microbiome, and how those interactions are altered by the presence of benzo[a]pyrene, a carcinogenic compound found in cigarettes. We found that the presence of this single compound changed the interaction network, demonstrating that microbial interactions are indeed dynamic and responsive to local chemical context.

  15. Compassion training alters altruism and neural responses to suffering.

    PubMed

    Weng, Helen Y; Fox, Andrew S; Shackman, Alexander J; Stodola, Diane E; Caldwell, Jessica Z K; Olson, Matthew C; Rogers, Gregory M; Davidson, Richard J

    2013-07-01

    Compassion is a key motivator of altruistic behavior, but little is known about individuals' capacity to cultivate compassion through training. We examined whether compassion may be systematically trained by testing whether (a) short-term compassion training increases altruistic behavior and (b) individual differences in altruism are associated with training-induced changes in neural responses to suffering. In healthy adults, we found that compassion training increased altruistic redistribution of funds to a victim encountered outside of the training context. Furthermore, increased altruistic behavior after compassion training was associated with altered activation in brain regions implicated in social cognition and emotion regulation, including the inferior parietal cortex and dorsolateral prefrontal cortex (DLPFC), and in DLPFC connectivity with the nucleus accumbens. These results suggest that compassion can be cultivated with training and that greater altruistic behavior may emerge from increased engagement of neural systems implicated in understanding the suffering of other people, executive and emotional control, and reward processing.

  16. Growth-altering microbial interactions are responsive to chemical context

    PubMed Central

    2017-01-01

    Microbial interactions are ubiquitous in nature, and are equally as relevant to human wellbeing as the identities of the interacting microbes. However, microbial interactions are difficult to measure and characterize. Furthermore, there is growing evidence that they are not fixed, but dependent on environmental context. We present a novel workflow for inferring microbial interactions that integrates semi-automated image analysis with a colony stamping mechanism, with the overall effect of improving throughput and reproducibility of colony interaction assays. We apply our approach to infer interactions among bacterial species associated with the normal lung microbiome, and how those interactions are altered by the presence of benzo[a]pyrene, a carcinogenic compound found in cigarettes. We found that the presence of this single compound changed the interaction network, demonstrating that microbial interactions are indeed dynamic and responsive to local chemical context. PMID:28319121

  17. Streamflow response to increasing precipitation extremes altered by forest management

    NASA Astrophysics Data System (ADS)

    Kelly, Charlene N.; McGuire, Kevin J.; Miniat, Chelcy Ford; Vose, James M.

    2016-04-01

    Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in streamflow that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current streamflow models by quantifying the impact of the interaction between forest management and precipitation. We use daily long-term data from paired watersheds that have undergone forest harvest or species conversion. We find that interactive effects of climate change, represented by changes in observed precipitation trends, and forest management regime, significantly alter expected streamflow most often during extreme events, ranging from a decrease of 59% to an increase of 40% in streamflow, depending upon management. Our results suggest that vegetation might be managed to compensate for hydrologic responses due to climate change to help mitigate effects of extreme changes in precipitation.

  18. Cardiovascular responses during orthostasis - Effect of an increase in maximal O2 uptake

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.; Montgomery, L. D.; Greenleaf, J. E.

    1984-01-01

    A study is described which tests the hypothesis that changes in aerobic activity (increases in maximum oxygen uptake) will reduce the effectiveness of cardiovascular reflexes to regulate blood pressure during orthostasis. The hypothesis was tested by measuring heart rate, blood pressure and blood volume responses in eight healthy male subjects before and after an eight-day endurance regimen. The results of the study suggest that the physiologic responses to orthostasis are dependent upon the rate of plasma volume loss and pooling, and are associated with training-induced hypervolemia. It is indicated that endurance type exercise training enhances cardiovascular adjustments during tilt. The implications of these results for the use of exercise training as a countermeasure and/or therapeutic method for the prevention of cardiovascular instability during orthostatic stress are discussed.

  19. Cardiovascular responses during orthostasis - Effect of an increase in maximal O2 uptake

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.; Montgomery, L. D.; Greenleaf, J. E.

    1984-01-01

    A study is described which tests the hypothesis that changes in aerobic activity (increases in maximum oxygen uptake) will reduce the effectiveness of cardiovascular reflexes to regulate blood pressure during orthostasis. The hypothesis was tested by measuring heart rate, blood pressure and blood volume responses in eight healthy male subjects before and after an eight-day endurance regimen. The results of the study suggest that the physiologic responses to orthostasis are dependent upon the rate of plasma volume loss and pooling, and are associated with training-induced hypervolemia. It is indicated that endurance type exercise training enhances cardiovascular adjustments during tilt. The implications of these results for the use of exercise training as a countermeasure and/or therapeutic method for the prevention of cardiovascular instability during orthostatic stress are discussed.

  20. Cardiovascular and emotional responses in women: the role of hostility and harassment.

    PubMed

    Suarez, E C; Harlan, E; Peoples, M C; Williams, R B

    1993-11-01

    The relation of hostility and harassment to cardiovascular and emotional responses was examined by having 51 women (ages 18-26) high and low in hostility complete a task with or without harassment. Harassed high hostile Ss showed greater systolic blood pressure (SBP) increases during task and recovery periods than did harassed low hostile Ss and nonharassed Ss. Harassed low hostile Ss evidenced greater SBP increases during task and recovery periods than did nonharassed Ss. Among high hostile women, cardiovascular elevations during the task were associated with self-reported levels of negative affect. Antagonistic hostility, relative to neurotic hostility, was positively associated with harassment-induced SBP changes. These results support the hypothesis that hostile people exhibit excessive behaviorally induced cardiovascular responses to interpersonally challenging tasks that evoke anger-related emotional states.

  1. Cardiovascular autonomic responsiveness in postmenopausal women with and without hot flushes.

    PubMed

    Hautamäki, Hanna; Piirilä, Päivi; Haapalahti, Petri; Tuomikoski, Pauliina; Sovijärvi, Anssi R A; Ylikorkala, Olavi; Mikkola, Tomi S

    2011-04-01

    During menopausal transition autonomic balance is known to shift towards sympathetic dominance, but the role of vasomotor hot flushes in this phenomenon is not understood. We compared cardiovascular autonomic responsiveness between women with and without hot flushes. One hundred fifty recently postmenopausal healthy women with varying degree of hot flushes (none, mild, moderate, severe) underwent comprehensive cardiovascular autonomic nervous testing (controlled and deep breathing, active orthostatic test, Valsalva manoeuvre and handgrip test) assessing both sympathetic and parasympathetic activity. The responses of heart rate, heart rate variability and blood pressure in these tests were evaluated. Responses in heart rate showed differences between the study groups only in the Valsalva manoeuvre where the tachycardia ratio in all symptomatic women was lower (p=0.041) than in women without hot flushes. Neither change in the heart rate variability analyses nor the blood pressure responses were affected by hot flush status. However, there was a non-significantly higher maximum systolic (140 (112-182)mmHg vs. 135 (102-208)mmHg) and diastolic blood pressure (94 (72-112)mmHg vs. 90 (66-122)mmHg) following the handgrip test in women without hot flushes vs. all the symptomatic women. Menopausal hot flushes seem to be associated with a possibly increased sympathetic preponderance without an effect on parasympathetic activity in cardiovascular autonomic responses. This may imply a potentially negative impact on cardiovascular health in women experiencing hot flushes. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. HDL-S1P: cardiovascular functions, disease-associated alterations, and therapeutic applications

    PubMed Central

    Levkau, Bodo

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid contained in High-density lipoproteins (HDL) and has drawn considerable attention in the lipoprotein field as numerous studies have demonstrated its contribution to several functions inherent to HDL. Some of them are partly and some entirely due to the S1P contained in HDL (HDL-S1P). Despite the presence of over 1000 different lipids in HDL, S1P stands out as it possesses its own cell surface receptors through which it exercises key physiological functions. Most of the S1P in human plasma is associated with HDL, and the amount of HDL-S1P influences the quality and quantity of HDL-dependent functions. The main binding partner of S1P in HDL is apolipoprotein M but others may also exist particularly under conditions of acute S1P elevations. HDL not only exercise functions through their S1P content but have also an impact on genuine S1P signaling by influencing S1P bioactivity and receptor presentation. HDL-S1P content is altered in human diseases such as atherosclerosis, coronary artery disease, myocardial infarction, renal insufficiency and diabetes mellitus. Low HDL-S1P has also been linked to impaired HDL functions associated with these disorders. Although the pathophysiological and molecular reasons for such disease-associated shifts in HDL-S1P are little understood, there have been successful approaches to circumvent their adverse implications by pharmacologically increasing HDL-S1P as means to improve HDL function. This mini-review will cover the current understanding of the contribution of HDL-S1P to physiological HDL function, its alteration in disease and ways for its restoration to correct HDL dysfunction. PMID:26539121

  3. HDL-S1P: cardiovascular functions, disease-associated alterations, and therapeutic applications.

    PubMed

    Levkau, Bodo

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid contained in High-density lipoproteins (HDL) and has drawn considerable attention in the lipoprotein field as numerous studies have demonstrated its contribution to several functions inherent to HDL. Some of them are partly and some entirely due to the S1P contained in HDL (HDL-S1P). Despite the presence of over 1000 different lipids in HDL, S1P stands out as it possesses its own cell surface receptors through which it exercises key physiological functions. Most of the S1P in human plasma is associated with HDL, and the amount of HDL-S1P influences the quality and quantity of HDL-dependent functions. The main binding partner of S1P in HDL is apolipoprotein M but others may also exist particularly under conditions of acute S1P elevations. HDL not only exercise functions through their S1P content but have also an impact on genuine S1P signaling by influencing S1P bioactivity and receptor presentation. HDL-S1P content is altered in human diseases such as atherosclerosis, coronary artery disease, myocardial infarction, renal insufficiency and diabetes mellitus. Low HDL-S1P has also been linked to impaired HDL functions associated with these disorders. Although the pathophysiological and molecular reasons for such disease-associated shifts in HDL-S1P are little understood, there have been successful approaches to circumvent their adverse implications by pharmacologically increasing HDL-S1P as means to improve HDL function. This mini-review will cover the current understanding of the contribution of HDL-S1P to physiological HDL function, its alteration in disease and ways for its restoration to correct HDL dysfunction.

  4. Cardiovascular response during urodynamics in individuals with spinal cord injury.

    PubMed

    Liu, N; Zhou, M-W; Biering-Sørensen, F; Krassioukov, A V

    2017-03-01

    Retrospective chart review. To establish the frequency and severity of autonomic dysreflexia (AD) during urodynamics among individuals with chronic spinal cord injury (SCI) and to investigate the possible effect of the number of years since SCI on the severity of AD. SCI outpatient clinic. A retrospective chart review was undertaken of individuals with SCI who were seen at an outpatient clinic and could potentially develop an episode of AD (T6 and above). Data regarding age, gender, urodynamic examination, lower urinary tract function, cardiovascular parameters and SCI were collected. In addition, information on signs and symptoms of AD were retrieved. A total of 76 individuals with SCI were examined with blood pressure (BP) monitoring. The majority had cervical SCI (79%). The mean age was 47.8±13.9 years. The median duration after SCI was 51.5 months. During urodynamics, a total of 48 (63.2%) individuals showed an increase in systolic BP>20 mm Hg, meeting the criteria for AD. Indicators for higher incidences of AD were cervical SCI, being >2 years after SCI, the presence of detrusor sphincter dyssynergia (DSD) and low bladder compliance. AD was more severe in individuals with complete (American Spinal Cord Association (ASIA) impairment scale (AIS) A) injuries, worse with greater time after SCI. Individuals with cervical SCI, DSD, poor bladder compliance or >2 years after SCI were associated with a higher possibility of developing AD during urodynamics. Furthermore, AD was more severe in complete (AIS A) individuals and was exacerbated with time after injury.

  5. Frontal brain asymmetry and transient cardiovascular responses to the perception of humor.

    PubMed

    Papousek, Ilona; Schulter, Günter; Weiss, Elisabeth M; Samson, Andrea C; Freudenthaler, H Harald; Lackner, Helmut K

    2013-04-01

    The study examined the relationship of individual differences in prefrontal brain asymmetry, measured by the EEG in resting conditions, to the individual's responsivity in the context of humor (n=42). Several weeks after the EEG recording, immediate cardiovascular responses to the perception of humor and behavioral indicators of humor processing were obtained in an experimental paradigm involving non-verbal cartoons. Relatively greater resting activity in the left than right prefrontal cortex, particularly at the ventrolateral positions, was associated with faster detection of humor, a more pronounced cardiac response to the perception of humor (heart rate and cardiac output), and more accessible internal positive affective states (indicated by faster reports of amusement levels). The study confirms and extends findings of the relevance of prefrontal brain asymmetry to affective responsivity, contributing evidence in the domain of positive affect and humor, and demonstrating relationships to the immediate cardiovascular response pattern to an emotional event.

  6. Endothelial Inflammatory Transcriptional Responses to an Altered Plasma Exposome Following Inhalation of Diesel Emissions

    EPA Science Inventory

    BACKGROUND:Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive extrapulmonary pathology.OBJECTIVES:Previously, we found that canonical inflammatory response tra...

  7. Endothelial Inflammatory Transcriptional Responses to an Altered Plasma Exposome Following Inhalation of Diesel Emissions

    EPA Science Inventory

    BACKGROUND:Air pollution, especially emissions derived from traffic sources, is associated with adverse cardiovascular outcomes. However, it remains unclear how inhaled factors drive extrapulmonary pathology.OBJECTIVES:Previously, we found that canonical inflammatory response tra...

  8. Cardiovascular imaging with computed tomography: responsible steps to balancing diagnostic yield and radiation exposure.

    PubMed

    Halliburton, Sandra S; Schoenhagen, Paul

    2010-05-01

    Cardiovascular computed tomography (CT) is at the center of the risk-benefit debate about ionizing radiation exposure to the public from medical procedures. Although the risk has been sensationalized, the cardiovascular CT community has responded to the scrutiny by increasing efforts to ensure the responsible use of this young technology. Efforts to date have primarily included the development of appropriateness criteria and the implementation of dose-lowering techniques. Still needed is the development of standards that incorporate radiation exposure optimization into scan protocol selection. Such standards must consider applied radiation in the context of the clinical indication as well as the characteristics of the patient and provide guidance with regard to specific parameter settings. This editorial viewpoint demonstrates the need for comprehensive, individualized review of the clinical scenario before performing a cardiovascular CT, as well as the need for standards. If cardiovascular CT is the appropriate test and scan parameters are optimized with respect to radiation exposure, benefit should necessarily outweigh potential risk. However, efforts to promote responsible cardiovascular CT imaging must continue to ensure this is true for every patient.

  9. Reduced cardiovascular responsiveness to exercise-induced sympathoadrenergic stimulation in patients with cirrhosis.

    PubMed

    Bernardi, M; Rubboli, A; Trevisani, F; Cancellieri, C; Ligabue, A; Baraldini, M; Gasbarrini, G

    1991-03-01

    Cardiovascular responsiveness to sympathoadrenergic activation obtained by muscle exercise in the supine position was evaluated in 22 patients with cirrhosis (11 alcoholic, 11 postnecrotic/cryptogenic; 14 with ascites) and 10 controls of comparable age. Plasma norepinephrine, heart rate, diastolic arterial pressure and cardiac function, as evaluated by systolic time intervals, were monitored. At rest, cirrhotics had higher norepinephrine (154 +/- 19 S.E.M. ng/l) and heart rate (79 +/- 2 beats per min) than controls (71 +/- 3 ng/l, p less than 0.01; 67 +/- 2 beats per min, p less than 0.001), whereas diastolic arterial pressure was similar. Among systolic time intervals, electromechanical systole, pre-ejection period, electromechanical delay and pre-ejection period to left ventricular ejection time ratios were prolonged (p less than 0.05 or less). Exercise led to significant increases in plasma norepinephrine, heart rate and diastolic arterial pressure in both controls and patients. In the latter, however, whereas the increase in norepinephrine was greater (p less than 0.001), those in heart rate and diastolic arterial pressure were less (p less than 0.005). As expected, most systolic time intervals shortened, but the decrease in pre-ejection period (p less than 0.05), isometric contraction time (p less than 0.02) and pre-ejection period to left ventricular ejection time ratio (p = 0.06) was less in patients than in controls. Direct correlations between exercise-induced changes in norepinephrine and both diastolic arterial pressure (r = 0.81; p less than 0.005) and heart rate (r = 0.85; p less than 0.002) were observed in controls, while inverse correlations (r = -0.67, p less than 0.001 and r = -0.44; p less than 0.05) were found in cirrhotics. These results suggest that cardiovascular reactivity to the sympathetic drive is impaired in cirrhotics. The impairment of cardiac contractility may be due to altered electromechanical coupling.

  10. Concord grape juice polyphenols and cardiovascular risk factors: dose-response relationships

    USDA-ARS?s Scientific Manuscript database

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship ...

  11. Appraisal, Coping, Task Performance, and Cardiovascular Responses during the Evaluated Speaking Task.

    ERIC Educational Resources Information Center

    Baggett, H. Lane; And Others

    1996-01-01

    Appraisal, coping, task performance, and cardiovascular responses were examined among men high and low in speech anxiety who prepared and performed a speech under evaluative conditions. Speech-anxious men saw the task as more threatening. They were more stressed, anxious, distracted, and aware of their emotions, focused on the passage of time, and…

  12. Cardiovascular responses to l-glutamate microinjection into the NTS are abrogated by reduced glutathione.

    PubMed

    Granato, Álisson Silva; Gomes, Paula Magalhães; Martins Sá, Renato William; Borges, Gabriel Silva Marques; Alzamora, Andréia Carvalho; de Oliveira, Lisandra Brandino; Toney, Glenn M; Cardoso, Leonardo M

    2017-03-06

    Redox imbalance in regions of the CNS controlling blood pressure is increasingly recognized as a leading factor for hypertension. Nucleus tractus solitarius (NTS) of the dorsomedial medulla is the main region receiving excitatory visceral sensory inputs that modulate autonomic efferent drive to the cardiovascular system. This study sought to determine the capacity of reduced glutathione, a major bioactive antioxidant, to modulate NTS-mediated control of cardiovascular function in unanaesthetized rats. Male Fischer 344 rats were used for microinjection experiments. Cardiovascular responses to l-glutamate were first used to verify accurate placement of injections into the dorsomedial region comprising the NTS. Next, responses to GSH or vehicle were recorded followed by responses to l-glutamate again at the same site. GSH microinjection increased mean arterial pressure (MAP) compared to vehicle and abrogated responses to subsequent injection of l-glutamate. These data indicate that GSH microinjection into the NTS affects blood pressure regulation by dorsomedial neuronal circuits and blunts l-glutamate driven excitation in this region. These findings raise the possibility that increased antioxidant actions of GSH in NTS could contribute to autonomic control dysfunctions of the cardiovascular system.

  13. Mutants of PC12 cells with altered cyclic AMP responses

    SciTech Connect

    Block, T.; Kon, C.; Breckenridge, B.M.

    1984-10-01

    PCl2 cells, derived from a rat pheochromocytoma, were mutagenized and selected in media containing agents known to elevate intracellular concentrations of cyclic AMP (cAMP). More than 40 clones were isolated by selection with cholera toxin or 2-chloroadenosine or both. The variants that were deficient in accumulating cAMP were obtained by using a protocol in which 1 ..mu..m 8-bromo-cAMP was included in addition to the agonist. Certain of these variants were partially characterized with respect to the site of altered cAMP metabolism. The profiles of adenylate cyclase activity responsiveness of certain variants to guanosine-5'-(BETA,..gamma..-imido) triphosphate and to forskolin resembled those of UNC and cyc phenotypes of S49 lymphoma cells, which are functionally deficient in the GTP-sensitive coupling protein, N/sub s/. Other variants were characterized by increased cyclic nucleotide phosphodiesterase activity at low substrate concentration. Diverse morphological traits were observed among the variants, but it was not possible to assign them to a particular cAMP phenotype. Two revertants of a PCl2 mutant were isolated and observed to have regained a cellular cAMP response to 2-chloroadenosine and to forskolin. It is hoped that these PCl2 mutants will have utility for defining cAMP-mediated functions, including any links to the action of nerve growth factor, in cells derived from the neural crest.

  14. Altered brain response for semantic knowledge in Alzheimer's disease.

    PubMed

    Wierenga, Christina E; Stricker, Nikki H; McCauley, Ashley; Simmons, Alan; Jak, Amy J; Chang, Yu-Ling; Nation, Daniel A; Bangen, Katherine J; Salmon, David P; Bondi, Mark W

    2011-02-01

    Word retrieval deficits are common in Alzheimer's disease (AD) and are thought to reflect a degradation of semantic memory. Yet, the nature of semantic deterioration in AD and the underlying neural correlates of these semantic memory changes remain largely unknown. We examined the semantic memory impairment in AD by investigating the neural correlates of category knowledge (e.g., living vs. nonliving) and featural processing (global vs. local visual information). During event-related fMRI, 10 adults diagnosed with mild AD and 22 cognitively normal (CN) older adults named aloud items from three categories for which processing of specific visual features has previously been dissociated from categorical features. Results showed widespread group differences in the categorical representation of semantic knowledge in several language-related brain areas. For example, the right inferior frontal gyrus showed selective brain response for nonliving items in the CN group but living items in the AD group. Additionally, the AD group showed increased brain response for word retrieval irrespective of category in Broca's homologue in the right hemisphere and rostral cingulate cortex bilaterally, which suggests greater recruitment of frontally mediated neural compensatory mechanisms in the face of semantic alteration. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Effects of 10-ppm hydrogen sulfide inhalation in exercising men and women. Cardiovascular, metabolic, and biochemical responses.

    PubMed

    Bhambhani, Y; Burnham, R; Snydmiller, G; MacLean, I

    1997-02-01

    This study examined the acute effects of 10-ppm hydrogen sulfide (H2S) inhalation, a concentration equal to its occupational exposure limit, on the cardiovascular, metabolic, and biochemical responses in healthy volunteers. Fifteen men and 13 women completed two 30-minute exercise sessions at 50% of their maximal oxygen uptake, during which they inhaled medical air or 10 ppm H2S in a blind manner. Arterial and finger-prick blood samples were obtained before and during the final minute of exercise. Muscle biopsies were withdrawn from the right vastus lateralis immediately after exercise. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram and blood pressure apparatus. A significant decrease in oxygen uptake (VO2), with a concomitant increase in blood lactate, was observed in men and women as a result of H2S exposure. No significant changes were observed in arterial blood parameters and the cardiovascular responses under these conditions. Muscle lactate, as well as the activities of lactate dehydrogenase, citrate synthase, and cytochrome oxidase, were not significantly altered by H2S exposure. However, there was a tendency for muscle lactate to increase and citrate synthase activity to decrease in both genders in the presence of H2S. It appeared that 10-ppm H2S inhalation reduced VO2 during exercise, most likely by inhibiting the aerobic capacity of the exercising muscle. These findings question the scientific validity of the current occupational exposure limit for H2S.

  16. Role of the autonomic nervous system and baroreflex in stress-evoked cardiovascular responses in rats.

    PubMed

    Dos Reis, Daniel Gustavo; Fortaleza, Eduardo Albino Trindade; Tavares, Rodrigo Fiacadori; Corrêa, Fernando Morgan Aguiar

    2014-07-01

    Restraint stress (RS) is an experimental model to study stress-related cardiovascular responses, characterized by sustained pressor and tachycardiac responses. We used pharmacologic and surgical procedures to investigate the role played by sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS) in the mediation of stress-evoked cardiovascular responses. Ganglionic blockade with pentolinium significantly reduced RS-evoked pressor and tachycardiac responses. Intravenous treatment with homatropine methyl bromide did not affect the pressor response but increased tachycardia. Pretreatment with prazosin reduced the pressor and increased the tachycardiac response. Pretreatment with atenolol did not affect the pressor response but reduced tachycardia. The combined treatment with atenolol and prazosin reduced both pressor and tachycardiac responses. Adrenal demedullation reduced the pressor response without affecting tachycardia. Sinoaortic denervation increased pressor and tachycardiac responses. The results indicate that: (1) the RS-evoked cardiovascular response is mediated by the autonomic nervous system without an important involvement of humoral factors; (2) hypertension results primarily from sympathovascular and sympathoadrenal activation, without a significant involvement of the cardiac sympathetic component (CSNS); (3) the abrupt initial peak in the hypertensive response to restraint is sympathovascular-mediated, whereas the less intense but sustained hypertensive response observed throughout the remaining restraint session is mainly mediated by sympathoadrenal activation and epinephrine release; (4) tachycardia results from CSNS activation, and not from PSNS inhibition; (5) RS evokes simultaneous CSNS and PSNS activation, and heart rate changes are a vector of both influences; (6) the baroreflex is functional during restraint, and modulates both the vascular and cardiac responses to restraint.

  17. Altered Functional Response to Risky Choice in HIV Infection

    PubMed Central

    Connolly, Colm G.; Bischoff-Grethe, Amanda; Jordan, Stephan J.; Woods, Steven Paul; Ellis, Ronald J.; Paulus, Martin P.; Grant, Igor

    2014-01-01

    Background Risky decision-making is commonly observed in persons at risk for and infected with HIV and is associated with executive dysfunction. Yet it is currently unknown whether HIV alters brain processing of risk-taking decision-making. Methods This study examined the neural substrate of a risky decision-making task in 21 HIV seropositive (HIV+) and 19 seronegative (HIV-) comparison participants. Functional magnetic resonance imaging was conducted while participants performed the risky-gains task, which involves choosing among safe (20 cents) and risky (40/80 cent win or loss) choices. Linear mixed effects analyses examining group and decision type were conducted. Robust regressions were performed to examine the relationship between nadir CD4 count and Kalichman sexual compulsivity and brain activation in the HIV+ group. The overlap between the task effects and robust regressions was explored. Results Although there were no serostatus effects in behavioral performance on the risky-gains task, HIV+ individuals exhibited greater activation for risky choices in the basal ganglia, i.e. the caudate nucleus, but also in the anterior cingulate, dorsolateral prefrontal cortex, and insula relative to the HIV- group. The HIV+ group also demonstrated reduced functional responses to safe choices in the anterior cingulate and dorsolateral prefrontal cortex relative to the HIV- group. HIV+ individuals with higher nadir CD4 count and greater sexual compulsivity displayed lower differential responses to safe versus risky choices in many of these regions. Conclusions This study demonstrated fronto-striatal loop dysfunction associated with HIV infection during risky decision-making. Combined with similar between-group task behavior, this suggests an adaptive functional response in regions critical to reward and behavioral control in the HIV+ group. HIV-infected individuals with higher CD4 nadirs demonstrated activation patterns more similar to seronegative individuals. This

  18. Neonatal handling alters maternal emotional response to stress.

    PubMed

    Reis, Adolfo R; Jacobs, Silvana; Menegotto, Pâmela R; Silveira, Patrícia P; Lucion, Aldo B

    2016-07-01

    Neonatal handling is an experimental procedure used to analyze the effects of environmental interventions during early postpartum days (PPD). Long-lasting effects of repeated stress exposure in the neonatal period on the maternal side are poorly studied in this model. The aim of this study was to verify if handling the pups induces enduring effects on damśstress responses, increasing their risk for depression. Dams were divided into two groups (NH-Non-handled and H-Handled) based on the handling procedure (pups were handled for 1 min/per day from PPD1-PPD10) and then subdivided into four groups (NH, NH + S, H, and H + S) based on the exposure or not to restraint stress after weaning (1 hr/per day for 7 days, PPD22-PPD28). We analyzed damśbehavior in the forced swimming test (FST PPD29-PPD30), plasma basal corticosterone and BDNF levels, as well as adrenal weight (PPD31). The results show that handling alters the stress response of dams to acute and chronic stress, as evidenced by dams of the H group having increased immobility in the first day of FST (p < .001), similar to NH + S (p < .01). Dams of the H and H + S groups show decreased levels of corticosterone when compared to NH and NH + S groups (p < .05), but the H + S group shows an increased adrenal weight, suggesting an increased sensibility of the maternal organism to the chronic stress applied after weaning (p < .05). We show that handling may induce a long-lasting effect on maternal stress response; these changes in the damśemotional reactivity increase their susceptibility for the development of psychiatric disorders such as depression. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58: 614-622, 2016. © 2016 Wiley Periodicals, Inc.

  19. Response of the Cardiovascular System to Vibration and Combined Stresses

    DTIC Science & Technology

    1980-11-01

    an afferent ( sensory ) mechanism which adjusted venous return or b) an efferent mechanism responsible for adjustment of diastolic (relaxed) heart size...the end of the test period. In addition, it appeared to be independent of both cardiac innervation, particularly righL heart afferent infor-mation and...the end of the test period. In addition, it appeared to be independent of both cardiac innervation, particularly right heart afferent information, and

  20. Cardiovascular responses to head-up tilt after an endurance exercise program.

    PubMed

    Pawelczyk, J A; Kenney, W L; Kenney, P

    1988-02-01

    The cardiovascular responses to 10 min of orthostasis were assessed before and after an aerobic exercise program. Five men and five women (18-25 years old) exercised for 7 weeks, four times per week, for 50 min per session at 70% of maximal heart rate (HR). Before and after the exercise program, maximal aerobic power (VO2max) was determined, and HR, systolic (SBP), diastolic (DBP), and pulse (PP) blood pressures were measured each minute during 5 min of supine rest, 10 min of foot-supported 70 degree head-up tilt (HUT), and 5 min of supine rest. Orthostatic tolerance was not determined. Calf compliance was measured in five of the subjects before and after the program as the change in leg volume at occluding pressures of 20, 40, 60, 80, and 100 mm Hg. Following the program, VO2max increased by 8.7% (p = 0.012), while decreases were noted in resting HR (9.4%, p = 0.041), SBP (5.0%, p less than 0.0005), and DBP (14.2%, p less than 0.0005). Despite a greater HR increase during HUT (7.1 beat.min-1, p = 0.034), SBP decreased by 3.4 mm Hg during HUT after the exercise program (p = 0.008). No differences were noted in the changes in DBP, MAP, or PP upon tilting (p greater than 0.05). After the program, the amount of fluid pooled in the calf at high occluding pressures (80 and 100 mm Hg) increased by 0.96 +/- 0.24 and 1.10 +/- 0.33 ml.100 ml tissue-1 (X +/- S.E.M., p = 0.017 and p = 0.028, respectively). We suggest that control of blood pressure during 10 min of orthostasis may be altered by endurance exercise training.

  1. Altered glucose metabolism and hypoxic response in alloxan-induced diabetic atherosclerosis in rabbits.

    PubMed

    Matsuura, Yunosuke; Yamashita, Atsushi; Zhao, Yan; Iwakiri, Takashi; Yamasaki, Kazuaki; Sugita, Chihiro; Koshimoto, Chihiro; Kitamura, Kazuo; Kawai, Keiichi; Tamaki, Nagara; Zhao, Songji; Kuge, Yuji; Asada, Yujiro

    2017-01-01

    Diabetes mellitus accelerates atherosclerosis that causes most cardiovascular events. Several metabolic pathways are considered to contribute to the development of atherosclerosis, but comprehensive metabolic alterations to atherosclerotic arterial cells remain unknown. The present study investigated metabolic changes and their relationship to vascular histopathological changes in the atherosclerotic arteries of rabbits with alloxan-induced diabetes. Diabetic atherosclerosis was induced in rabbit ilio-femoral arteries by injecting alloxan (100 mg/kg), injuring the arteries using a balloon, and feeding with a 0.5% cholesterol diet. We histologically assessed the atherosclerotic lesion development, cellular content, pimonidazole positive-hypoxic area, the nuclear localization of hypoxia-inducible factor-1α, and apoptosis. We evaluated comprehensive arterial metabolism by performing metabolomic analyses using capillary electrophoresis-time of flight mass spectrometry. We evaluated glucose uptake and its relationship to vascular hypoxia using 18F-fluorodeoxyglucose and pimonidazole. Plaque burden, macrophage content, and hypoxic areas were more prevalent in arteries with diabetic, than non-diabetic atherosclerosis. Metabolomic analyses highlighted 12 metabolites that were significantly altered between diabetic and non-diabetic atherosclerosis. A half of them were associated with glycolysis metabolites, and their levels were decreased in diabetic atherosclerosis. The uptake of glucose evaluated as 18F-fluorodeoxyglucose in atherosclerotic lesions increased according to increased macrophage content or hypoxic areas in non-diabetic, but not diabetic rabbits. Despite profound hypoxic areas, the nuclear localization of hypoxia-inducible factor-1α decreased and the number of apoptotic cells increased in diabetic atherosclerotic lesions. Altered glycolysis metabolism and an impaired response to hypoxia in atherosclerotic lesions under conditions of insulin

  2. Bisphenol A Alters Autonomic Tone and Extracellular Matrix Structure and Induces Sex-Specific Effects on Cardiovascular Function in Male and Female CD-1 Mice

    PubMed Central

    Gear, Robin B.; Kendig, Eric L.

    2015-01-01

    The aim of this study was to determine whether bisphenol A (BPA) has adverse effects on cardiovascular functions in CD-1 mice and define sex-specific modes of BPA action in the heart. Dams and analyzed progeny were maintained on a defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) that resulted in BPA exposures from 4–5 to approximately 5000 μg/kg · d or a diet containing 17α-ethinyl estradiol (EE; ∼0.02, 0.2, and 0.15 μg/kg · d) as an oral bioavailable estrogen control. Assessment of electrocardiogram parameters using noninvasive methods found that ventricular functions in both male and female mice were not altered by either BPA or EE. However, exposure-related changes in the rates of ventricular contraction, suggestive of a shift in sympathovagal balance of heart rate control toward increased parasympathetic activity, were detected in males. Decreased systolic blood pressure was observed in males exposed to BPA above 5 μg/kg · d and in females from the highest BPA exposure group. Morphometric histological measures revealed sexually dimorphic changes in the composition of the cardiac collagen extracellular matrix, increases in fibrosis, and evidence of modest exposure-related remodeling. Experiments using the α-selective adrenergic agonist phenylephrine found that BPA enhanced reflex bradycardia in females, but not males, revealed that BPA and EE exposure sex specifically altered the sympathetic regulation of the baroreflex circuits. Increased sensitivity to the cardiotoxic effects of the β-adrenergic agonist isoproterenol was observed in BPA- and EE-exposed females. This effect was not observed in males, in which BPA or EE exposures were protective of isoproterenol-induced ischemic damage and hypertrophy. The results of RNA sequence analysis identified significant sex-specific changes in gene expression in response to BPA that were consistent with the observed exposure-related phenotypic changes in the collagenous and noncollagenous

  3. Cultural context moderates the relationship between emotion control values and cardiovascular challenge versus threat responses.

    PubMed

    Mauss, Iris B; Butler, Emily A

    2010-07-01

    Cultural context affects people's values regarding emotions, as well as their experiential and behavioral but not autonomic physiological responses to emotional situations. Little research, however, has examined how cultural context influences the relationships among values and emotional responding. Specifically, depending on their cultural context, individuals' values about emotion control (ECV; the extent to which they value emotion control) may have differing meanings, and as such, be associated with differing responses in emotional situations. We examined this possibility by testing the effect of two cultural contexts (28 female Asian-American (AA) versus 28 female European-American (EA) undergraduate students) on the associations between individuals' ECV and emotional responding (experiential, behavioral, and cardiovascular) to a relatively neutral film clip and a laboratory anger provocation. In the AA group, greater ECV were associated with reduced anger experience and behavior, and a challenge pattern of cardiovascular responding. In the EA group, greater ECV were associated with reduced anger behavior but not anger experience, and a threat pattern of cardiovascular responding. These results are consistent with the notion that individuals' values about emotion are associated with different meanings in different cultural contexts, and in turn, with different emotional and cardiovascular responses.

  4. Comparing Visible and Invisible Social Support: Non-evaluative Support Buffers Cardiovascular Responses to Stress.

    PubMed

    Kirsch, Julie A; Lehman, Barbara J

    2015-12-01

    Previous research suggests that in contrast to invisible social support, visible social support produces exaggerated negative emotional responses. Drawing on work by Bolger and colleagues, this study disentangled social support visibility from negative social evaluation in an examination of the effects of social support on negative emotions and cardiovascular responses. As part of an anticipatory speech task, 73 female participants were randomly assigned to receive no social support, invisible social support, non-confounded visible social support or visible social support as delivered in a 2007 study by Bolger and Amarel. Twelve readings, each for systolic blood pressure, diastolic blood pressure and heart rate were taken at 5-min intervals throughout the periods of baseline, reactivity and recovery. Cardiovascular outcomes were tested by incorporating a series of theoretically driven planned contrasts into tests of stress reactivity conducted through piecewise growth curve modelling. Linear and quadratic trends established cardiovascular reactivity to the task. Further, in comparison to the control and replication conditions, the non-confounded visible and invisible social support conditions attenuated cardiovascular reactivity over time. Pre- and post-speech negative emotional responses were not affected by the social support manipulations. These results suggest that appropriately delivered visible social support may be as beneficial as invisible social support.

  5. Cardiovascular response to apneic immersion in cool and warm water

    NASA Technical Reports Server (NTRS)

    Folinsbee, L.

    1974-01-01

    The influence of prior exposure to cool water and the influence of lung volume on the responses to breath holding were examined. The bradycardia and vasoconstriction that occur during breath-hold diving in man are apparently the resultant of stimuli from apnea, relative expansion of the thorax, lung volume, esophageal pressure, face immersion, and thermal receptor stimulation. It is concluded that the bradycardia and vasoconstriction associated with breath holding during body immersion are not attenuated by a preexisting bradycardia and vasoconstriction due to cold.

  6. Cardiovascular response to apneic immersion in cool and warm water

    NASA Technical Reports Server (NTRS)

    Folinsbee, L.

    1974-01-01

    The influence of prior exposure to cool water and the influence of lung volume on the responses to breath holding were examined. The bradycardia and vasoconstriction that occur during breath-hold diving in man are apparently the resultant of stimuli from apnea, relative expansion of the thorax, lung volume, esophageal pressure, face immersion, and thermal receptor stimulation. It is concluded that the bradycardia and vasoconstriction associated with breath holding during body immersion are not attenuated by a preexisting bradycardia and vasoconstriction due to cold.

  7. Cardiovascular activity in blood-injection-injury phobia during exposure: evidence for diphasic response patterns?

    PubMed

    Ritz, Thomas; Meuret, Alicia E; Simon, Erica

    2013-08-01

    Exposure to feared stimuli in blood-injection-injury (BII)-phobia is thought to elicit a diphasic response pattern, with an initial fight-flight-like cardiovascular activation followed by a marked deactivation and possible fainting (vasovagal syncope). However, studies have remained equivocal on the importance of such patterns. We therefore sought to determine the prevalence and clinical relevance of diphasic responses using criteria that require a true diphasic response to exceed cardiovascular activation of an emotional episode of a negative valence and to exceed deactivation of an emotionally neutral episode. Sixty BII-phobia participants and 20 healthy controls were exposed to surgery, anger and neutral films while measuring heart rate, blood pressure, respiratory pattern, and end-tidal partial pressure of carbon dioxide (as indicator of hyperventilation). Diphasic response patterns were observed in up to 20% of BII-phobia participants and 26.6% of healthy controls for individual cardiovascular parameters. BII-phobia participants with diphasic patterns across multiple parameters showed more fear of injections and blood draws, reported the strongest physical symptoms during the surgery film, and showed the strongest tendency to hyperventilate. Thus, although only a minority of individuals with BII phobia shows diphasic responses, their occurrence indicates significant distress. Respiratory training may add to the treatment of BII phobia patients that show diphasic response patterns.

  8. Cardiovascular responses associated with daily walking in subacute stroke.

    PubMed

    Prajapati, Sanjay K; Mansfield, Avril; Gage, William H; Brooks, Dina; McIlroy, William E

    2013-01-01

    Despite the importance of regaining independent ambulation after stroke, the amount of daily walking completed during in-patient rehabilitation is low. The purpose of this study is to determine if (1) walking-related heart rate responses reached the minimum intensity necessary for therapeutic aerobic exercise (40%-60% heart rate reserve) or (2) heart rate responses during bouts of walking revealed excessive workload that may limit walking (>80% heart rate reserve). Eight individuals with subacute stroke attending in-patient rehabilitation were recruited. Participants wore heart rate monitors and accelerometers during a typical rehabilitation day. Walking-related changes in heart rate and walking bout duration were determined. Patients did not meet the minimum cumulative requirements of walking intensity (>40% heart rate reserve) and duration (>10 minutes continuously) necessary for cardiorespiratory benefit. Only one patient exceeded 80% heart rate reserve. The absence of significant increases in heart rate associated with walking reveals that patients chose to walk at speeds well below a level that has meaningful cardiorespiratory health benefits. Additionally, cardiorespiratory workload is unlikely to limit participation in walking. Measurement of heart rate and walking during in-patient rehabilitation may be a useful approach to encourage patients to increase the overall physical activity and to help facilitate recovery.

  9. Cardiovascular Responses Associated with Daily Walking in Subacute Stroke

    PubMed Central

    Prajapati, Sanjay K.; Gage, William H.; McIlroy, William E.

    2013-01-01

    Despite the importance of regaining independent ambulation after stroke, the amount of daily walking completed during in-patient rehabilitation is low. The purpose of this study is to determine if (1) walking-related heart rate responses reached the minimum intensity necessary for therapeutic aerobic exercise (40%–60% heart rate reserve) or (2) heart rate responses during bouts of walking revealed excessive workload that may limit walking (>80% heart rate reserve). Eight individuals with subacute stroke attending in-patient rehabilitation were recruited. Participants wore heart rate monitors and accelerometers during a typical rehabilitation day. Walking-related changes in heart rate and walking bout duration were determined. Patients did not meet the minimum cumulative requirements of walking intensity (>40% heart rate reserve) and duration (>10 minutes continuously) necessary for cardiorespiratory benefit. Only one patient exceeded 80% heart rate reserve. The absence of significant increases in heart rate associated with walking reveals that patients chose to walk at speeds well below a level that has meaningful cardiorespiratory health benefits. Additionally, cardiorespiratory workload is unlikely to limit participation in walking. Measurement of heart rate and walking during in-patient rehabilitation may be a useful approach to encourage patients to increase the overall physical activity and to help facilitate recovery. PMID:23476892

  10. Agentic extraversion as a predictor of effort-related cardiovascular response.

    PubMed

    Kemper, Christoph J; Leue, Anja; Wacker, Jan; Chavanon, Mira-Lynn; Hennighausen, Erwin; Stemmler, Gerhard

    2008-05-01

    The present study examined an extraversion-based extension of the integrative model of cardiovascular effort regulation by Wright and Kirby [Wright, R.A., Kirby, L.D., 2001. Effort determination of cardiovascular response: an integrative analysis with applications in social psychology. In: Zanna, M.P. (Ed.), Advances in Experimental Social Psychology, Academic Press, San Diego, CA, pp. 255-307.]. This model explains cardiovascular effort reactivity in terms of task difficulty, ability appraisal, and success importance. Aggregate measures of cardiovascular variables (alpha-adrenergic, beta-adrenergic, and cholinergic activation components) were used to measure extraversion-based differences in effort. Subjects performed a sequential letter task (n-back verbal working memory task) with four levels of difficulty. Agentic extraverts (n=10) appraised their ability and happiness as significantly higher than introverts (n=10). Introverts showed the expected shark-fin shaped pattern of effort-related cardiovascular reactivity for the alpha-adrenergic and cholinergic activation components. Effort decreased after the moderately difficult 2-back task. Results provide first evidence for an extraversion-based extension of the model and are discussed with regard to mood and resource allocation as possible mechanisms.

  11. Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight

    NASA Technical Reports Server (NTRS)

    Baisch, F.; Beck, L.; Blomqvist, G.; Wolfram, G.; Drescher, J.; Rome, J. L.; Drummer, C.

    2000-01-01

    BACKGROUND: It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. METHODS: LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. RESULTS: Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. CONCLUSION: We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

  12. Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight.

    PubMed

    Baisch, F; Beck, L; Blomqvist, G; Wolfram, G; Drescher, J; Rome, J L; Drummer, C

    2000-12-01

    It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

  13. Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight

    NASA Technical Reports Server (NTRS)

    Baisch, F.; Beck, L.; Blomqvist, G.; Wolfram, G.; Drescher, J.; Rome, J. L.; Drummer, C.

    2000-01-01

    BACKGROUND: It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. METHODS: LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. RESULTS: Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. CONCLUSION: We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

  14. Impacts of fat from ruminants' meat on cardiovascular health and possible strategies to alter its lipid composition.

    PubMed

    Vargas-Bello-Pérez, Einar; Larraín, Rafael E

    2017-05-01

    In the last few decades there has been increased consumer interest in the fatty acid (FA) composition of ruminant meat due to its content of saturated FAs, which have been implicated in diseases associated with modern life. However, recent studies have questioned the recommendations to reduce intake of fat, saturated FAs and cholesterol as a means of reducing the risk of cardiovascular disease. Interestingly, ruminant meat has some bioactive lipids such as C18:1t11 and C18:2 c9, t11 which have been reported to have positive effects on human health. In order to improve muscle fat composition from a human health standpoint, oilseeds, plant oils and marine oils can be used in ruminant diets. On the other hand, molecular mechanisms play an important role in the alteration of the FA composition of muscle fat. Genetics offer a wide range of possibilities for improvement of muscle fat composition by identifying different loci underlying the expression of quantitative traits. While significant progress has been made in characterizing the influence of diet on the FA composition of ruminant meat, the use of genetic tools can favor genotypes that could maximize their genetic potential through the diet. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  15. Cardiovascular responses to railway noise during sleep in young and middle-aged adults.

    PubMed

    Tassi, Patricia; Saremi, Mahnaz; Schimchowitsch, Sarah; Eschenlauer, Arnaud; Rohmer, Odile; Muzet, Alain

    2010-03-01

    The aim of this study was to investigate the effects of nocturnal railway noise on cardiovascular reactivity in young (25.8 +/- 2.6 years) and middle-aged (52.2 +/- 2.5 years) adults during sleep. Thirty-eight subjects slept three nights in the laboratory at 1-week interval. They were exposed to 48 randomized pass-bys of Freight, Passenger and Automotive trains either at an 8-h equivalent sound level of 40 dBA (Moderate) and 50 dBA (High) or at a silent Control night. Heart rate response (HRR), heart response amplitude (HRA), heart response latency (HRL) and finger pulse response (FPR), finger pulse amplitude (FPA) and finger pulse latency (FPL) were recorded to measure cardiovascular reactivity after each noise onset and for time-matched pseudo-noises in the control condition. Results show that Freight trains produced the highest cardiac response (increased HRR, HRA and HRL) compared to Passenger and Automotive. But the vascular response was similar whatever the type of train. Juniors exhibited an increased HRR and HRA as compared to seniors, but there was no age difference on vasoconstriction, except a shorter FPL in seniors. Noise level produced dose-dependent effects on all the cardiovascular indices. Sleep stage at noise occurrence was ineffective for cardiac response, but FPA was reduced when noise occurred during REM sleep. In conclusion, our study is in favor of an important impact of nocturnal railway noise on the cardiovascular system of sleeping subjects. In the limit of the samples studied, Freight trains are the most harmful, probably more because of their special length (duration) than because of their speed (rise time).

  16. Prinzmetal's angina:reflex cardiovascular response during episode of pain.

    PubMed Central

    Perez-Gomez, F; Martin de Dios, R; Rey, J; Garcia Aguado, A

    1979-01-01

    Previous angiographic studies have shown that coronary spasm occurs in association with the variant angina described by Prinzmetal, confirming his original hypothesis. In this work we recorded the heart rate changes and the incidence of arrhythmias during variant angina. The patients were divided into two groups: anterior, with electrocardiographic signs of anterior ischaemia, and inferior, with changes in the inferior leads. There was a significant increase of heart rate during pain in anterior myocardial ischaemia and a significant decrease when the ischaemia was inferior. The incidence of ectopic arrhythmias during pain was significantly greater in patients with anterior ischaemia, but there was a high incidence of atrioventricular block in patients with inferior ischaemia. We suggest that these findings can be explained by different responses of the automatic nervous system to anterior and inferior acute myocardial ischaemia. Images PMID:475938

  17. Fatherhood alters behavioural and neural responsiveness in a spatial task.

    PubMed

    Franssen, C L; Bardi, M; Shea, E A; Hampton, J E; Franssen, R Adam; Kinsley, C H; Lambert, K G

    2011-11-01

    The hormones and experiences of pregnancy, parturition and lactation have been shown to dramatically remodel the female rat's hippocampus, potentially enhancing behaviours critical for meeting the increased demands of motherhood. Previous work in our laboratory has also suggested that pup exposure, apart from pregnancy and lactation, constitutes an important influence on ancillary maternal behaviour (e.g. foraging behaviour). In the present study, we press the parental model further by examining the effect of pup exposure on the hippocampus of males from a biparental mouse species, the California mice (Peromyscus californicus). Males were either Fathers (i.e. first-time fathers housed with a female from mating until 7 days after parturition), pup-exposed virgins (PEV; i.e. sexually naïve males briefly exposed to pups daily for 7 days) or Virgins (i.e. never exposed to females or pups). A dry-land maze (DLM), as used for assessing spatial learning, was employed to determine the foraging abilities of the males. The results indicated that, on the most challenging day of testing (i.e. acquisition day), California mouse Fathers demonstrated superior memory for the task compared to PEVs and Virgins. In addition to the behavioural data, significantly more fos-immunoreactivity was observed in the CA1, CA3 and dentate gyrus regions of the hippocampi of Fathers than PEVs or Virgins in response to the probe trial. Additionally, a trend for altered performance on the DLM was observed in the PEVs on the last day of testing, which was accompanied by the highest levels of nestin-immunoreactivity, an indicant of neuroplasticity, of the three groups. In summary, these data suggest that, in accordance with previous observations of maternal rats, the paternal brain is similarly influenced by parental experience, as demonstrated by accompanying modifications to relevant neurobiological and behavioural responses. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell

  18. Metabolic monosaccharides altered cell responses to anticancer drugs.

    PubMed

    Chen, Long; Liang, Jun F

    2012-06-01

    Metabolic glycoengineering has been used to manipulate the glycochemistry of cell surfaces and thus the cell/cell interaction, cell adhesion, and cell migration. However, potential application of glycoengineering in pharmaceutical sciences has not been studied until recently. Here, we reported that Ac(4)ManNAc, an analog of N-acetyl-D-mannosamine (ManNAc), could affect cell responses to anticancer drugs. Although cells from different tissues and organs responded to Ac(4)ManNAc treatment differently, treated cells with increased sialic acid contents showed dramatically reduced sensitivity (up to 130 times) to anti-cancer drugs as tested on various drugs with distinct chemical structures and acting mechanisms. Neither increased P-glycoprotein activity nor decreased drug uptake was observed during the course of Ac(4)ManNAc treatment. However, greatly altered intracellular drug distributions were observed. Most intracellular daunorubicin was found in the perinuclear region, but not the expected nuclei in the Ac(4)ManNAc treated cells. Since sialoglycoproteins and gangliosides were synthesized in the Golgi, intracellular glycans affected intracellular signal transduction and drug distributions seem to be the main reason for Ac(4)ManNAc affected cell sensitivity to anticancer drugs. It was interesting to find that although Ac(4)ManNAc treated breast cancer cells (MDA-MB-231) maintained the same sensitivity to 5-Fluorouracil, the IC(50) value of 5-Fluorouracil to the same Ac(4)ManNAc treated normal cells (MCF-10A) was increased by more than 20 times. Thus, this Ac(4)ManNAc treatment enlarged drug response difference between normal and tumor cells provides a unique opportunity to further improve the selectivity and therapeutic efficiency of anticancer drugs.

  19. Altered regional homogeneity and efficient response inhibition in restrained eaters.

    PubMed

    Dong, D; Lei, X; Jackson, T; Wang, Y; Su, Y; Chen, H

    2014-04-25

    Restrained eaters (REs) characterized by less efficient response inhibition are at risk for future onset of binge eating and bulimic pathology. Previous imaging studies investigating REs have been based on task-related functional magnetic resonance imaging (fMRI) and little is known about resting-state neural activity underlying restrained eating. To illuminate this issue, we investigated resting-state fMRI differences between REs (n=22) and unrestrained eaters (UREs) (n=30) using regional homogeneity (ReHo) analysis, which measures the temporal synchronization of spontaneous fluctuations. Samples were equated on body mass index (BMI) and caloric deprivation levels (i.e., 14±2.1h since last evening meal) before undergoing fMRI. Correlation analyses were performed between the ReHo index of identified regions and response inhibition based on stop-signal reaction time (SSRT) within each sample. Compared with UREs, REs showed more ReHo in brain regions associated with food reward (i.e., orbitofrontal cortex (OFC), dorsal-lateral prefrontal cortex (dlPFC)), attention (i.e., lingual gyrus, cuneus, inferior parietal lobule) and somatosensory functioning (i.e., paracentral lobule, anterior insula). In addition, ReHo values for the left dlPFC and left anterior insula, respectively, were negatively and positively correlated with SSRT among REs but not UREs. In concert with previous studies, these results suggest altered local synchronization may help to explain why dieting to maintain or lose weight often fails or increases risk for binge eating among REs. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Alterations of the Host Microbiome Affect Behavioral Responses to Cocaine

    PubMed Central

    Kiraly, Drew D.; Walker, Deena M.; Calipari, Erin S.; Labonte, Benoit; Issler, Orna; Pena, Catherine J.; Ribeiro, Efrain A.; Russo, Scott J.; Nestler, Eric J.

    2016-01-01

    Addiction to cocaine and other psychostimulants represents a major public health crisis. The development and persistence of addictive behaviors comes from a complex interaction of genes and environment - the precise mechanisms of which remain elusive. In recent years a surge of evidence has suggested that the gut microbiome can have tremendous impact on behavioral via the microbiota-gut-brain axis. In this study we characterized the influence of the gut microbiota on cocaine-mediated behaviors. Groups of mice were treated with a prolonged course of non-absorbable antibiotics via the drinking water, which resulted in a substantial reduction of gut bacteria. Animals with reduced gut bacteria showed an enhanced sensitivity to cocaine reward and enhanced sensitivity to the locomotor-sensitizing effects of repeated cocaine administration. These behavioral changes were correlated with adaptations in multiple transcripts encoding important synaptic proteins in the brain’s reward circuitry. This study represents the first evidence that alterations in the gut microbiota affect behavioral response to drugs of abuse. PMID:27752130

  1. Experimental hyperleptinemia in neonatal rats leads to selective leptin responsiveness, hypertension, and altered myocardial function.

    PubMed

    Samuelsson, Anne-Maj; Clark, James; Rudyk, Olena; Shattock, Michael J; Bae, Sung Eun; South, Timothy; Pombo, Joaquim; Redington, Kathrine; Uppal, Esna; Coen, Clive W; Poston, Lucilla; Taylor, Paul D

    2013-09-01

    The prevalence of obesity among pregnant women is increasing. Evidence from human cohort studies and experimental animals suggests that offspring cardiovascular and metabolic function is compromised through early life exposure to maternal obesity. Previously, we reported that juvenile offspring of obese rats develop sympathetically mediated hypertension associated with neonatal hyperleptinemia. We have now addressed the hypothesis that neonatal exposure to raised leptin in the immediate postnatal period plays a causal role. Pups from lean Sprague-Dawley rats were treated either with leptin (3 mg/kg IP) or with saline twice daily from postnatal day 9 to 15 to mimic the exaggerated postnatal leptin surge observed in offspring of obese dams. Cardiovascular function was assessed by radiotelemetry at 30 days, and 2 and 12 months. In juvenile (30 days) leptin-treated rats, hearts were heavier and night-time (active period) systolic blood pressure was raised (mm Hg; mean ± SEM: male leptin-treated, 132 ± 1 versus saline-treated, 119 ± 1, n=6, P<0.05; female leptin-treated, 132 ± 2 versus saline-treated, 119 ± 1, n=6, P<0.01), and the pressor response to restraint stress and leptin challenge increased compared with saline-treated rats. Heart rate variability demonstrated an increased low:high frequency ratio in 30-day leptin-treated animals, indicative of heightened sympathetic efferent tone. Echocardiography showed altered left ventricular structure and systolic function in 30-day female leptin versus saline-treated rats. These disorders persisted to adulthood. In isolated hearts, contractile function was impaired at 5 months in male leptin-treated rats. Exogenously imposed hyperleptinemia in neonatal rats permanently influences blood pressure and cardiac structure and function.

  2. Ethnic differences in cardiovascular responses to laboratory stress: a comparison between asian and white americans.

    PubMed

    Shen, Biing-Jiun; Stroud, Laura R; Niaura, Raymond

    2004-01-01

    Compared to other ethnic groups, Asian Americans show significantly lower rates of cardiovascular disease (CVD). We tested the hypothesis that Asian Americans would show reduced cardiovascular responses to laboratory stressors than Caucasians. Forty-three Asians (18 men, 25 women) and 77 Caucasians (36 men, 41 women) with a mean age of 24 years (SD = 3.93) participated in a stress reactivity protocol consisting of four tasks (speech, serial subtraction, mirror tracing, handgrip) while heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured. Asian Americans demonstrated overall lower reactivity across tasks for SBP F(1,117 = 7.48, p < .01) and a trend toward lower HR response F(1,117 = 3.18, p < .10). A significant ethnicity by task interaction was observed for HR reactivity F(3,351 = 2.94, p < .05) such that Caucasians showed greater responses for the subtraction task.

  3. Cardiovascular responses during free-diving in the sea.

    PubMed

    Marongiu, E; Crisafulli, A; Ghiani, G; Olla, S; Roberto, S; Pinna, M; Pusceddu, M; Palazzolo, G; Sanna, I; Concu, A; Tocco, F

    2015-04-01

    Cardiac output has never been assessed during free-diving diving in the sea. Knowledge of human diving response in this setting is therefore scarce. 3 immersions were performed by 7 divers: at depths of 10 m, 20 m and 30 m. Each test consisted of 3 apnea phases: descent, static and ascent. An impedance cardiograph provided data on stroke volume, heart rate and cardiac output. Mean blood pressure, arterial O2 saturation and blood lactate values were also collected. Starting from a resting value of 4.5±1.6 L∙min(-1), cardiac output at 10 m showed an increase up to 7.1±2.2 L∙min(-1) (p<0.01) during the descent, while conditions during the static and ascent phases remained unchanged. At 20 m cardiac output values were 7.3±2.4 L∙min(-1) and 6.7(±1).2 L∙min(-1) during ascent and descent, respectively (p<0.01), and 4.3±0.9 L∙min(-1) during static phase. At 30 m cardiac output values were 6.5±1.8 L∙min(-1) and 7.5±2 L∙min(-1) during descent and ascent, respectively (p<0.01), and 4.7±2.1 L∙min(-1) during static phase. Arterial O2 saturation decreased with increasing dive depth, reaching 91.1±3.4% (p<0.001 vs. rest) upon emergence from a depth of 30 m. Blood lactate values increased to 4.1±1.2 mmol∙L(-1) at the end of the 30 m dive (p<0.001 vs. rest). Results seem to suggest that simultaneous activation of exercise and diving response could lead to an absence of cardiac output reduction aimed at an oxygen-conserving effect.

  4. Human endothelial cell responses to cardiovascular inspired pulsatile shear stress

    NASA Astrophysics Data System (ADS)

    Watson, Matthew; Baugh, Lauren; Black, Lauren, III; Kemmerling, Erica

    2016-11-01

    It is well established that hemodynamic shear stress regulates blood vessel structure and the development of vascular pathology. This process can be studied via in vitro models of endothelial cell responses to pulsatile shear stress. In this study, a macro-scale cone and plate viscometer was designed to mimic various shear stress waveforms found in the body and apply these stresses to human endothelial cells. The device was actuated by a PID-controlled DC gear-motor. Cells were exposed to 24 hours of pulsatile shear and then imaged and stained to track their morphology and secretions. These measurements were compared with control groups of cells exposed to constant shear and no shear. The results showed that flow pulsatility influenced levels of secreted proteins such as VE-cadherin and neuroregulin IHC. Cell morphology was also influenced by flow pulsatility; in general cells exposed to pulsatile shear stress developed a higher aspect ratio than cells exposed to no flow but a lower aspect ratio than cells exposed to steady flow.

  5. Social support and networks: cardiovascular responses following recall on immigration stress among Chinese Americans.

    PubMed

    Lee, Yuen Shan Christine; Suchday, Sonia; Wylie-Rosett, Judith

    2015-04-01

    Social support has been shown to act as a buffer for cardiovascular responses to stress. However, little is known about how social support and networks are related to cardiovascular responses to immigration stress recall. The current study evaluated the impact of structural and functional support on cardiovascular reaction following immigrant stress recall provocation as well as the moderation effect of interdependent self-construal among first-generation Chinese immigrants. One hundred fifty Chinese immigrants were recruited in the New York Chinatown area. Participants completed questionnaires assessing their levels of social support and networks, and interdependent self-construal. Following adaptation, participants recalled a recent post-immigration stress-provoking situation. Cardiovascular measures were taken during adaptation, stressor task, and recovery period. Hierarchical multiple regression analysis was performed. Social network size and type, as well as perceived emotional support were positively predictive of systolic blood pressure (SBP) reactivity changes. Instrumental support seeking was a positive predictor of SBP and diastolic blood pressure (DBP) reactivity. The moderation effect between instrumental support seeking and interdependent self-construal were significantly predictive of DBP reactivity and recovery, suggesting that perceptions about themselves in relation to others is a crucial factor for determining whether support seeking is beneficial or not. Social support was not a direct buffer on cardiovascular responses to stress among Chinese immigrants. Chinese values of interdependence and collectivism may partly explain the disconfirming results. Still, when interdependent self-construal was taken into account, Chinese immigrants who had less interdependent self-construal, but solicited more instrumental support, had faster adaptation to stress over the long term.

  6. Social Support and Networks: Cardiovascular Responses Following Recall on Immigration Stress Among Chinese Americans

    PubMed Central

    Suchday, Sonia; Wylie-Rosett, Judith

    2014-01-01

    Social support has been shown to act as a buffer for cardiovascular responses to stress. However, little is known about how social support and networks are related to cardiovascular responses to immigration stress recall. The current study evaluated the impact of structural and functional support on cardiovascular reaction following immigrant stress recall provocation as well as the moderation effect of interdependent self-construal among first-generation Chinese immigrants. One hundred fifty Chinese immigrants were recruited in the New York Chinatown area. Participants completed questionnaires assessing their levels of social support and networks, and interdependent self-construal. Following adaptation, participants recalled a recent post-immigration stress-provoking situation. Cardiovascular measures were taken during adaptation, stressor task, and recovery period. Hierarchical multiple regression analysis was performed. Social network size and type, as well as perceived emotional support were positively predictive of systolic blood pressure (SBP) reactivity changes. Instrumental support seeking was a positive predictor of SBP and diastolic blood pressure (DBP) reactivity. The moderation effect between instrumental support seeking and interdependent self-construal were significantly predictive of DBP reactivity and recovery, suggesting that perceptions about themselves in relation to others is a crucial factor for determining whether support seeking is beneficial or not. Social support was not a direct buffer on cardiovascular responses to stress among Chinese immigrants. Chinese values of interdependence and collectivism may partly explain the disconfirming results. Still, when interdependent self-construal was taken into account, Chinese immigrants who had less interdependent self-construal, but solicited more instrumental support, had faster adaptation to stress over the long term. PMID:24288021

  7. Influence of passive stretch on muscle blood flow, oxygenation and central cardiovascular responses in healthy young males.

    PubMed

    Kruse, Nicholas T; Silette, Christopher R; Scheuermann, Barry W

    2016-05-01

    The aim of this study was to examine the effect of skeletal muscle stretching on peripheral, central, and autonomic cardiovascular responses in humans. Twelve healthy males completed a controlled passive stretch of the plantar flexors for 4 min at three different intensities. Doppler ultrasound velocimetry and imaging techniques assessed mean leg blood flow (MLBF), antegrade blood flow, and retrograde blood flow of the popliteal artery. Near-infrared spectroscopy assessed the concentration of deoxygenated hemoglobin + myoglobin ([HHb]) and the sum of its deoxygenated and oxygenated forms [i.e., blood volume ([Hbtot])]. Heart rate (HR) and mean arterial pressure were measured simultaneously to peripheral hemodynamic responses. During stretch there was an increase (P < 0.05) in antegrade and retrograde blood flow along with [HHb] and [Hbtot] relative to baseline, whereas MLBF was not altered. HR increased (P < 0.01) in a stretch intensity- and time-dependent manner, suggesting a threshold tension must be met that results in a mechanoreflex-mediated increase in HR. After stretch there was an increase (P < 0.05) in [Hbtot] and MLBF in each condition, suggesting that stretch creates a poststretch hyperemic response. Furthermore, retrograde blood flow was decreased (P < 0.05) after stretch in each stretch condition. Mean arterial pressure was decreased (P < 0.05) after moderate-intensity stretching. Collectively, our data provide novel mechanistic evidence on cardiovascular responses to skeletal muscle stretching in humans. Moreover, the reductions in MAP and retrograde blood flow suggest that stretch transiently reduces myogenic vascular tone in a poststretch resting period. Copyright © 2016 the American Physiological Society.

  8. A Proposed Study Examining Individual Differences in Temporal Profiles of Cardiovascular Responses to Head Down Tilt During Fluid Loading

    NASA Technical Reports Server (NTRS)

    Cowings, Patricia; Toscano, William; Winther, Sean; Martinez, Jacqueline; Dominguez, Margaret

    2012-01-01

    Susceptibility of healthy astronauts to orthostatic hypotension and presyncope is exacerbated upon return from spaceflight. The effect of altered gravity during space flight and planetary transition on human cardiovascular function is of critical importance to maintenance of astronaut health and safety. Hypovolemia, reduced plasma volume, is suspected to play an important role in cardiovascular deconditioning following exposure to spaceflight, which may lead to increased peripheral resistance, attenuated arterial baroreflex, and changes in cardiac function. A promising countermeasure for post-flight orthostatic intolerance is fluid loading used to restore lost plasma volume by giving crew salt tablets and water prior to re-entry. The main purpose of the proposed study is to define the temporal profile of cardiac responses to simulated 0-G conditions before and following a fluid loading countermeasure. 8 men and 8 women will be tested during 4 hour exposures at 6o head down tilt (HDT). Each subject will be given two exposures to HDT on separate days, one with and one without fluid loading (one liter of 0.9% saline solution). Stand tests (orthostatic stress) will be done before and after each HDT. Cardiac measures will be obtained with both impedance cardiography and echo ultrasound

  9. Blocking systemic nitric oxide production alters neuronal activation in brain structures involved in cardiovascular regulation during polymicrobial sepsis.

    PubMed

    Bruhn, Fernando Henrique Pascoti; Corrêa, Pollyanna Barbosa Farias; Oliveira-Pelegrin, Gabriela Ravanelli; Rocha, Maria José Alves

    2009-04-10

    In a previous study, we concluded that overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) in the late phase of sepsis prevents hypothalamic activation, blunts vasopressin secretion and contributes to hypotension, irreversible shock and death. The aim of this follow-up study was to evaluate if the same neuronal activation pattern happens in brain structures related to cardiovascular functions. Male Wistar rats received intraperitoneal injections of aminoguanidine, an iNOS inhibitor, or saline 30 min before cecal ligation and puncture (CLP) or sham surgeries. The animals were perfused 6 or 24h after the surgeries and the brains were removed and processed for Fos immunocytochemistry. We observed an increase (P<0.001) in c-fos expression 6h after CLP in the area postrema (AP), nucleus of the tractus solitarius (NTS), ventral lateral medulla (VLM), locus coeruleus (LC) and parabrachial nucleus (PB). At 24h after CLP, however, c-fos expression was strongly decreased in all these nuclei (P<0.05), except for the VLM. Aminoguanidine reduced c-fos expression in the AP and NTS at 6h after CLP, but showed an opposite effect at 24h, with an increase in the AP, NTS, and also in the VLM. No such effect was observed in the LC and PB at 6 or 24h. In all control animals, c-fos expression was minimal or absent. We conclude that in the early phase of sepsis iNOS-derived NO may be partially responsible for the activation of brain structures related to cardiovascular regulation. During the late phase, however, this activation is reduced or abolished.

  10. Evidence for Altered Alpha-Adrenoreceptor Responsiveness after a Single Bout of Maximal Exercise

    DTIC Science & Technology

    2003-07-01

    Evidence for altered - adrenoreceptor responsiveness after a single bout of maximal exercise Victor A. Convertino1 (With the Technical Assistance of...the hypothesis that adrenoreceptor responsiveness is altered within 24 h of the performance of maximal exercise . Adrenoreceptor responsiveness was...tested under two exper- imental conditions (with and without maximal exercise ). Adrenoreceptor tests were performed 24 h after each subject performed

  11. Abnormal cardiovascular response to exercise in hypertension: contribution of neural factors.

    PubMed

    Mitchell, Jere H

    2017-06-01

    During both dynamic (e.g., endurance) and static (e.g., strength) exercise there are exaggerated cardiovascular responses in hypertension. This includes greater increases in blood pressure, heart rate, and efferent sympathetic nerve activity than in normal controls. Two of the known neural factors that contribute to this abnormal cardiovascular response are the exercise pressor reflex (EPR) and functional sympatholysis. The EPR originates in contracting skeletal muscle and reflexly increases sympathetic efferent nerve activity to the heart and blood vessels as well as decreases parasympathetic efferent nerve activity to the heart. These changes in autonomic nerve activity cause an increase in blood pressure, heart rate, left ventricular contractility, and vasoconstriction in the arterial tree. However, arterial vessels in the contracting skeletal muscle have a markedly diminished vasoconstrictor response. The markedly diminished vasoconstriction in contracting skeletal muscle has been termed functional sympatholysis. It has been shown in hypertension that there is an enhanced EPR, including both its mechanoreflex and metaboreflex components, and an impaired functional sympatholysis. These conditions set up a positive feedback or vicious cycle situation that causes a progressively greater decrease in the blood flow to the exercising muscle. Thus these two neural mechanisms contribute significantly to the abnormal cardiovascular response to exercise in hypertension. In addition, exercise training in hypertension decreases the enhanced EPR, including both mechanoreflex and metaboreflex function, and improves the impaired functional sympatholysis. These two changes, caused by exercise training, improve the muscle blood flow to exercising muscle and cause a more normal cardiovascular response to exercise in hypertension. Copyright © 2017 the American Physiological Society.

  12. Female preproenkephalin-knockout mice display altered emotional responses.

    PubMed

    Ragnauth, A; Schuller, A; Morgan, M; Chan, J; Ogawa, S; Pintar, J; Bodnar, R J; Pfaff, D W

    2001-02-13

    The endogenous opioid system has been implicated in sexual behavior, palatable intake, fear, and anxiety. The present study examined whether ovariectomized female transgenic preproenkephalin-knockout (PPEKO) mice and their wild-type and heterozygous controls displayed alterations in fear and anxiety paradigms, sucrose intake, and lordotic behavior. To examine stability of responding, three squads of the genotypes were tested across seasons over a 20-month period. In a fear-conditioning paradigm, PPEKO mice significantly increased freezing to both fear and fear + shock stimuli relative to controls. In the open field, PPEKO mice spent significantly less time and traversed significantly less distance in the center of an open field than wild-type controls. Further, PPEKO mice spent significantly less time and tended to be less active on the light side of a dark-light chamber than controls, indicating that deletion of the enkephalin gene resulted in exaggerated responses to fear or anxiety-provoking environments. These selective deficits were observed consistently across testing squads spanning 20 months and different seasons. In contrast, PPEKO mice failed to differ from corresponding controls in sucrose, chow, or water intake across a range (0.0001-20%) of sucrose concentrations and failed to differ in either lordotic or female approach to male behaviors when primed with estradiol and progesterone, thereby arguing strongly for the selectivity of a fear and anxiety deficit which was not caused by generalized and nonspecific debilitation. These transgenic data strongly suggest that opioids, and particularly enkephalin gene products, are acting naturally to inhibit fear and anxiety.

  13. The role of neuropeptide Y in the ovine fetal cardiovascular response to reduced oxygenation

    PubMed Central

    Sanhueza, Emilia M; Johansen-Bibby, Anja A; Fletcher, Andrew J W; Riquelme, Raquel A; Daniels, Alejandro J; Serón-Ferré, Maria; Gaete, Cristián R; Carrasco, Jorge E; Llanos, Aníbal J; Giussani, Dino A

    2003-01-01

    This study investigated the role of neuropeptide Y (NPY) in mediating cardiovascular responses to reduced oxygenation in the late gestation ovine fetus by: (1) comparing the effects on the cardiovascular system of an exogenous infusion of NPY with those elicited by moderate or severe reductions in fetal oxygenation; and (2) determining the effect of fetal i.v. treatment with a selective NPY-Y1 receptor antagonist on the fetal cardiovascular responses to acute moderate hypoxaemia. Under general anaesthesia, 14 sheep fetuses (0.8–0.9 of gestation) were surgically prepared with vascular and amniotic catheters. In 5 of these fetuses, a Transonic flow probe was also implanted around a femoral artery. Following at least 5 days of recovery, one group of fetuses (n = 9) was subjected to a 30 min treatment period with exogenous NPY (17 μg kg−1 bolus plus 0.85 μg kg−1 min−1 infusion). In this group, fetal blood pressure and heart rate were monitored continuously and the distribution of the fetal combined ventricular output was assessed via injection of radiolabelled microspheres before and during treatment. The second group of fetuses instrumented with the femoral flow probe (n = 5) were subjected to a 3 h experiment consisting of 1 h of normoxia, 1 h of hypoxaemia, and 1 h of recovery during a slow i.v. infusion of vehicle. One or two days later, the acute hypoxaemia protocol was repeated during fetal i.v. treatment with a selective NPY-Y1 receptor antagonist (50 μg kg−1bolus + 1.5 μg kg−1 min−1 infusion). In these fetuses, fetal arterial blood pressure, heart rate and femoral vascular resistance were recorded continuously. The results show that fetal treatment with exogenous NPY mimics the fetal cardiovascular responses to asphyxia, and that treatment of the sheep fetus with a selective NPY-Y1 receptor antagonist does not affect the fetal cardiovascular response to acute moderate hypoxaemia. These results support a greater role for NPY in mediating the

  14. Habitual alcohol consumption is associated with lower cardiovascular stress responses--a novel explanation for the known cardiovascular benefits of alcohol?

    PubMed

    Jones, Alexander; McMillan, Merlin R; Jones, Russell W; Kowalik, Grzegorz T; Steeden, Jennifer A; Pruessner, Jens C; Taylor, Andrew M; Deanfield, John E; Muthurangu, Vivek

    2013-07-01

    In contrast to heavy alcohol consumption, which is harmful, light to moderate drinking has been linked to reduced cardiovascular morbidity and mortality. Effects on lipid status or clotting do not fully explain these benefits. Exaggerated cardiovascular responses to mental stress are detrimental to cardiovascular health. We hypothesized that habitual alcohol consumption might reduce these responses, with potential benefits. Advanced magnetic resonance techniques were used to accurately measure cardiovascular responses to an acute mental stressor (Montreal Imaging Stress Task) in 88 healthy adults (∼1:1 male:female). Salivary cortisol and task performance measures were used to assess endocrine and cognitive responses. Habitual alcohol consumption and confounding factors were assessed by questionnaire. Alcohol consumption was inversely related to responses of heart rate (HR) (r = -0.31, p = 0.01), cardiac output (CO) (r = -0.32, p = 0.01), vascular resistance (r = 0.25, p = 0.04) and mean blood pressure (r = -0.31, p = 0.01) provoked by stress, but not to stroke volume (SV), or arterial compliance changes. However, high alcohol consumers had greater cortisol stress responses, compared to moderate consumers (3.5 versus 0.7 nmol/L, p = 0.04). Cognitive measures did not differ. Findings were not explained by variations in age, sex, social class, ethnicity, physical activity, adrenocortical activity, adiposity, smoking, menstrual phase and chronic stress. Habitual alcohol consumption is associated with reduced cardiac responsiveness during mental stress, which has been linked to lower risk of hypertension and vascular disease. Consistent with established evidence, our findings suggest a mechanism by which moderate alcohol consumption might reduce cardiovascular disease, but not high consumption, where effects such as greater cortisol stress responses may negate any benefits.

  15. Dissecting the genetic architecture of the cardiovascular and renal stress response.

    PubMed

    Snieder, Harold; Harshfield, Gregory A; Barbeau, Paule; Pollock, David M; Pollock, Jennifer S; Treiber, Frank A

    2002-10-01

    We review the evidence for a genetic basis of the cardiovascular and renal stress response. A bio-behavioral model of stress-induced hypertension is presented that explains how repeated exposure to stress in combination with genetic susceptibility might lead to the development of hypertension. In this model, we focus on three underlying physiological systems that mediate the stress response of the heart, vasculature and kidney: the sympathetic nervous system (SNS), the renin-angiotensin-aldosterone system (RAAS) and the endothelial system (ES). We then review the evidence for a genetic influence on cardiovascular reactivity to psychological stress and stress-induced sodium retention using data from twin and family studies and a limited number of candidate gene studies. Finally, by describing the underlying physiological systems of our model and their genetic underpinning we emphasize the importance of inclusion of genetic measurements in any future studies testing the reactivity hypothesis.

  16. The effect of adrenal demedullation on cardiovascular responses to environmental stimulation in conscious rats.

    PubMed Central

    Borkowski, K. R.; Kelly, E.

    1986-01-01

    Circulating plasma adrenaline has been implicated in the facilitation of neurogenic pressor responses and development of hypertension. Bilateral adrenal demedullation in rats did not affect body weight, urine output, urinary electrolyte (Na+, K+ and Cl-) excretion, nor plasma corticosterone concentration, indicating the selective nature of the demedullation procedure. Adrenal demedullation did induce significant reductions in adrenal catecholamine content, plasma adrenaline levels, resting blood pressure and heart rate in conscious rats, but did not affect alerting-induced increases in blood pressure. The adrenal medulla and circulating plasma adrenaline appear to contribute to the maintenance of resting cardiovascular parameters, but would not appear to be involved in nor facilitate the cardiovascular responses to environmental stimulation. PMID:3742165

  17. Cardiovascular responses at the onset of exercise with partial neuromuscular blockade in cat and man.

    PubMed Central

    Iwamoto, G A; Mitchell, J H; Mizuno, M; Secher, N H

    1987-01-01

    1. In decerebrated cats the cardiovascular, heart rate and blood pressure responses to static muscle contractions were followed from the onset of stimulation of the cut L7-S1 ventral roots. Heart rate and blood pressure were also followed during maximal voluntary and electrically induced static muscle contractions in man using one leg. In both cat and man contractions were performed under control conditions and tubocurarine-induced neuromuscular blockade. 2. In the cat, heart rate and blood pressure increased 1.7 s after the onset of the contraction. No cardiovascular responses were seen when the muscle contraction was blocked by tubocurarine. 3. In man, both heart rate and blood pressure increased at the onset of voluntary contractions. Partial curarization reduced strength to 39% of control. The heart rate response was unaffected by tubocurarine while the blood pressure response was reduced from 61 to 32 mmHg. 4. Electrical stimulation of the muscles resulted in 75% of voluntary strength in man. The heart rate response was delayed one R-R interval in the electrocardiogram but was as large as during voluntary contractions. During partial curarization the heart rate response was significantly smaller and the blood pressure response was reduced from 11 to 8 mmHg. 5. In conclusion, processes in active muscles elicit an increase in heart rate and blood pressure which depends on the intensity of the muscle contraction developed. However, the immediate cardiovascular responses at the onset of voluntary muscle contractions cannot be accounted for by reflexes generated in the working muscles alone. Images Fig. 2 PMID:3656150

  18. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    NASA Technical Reports Server (NTRS)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  19. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    NASA Technical Reports Server (NTRS)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  20. Cardiovascular responses to static exercise in man: central and reflex contributions.

    PubMed Central

    Gandevia, S C; Hobbs, S F

    1990-01-01

    1. To assess the contributions of muscle chemoreflexes and central signals of motor command to cardiovascular to static exercise, blood pressure and heart rate were measured during three separate conditions: (i) isometric handgrip contractions, (ii) entrapment of metabolites produced by these contractions within the contracting muscles (chemoreflex effect), and (iii) attempted contractions of acutely paralysed muscles at three levels of effort (command effect). 2. The chemoreflex was assessed during circulatory occlusion applied as the contraction ceased. Paralysis was produced by local infusion of lignocaine distal to a sphygmomanometer cuff inflated above systolic pressure. 3. Blood pressure and heart rate increased progressively during isometric contraction of 33 and 50% maximal voluntary strength (for 120 and 75 s respectively). Muscle chemoreflexes during occlusion also increased blood pressure in proportion to the duration of contraction but did not increase heart rate. During attempted contraction of paralysed muscles at three measured levels of motor command, blood pressure and heart rate increased, but only heart rate was graded with the level of command. 4. The pattern of cardiovascular response for the muscle chemoreflex (as indicated by the ratio of the changes in heart rate and blood pressure) differed from that for isometric contractions and for motor commands in isolation. The pattern for contractions and for moderate but not high intensities of motor command was similar. 5. These data suggest that cardiovascular responses to moderate intensities of static contraction can be produced primarily by motor command, but that both motor command and muscle chemoreflexes contribute to cardiovascular responses at higher intensities of static exercise. When studied in isolation, central motor command and muscle chemoreflexes do not produce the same pattern of circulatory responses. PMID:2086762

  1. Cardiovascular Responses to Unilateral, Bilateral, and Alternating Limb Resistance Exercise Performed Using Different Body Segments.

    PubMed

    Moreira, Osvaldo C; Faraci, Lucas L; de Matos, Dihogo G; Mazini Filho, Mauro L; da Silva, Sandro F; Aidar, Felipe José; Hickner, Robert C; de Oliveira, Cláudia E P

    2017-03-01

    Moreira, OC, Faraci, LL, de Matos, DG, Mazini Filho, ML, da Silva, SF, Aidar, FJ, Hickner, RC, and de Oliveira, CEP. Cardiovascular responses to unilateral, bilateral and alternating limb resistance exercise performed using different body segments. J Strength Cond Res 31(3): 644-652, 2017-The aim of this study was to verify and compare the cardiovascular responses to unilateral, bilateral, and alternating limb resistance exercise (RE) performed using different body segments. Fifteen men experienced in RE were studied during biceps curls, barbell rows, and knee extension exercises when performed bilaterally, unilaterally, and using alternating limbs. The protocol consisted of 3 sets of 10 repetitions at 80% of 10 repetition maximum with 2-minute rest between sets. Heart rate (HR) and blood pressure (BP) were measured after the last repetition. There was a statistically significant increase in HR, systolic blood pressure (SBP), and rate pressure product (RPP), from rest to postexercise. The RPP was higher in the third set of all exercises and in all 3 forms of execution, when compared with the first set. Bilateral biceps curls caused a greater increase in RPP (first and second sets) and HR, compared with the same exercise performed unilaterally. Furthermore, the performance of bilateral biceps curls induced greater HR and RPP, in all sets, compared with bilateral knee extension and barbell rows. There was also a significantly higher SBP for the alternating second and third sets and also for the bilateral third set of the knee extensions as compared with the barbell rows. It was concluded from the data of this study that the cardiovascular response was increased from rest to postexercise in all forms of exercise, especially immediately after the third set of RE. For exercises performed bilaterally with the upper body (biceps curls), there was a greater cardiovascular response when compared with the same exercise performed unilaterally or with lower-body exercise

  2. Computational Models of the Cardiovascular System and Its Response to Microgravity

    NASA Technical Reports Server (NTRS)

    Kamm, Roger D.

    1999-01-01

    Computational models of the cardiovascular system are powerful adjuncts to ground-based and in-flight experiments. We will provide NSBRI with a model capable of simulating the short-term effects of gravity on cardiovascular function. The model from this project will: (1) provide a rational framework which quantitatively defines interactions among complex cardiovascular parameters and which supports the critical interpretation of experimental results and testing of hypotheses. (2) permit predictions of the impact of specific countermeasures in the context of various hypothetical cardiovascular abnormalities induced by microgravity. Major progress has been made during the first 18 months of the program: (1) We have developed an operational first-order computer model capable of simulating the cardiovascular response to orthostatic stress. The model consists of a lumped parameter hemodynamic model and a complete reflex control system. The latter includes cardiopulmonary and carotid sinus reflex limbs and interactions between the two. (2) We have modeled the physiologic stress of tilt table experiments and lower body negative pressure procedures (LBNP). We have verified our model's predictions by comparing them with experimental findings from the literature. (3) We have established collaborative efforts with leading investigators interested in experimental studies of orthostatic intolerance, cardiovascular control, and physiologic responses to space flight. (4) We have established a standardized method of transferring data to our laboratory from the ongoing NSBRI bedrest studies. We use this data to estimate input parameters to our model and compare our model predictions to actual data to further verify our model. (5) We are in the process of systematically simulating current hypotheses concerning the mechanism underlying orthostatic intolerance by matching our simulations to stand test data from astronauts pre- and post-flight. (6) We are in the process of developing a

  3. Computational Models of the Cardiovascular System and Its Response to Microgravity

    NASA Technical Reports Server (NTRS)

    Kamm, Roger D.

    1999-01-01

    Computational models of the cardiovascular system are powerful adjuncts to ground-based and in-flight experiments. We will provide NSBRI with a model capable of simulating the short-term effects of gravity on cardiovascular function. The model from this project will: (1) provide a rational framework which quantitatively defines interactions among complex cardiovascular parameters and which supports the critical interpretation of experimental results and testing of hypotheses. (2) permit predictions of the impact of specific countermeasures in the context of various hypothetical cardiovascular abnormalities induced by microgravity. Major progress has been made during the first 18 months of the program: (1) We have developed an operational first-order computer model capable of simulating the cardiovascular response to orthostatic stress. The model consists of a lumped parameter hemodynamic model and a complete reflex control system. The latter includes cardiopulmonary and carotid sinus reflex limbs and interactions between the two. (2) We have modeled the physiologic stress of tilt table experiments and lower body negative pressure procedures (LBNP). We have verified our model's predictions by comparing them with experimental findings from the literature. (3) We have established collaborative efforts with leading investigators interested in experimental studies of orthostatic intolerance, cardiovascular control, and physiologic responses to space flight. (4) We have established a standardized method of transferring data to our laboratory from the ongoing NSBRI bedrest studies. We use this data to estimate input parameters to our model and compare our model predictions to actual data to further verify our model. (5) We are in the process of systematically simulating current hypotheses concerning the mechanism underlying orthostatic intolerance by matching our simulations to stand test data from astronauts pre- and post-flight. (6) We are in the process of developing a

  4. Autonomic cardiovascular responses in acclimatized lowlanders on prolonged stay at high altitude: a longitudinal follow up study.

    PubMed

    Dhar, Priyanka; Sharma, Vijay K; Hota, Kalpana B; Das, Saroj K; Hota, Sunil K; Srivastava, Ravi B; Singh, Shashi B

    2014-01-01

    Acute exposure to hypobaric hypoxia at high altitude is reported to cause sympathetic dominance that may contribute to the pathophysiology of high altitude illnesses. The effect of prolonged stay at high altitude on autonomic functions, however, remains to be explored. Thus, the present study aimed at investigating the effect of high altitude on autonomic neural control of cardiovascular responses by monitoring heart rate variability (HRV) during chronic hypobaric hypoxia. Baseline electrocardiography (ECG) data was acquired from the volunteers at mean sea level (MSL) (<250 m) in Rajasthan. Following induction of the study population to high altitude (4500-4800 m) in Ladakh region, ECG data was acquired from the volunteers after 6 months (ALL 6) and 18 months of induction (ALL 18). Out of 159 volunteers who underwent complete investigation during acquisition of baseline data, we have only included the data of 104 volunteers who constantly stayed at high altitude for 18 months to complete the final follow up after 18 months. HRV parameters, physiological indices and biochemical changes in serum were investigated. Our results show sympathetic hyperactivation along with compromise in parasympathetic activity in ALL 6 and ALL 18 when compared to baseline data. Reduction of sympathetic activity and increased parasympathetic response was however observed in ALL 18 when compared to ALL 6. Our findings suggest that autonomic response is regulated by two distinct mechanisms in the ALL 6 and ALL 18. While the autonomic alterations in the ALL 6 group could be attributed to increased sympathetic activity resulting from increased plasma catecholamine concentration, the sympathetic activity in ALL 18 group is associated with increased concentration of serum coronary risk factors and elevated homocysteine. These findings have important clinical implications in assessment of susceptibility to cardio-vascular risks in acclimatized lowlanders staying for prolonged duration at high

  5. Autonomic Cardiovascular Responses in Acclimatized Lowlanders on Prolonged Stay at High Altitude: A Longitudinal Follow Up Study

    PubMed Central

    Dhar, Priyanka; Sharma, Vijay K.; Hota, Kalpana B.; Das, Saroj K.; Hota, Sunil K.; Srivastava, Ravi B.; Singh, Shashi B.

    2014-01-01

    Acute exposure to hypobaric hypoxia at high altitude is reported to cause sympathetic dominance that may contribute to the pathophysiology of high altitude illnesses. The effect of prolonged stay at high altitude on autonomic functions, however, remains to be explored. Thus, the present study aimed at investigating the effect of high altitude on autonomic neural control of cardiovascular responses by monitoring heart rate variability (HRV) during chronic hypobaric hypoxia. Baseline electrocardiography (ECG) data was acquired from the volunteers at mean sea level (MSL) (<250 m) in Rajasthan. Following induction of the study population to high altitude (4500–4800 m) in Ladakh region, ECG data was acquired from the volunteers after 6 months (ALL 6) and 18 months of induction (ALL 18). Out of 159 volunteers who underwent complete investigation during acquisition of baseline data, we have only included the data of 104 volunteers who constantly stayed at high altitude for 18 months to complete the final follow up after 18 months. HRV parameters, physiological indices and biochemical changes in serum were investigated. Our results show sympathetic hyperactivation along with compromise in parasympathetic activity in ALL 6 and ALL 18 when compared to baseline data. Reduction of sympathetic activity and increased parasympathetic response was however observed in ALL 18 when compared to ALL 6. Our findings suggest that autonomic response is regulated by two distinct mechanisms in the ALL 6 and ALL 18. While the autonomic alterations in the ALL 6 group could be attributed to increased sympathetic activity resulting from increased plasma catecholamine concentration, the sympathetic activity in ALL 18 group is associated with increased concentration of serum coronary risk factors and elevated homocysteine. These findings have important clinical implications in assessment of susceptibility to cardio-vascular risks in acclimatized lowlanders staying for prolonged duration at high

  6. Cardiovascular and autonomic responses to whole-body cryostimulation in essential hypertension.

    PubMed

    Zalewski, Pawel; Buszko, Katarzyna; Zawadka-Kunikowska, Monika; Słomko, Joanna; Szrajda, Justyna; Klawe, Jacek J; Tafil-Klawe, Malgorzata; Sinski, Maciej; Newton, Julia

    2014-10-01

    Over recent years, a considerable increase in the popularity of cryostimulation and whole body cryotherapy (WBC) procedures has occurred both among healthy individuals and in various groups of patients, including those with primary untreated hypertension. The aim of this study was to compare the effects of WBC on the functional parameters of cardiovascular system in normotensive and primarily hypertensive individuals. The study included 26 young male volunteers with normal blood pressure range (NormoBP) and 13 with essential arterial hypertension (HyperBP). Each subject was exposed to cryotherapeutic factor (whole-body cryotherapy/cryostimulation, WBC) at a temperature of approximately -115°C to -125°C for a period of 3 min. The cardiovascular and autonomic parameters were measured noninvasively with Task Force® Monitor. Measurements in a supine position and tilt test were performed "before WBC" and "after WBC". Our study revealed that cryogenic temperatures exert strong modulatory effect on the cardiovascular system. Both groups showed adaptive changes of myocardial and vascular parameters in response to rapid cooling of virtually the whole body surface. While the profiles of some of these changes were similar in both the groups, also several considerable intergroup differences were documented. Consequently, the cryostimulation and cryotherapy treatment should be prescribed carefully to individuals who present with cardiovascular failure of any degree.

  7. Reproducibility of exercise-induced modulation of cardiovascular responses to cold stress.

    PubMed

    Rashed, H M; Leventhal, G; Madu, E C; Reddy, R; Cardoso, S

    1997-04-01

    The modulation of cardiovascular responses to the cold pressor test (CPT) as produced by exercise was studied in 13 volunteers. The reproducibility of the measurements selected for the study, i.e. heart rate (HR), blood pressure (BP), blood flow (BF) and skin temperature (ST), was investigated through repeat experiments in the fall of 1994 and the winter of 1995. HR was monitored before, during and after a 10-min period of bicycling at 70% of reserve HR. BP, cutaneous BF and ST were measured before and after exercise. Two CPTs (hand into ice-cold water for 1 min) were performed: one preceding exercise and another at 3 min after exercise. The results obtained allow us to conclude that in non-hypertensive volunteers (1) the pronounced cardiovascular responses (ST, BF and BP) induced by CPT are reproducible (p > 0.2) when compared to basal level values and (2) cardiovascular responses to cold stress are significantly attenuated by exercise (p < 0.03). Our study, therefore, supports and validates the use of our coupled exercise-CPT method in ongoing epidemiological studies attempting to identify individuals at risk for the development of hypertension as well as those most likely to benefit from preventative exercise programs.

  8. Cardiovascular and metabolic responses of hypertensive and normotensive rats to one week of cold exposure.

    PubMed

    Chambers, J B; Williams, T D; Nakamura, A; Henderson, R P; Overton, J M; Rashotte, M E

    2000-10-01

    Challenges to energy homeostasis, such as cold exposure, can have consequences for both metabolic and cardiovascular functioning. We hypothesized that 1-wk cold exposure (4 degrees C) would produce concurrent increases in metabolic rate (VO(2); indirect calorimetry), heart rate (HR), and mean arterial blood pressure (MAP) measured by telemetry. In the initial hours of change in ambient temperature (T(a)), both spontaneously hypertensive rats (SHRs) and normotensive Sprague-Dawley rats showed rapid increases (in cold) or decreases (in rewarming) of VO(2), HR, and MAP, although the initial changes in MAP and HR were more exaggerated in SHRs. Throughout cold exposure, HR, VO(2), food intake, and locomotor activity remained elevated but MAP decreased in both strains, particularly in the SHR. During rewarming, all measures normalized quickly in both strains except MAP, which fell below baseline (hypotension) for the first few days. The results indicate that variations of T(a) produce rapid changes in a suite of cardiovascular and behavioral responses that have many similarities in hypertensive and normotensive strains of rats. The findings are consistent with the general concept that the cardiovascular responses to cold exposure in rats are closely related to and perhaps a secondary consequence of the mechanisms responsible for increasing heat production.

  9. Role of periaqueductal gray on the cardiovascular response evoked by disinhibition of the dorsomedial hypothalamus.

    PubMed

    da Silva, Luiz Gonzaga; de Menezes, Rodrigo Cunha Alvim; dos Santos, Robson Augusto Souza; Campagnole-Santos, Maria Jose; Fontes, Marco Antonio Peliky

    2003-09-12

    Activation of neurons in the region of the dorsomedial hypothalamus (DMH), by microinjection of the GABA(A) receptor antagonist bicuculline methiodide (BMI) results in increases in arterial pressure, heart rate as well as behavioral changes similar to those evoked by acute emotional stress. Previous anatomic studies clearly demonstrated projections from the DMH to the midbrain periaqueductal gray (PAG), a brain region implicated in the organization of behavioral strategies associated with specific cardiovascular responses. In this study, physiological experiments in conscious rats were used to investigate the functional significance of this pathway. Unilateral inhibition of the lateral dorsolateral region of the PAG (l/dlPAG) with the GABA(A) receptor agonist, muscimol (1 nmol/100 nl) largely reduced the tachycardia and the pressor response produced by microinjection of BMI (10 pmol/100 nl) into the ipsilateral DMH. In contrast, inhibition of the ventrolateral PAG (vlPAG) region had no significant effect on the cardiovascular response evoked from disinhibition of the ipsilateral DMH. Our present results indicate that the l/dlPAG region is an important synaptic relay in the descending cardiovascular pathways from the DMH.

  10. The energetic and cardiovascular response to treadmill walking and cycle ergometer exercise in obese women.

    PubMed

    Lafortuna, Claudio L; Agosti, Fiorenza; Galli, Raffaela; Busti, Carlo; Lazzer, Stefano; Sartorio, Alessandro

    2008-08-01

    Physical activity is essential in obesity management, but exercise capacity is compromised in obese individuals due to the excessive body mass, impacting on body movement's energetics, and to the dysfunctions of regulatory mechanisms, affecting cardiovascular responses. This study aims to compare the energetics and cardiovascular responses of walking and cycling in obese women, and to formulate recommendations regarding the most suitable type of exercise for obesity. Fifteen obese (OB) and six normal weight (NW) women exercised on treadmill (TM) and cycle ergometer (CE). During both exercise modalities, metabolic rate was higher in OB than in NW and correlated with measures of body mass. Leg movement metabolic rate during cycling depended upon individual adiposity, and when accounted for, mechanical efficiency was similar in the two groups. When accounting for extra mass, differences in metabolic rate among groups are abolished for CE, indicating no obesity impairment of muscle efficiency, but not for TM, suggesting that differences in biomechanics may explain the higher net cost of transport of OB. In both groups, HR was higher during CE than TM at the same oxygen uptake (VO(2)), but in OB the HR increment over VO(2) was greater for CE than for TM. Therefore, due to different cardiovascular responses to TM and CE in OB, walking is more convenient, enabling OB to attain target energy expenditure at lower HR or in a shorter time.

  11. Immune, endocrine and cardiovascular responses to controllable and uncontrollable acute stress.

    PubMed

    Isowa, Tokiko; Ohira, Hideki; Murashima, Seikou

    2006-02-01

    This study, using a triadic-yoked design, clarified the effects of controllability of acute stress on responses of immune, cardiovascular (heart rate and blood pressure), and cortisol activities. Forty-three women in their follicular phase completed a mental arithmetic task as a stressor in which controllability was manipulated by correct or yoked-bogus feedback. The task decreased proportions of CD3+ T cells, CD4+ T cells, and CD19+ B cells, whereas it increased the numbers of white blood cells, lymphocytes, natural killer (NK) cells, and NK cell activity (NKCA). Our main hypothesis that greater immune and cardiovascular responses to the task would be obtained under the uncontrollable condition than under the controllable condition was not supported. However, the uncontrollable stress condition, but not the controllable situation, led to higher correlations between heart rate or blood pressure, and various immune parameters. On the other hand, parameters of heart rate variability reflecting sympathetic and parasympathetic activities showed significant correlations only with NKCA. These results suggest that immune responses were most directly associated with cardiovascular activities under the uncontrollable condition.

  12. Does heat stress alter the pig's response to dietary fat?

    PubMed

    Kellner, T A; Baumgard, L H; Prusa, K J; Gabler, N K; Patience, J F

    2016-11-01

    PFTN; = 0.624). Jowl IV at market increased with increasing degree of unsaturation of the dietary fat (68.5 g/100 g for CNTR, 68.2 g/100 g for TAL, and 71.5 g/100 g for CO; < 0.001). Heat stress decreased mRNA abundance of and ( ≤ 0.041). Heat stress and CO increased mRNA abundance of ( ≤ 0.047), and CO increased abundance of ( = 0.011). In conclusion, HS does not alter the pig's response to dietary fat. However, HS leads to reduced ADG, ADFI, G:F, and caloric efficiency and a suppression of mRNA abundance of genes involved in the lipolytic cascade, which resulted in a phenotype that was fatter than PFTN.

  13. Altering dietary lysine: arginine ratio has little effect on cardiovascular risk factors and vascular reactivity in moderately hypercholesterolemic adults

    USDA-ARS?s Scientific Manuscript database

    Background: The effect of dietary protein type on cardiovascular risk factors and vascular reactivity, with specific focus on the lysine to arginine (Lys:Arg) ratio, has been studied sporadically. Objective: Determine effect of dietary Lys:Arg ratio on cardiovascular risk factors and vascular reacti...

  14. Effect of Pregabalin on Cardiovascular Responses to Exercise and Postexercise Pain and Fatigue in Fibromyalgia: A Randomized, Double-Blind, Crossover Pilot Study

    PubMed Central

    White, Andrea T.; Light, Kathleen C.; Bateman, Lucinda; Hughen, Ronald W.; Vanhaitsma, Timothy A.; Light, Alan R.

    2015-01-01

    Pregabalin, an approved treatment for fibromyalgia (FM), has been shown to decrease sympathetic nervous system (SNS) activity and inhibit sympathetically maintained pain, but its effects on exercise responses have not been reported. Methods. Using a randomized double-blind crossover design, we assessed the effect of 5 weeks of pregabalin (versus placebo) on acute cardiovascular and subjective responses to moderate exercise in 19 FM patients. Blood pressure (BP), heart rate (HR), and ratings of perceived exertion (RPE) during exercise and ratings of pain, physical fatigue, and mental fatigue before, during, and for 48 hours after exercise were compared in patients on pregabalin versus placebo and also versus 18 healthy controls. Results. On placebo, exercise RPE and BP were significantly higher in FM patients than controls (p < 0.04). Pregabalin responders (n = 12, defined by patient satisfaction and symptom changes) had significantly lower exercise BP, HR, and RPE on pregabalin versus placebo (p < 0.03) and no longer differed from controls (p > 0.26). Cardiovascular responses of nonresponders (n = 7) were not altered by pregabalin. In responders, pregabalin improved ratings of fatigue and pain (p < 0.04), but negative effects on pain and fatigue were seen in nonresponders. Conclusions. These preliminary findings suggest that pregabalin may normalize cardiovascular and subjective responses to exercise in many FM patients. PMID:27026828

  15. Plastic alteration of vestibulo-cardiovascular reflex induced by 2 weeks of 3-G load in conscious rats.

    PubMed

    Abe, Chikara; Tanaka, Kunihiko; Awazu, Chihiro; Chen, Huayue; Morita, Hironobu

    2007-08-01

    Previous studies conducted in our laboratory have demonstrated that the vestibular system plays a significant role in controlling arterial pressure (AP) in conscious rats under conditions of transient microgravity. The vestibular system is known to be highly plastic, and on exposure to different gravitational environments, the sensitivity of the vestibular system-mediated AP response might be altered. In order to test this hypothesis, rats were maintained in a 3-G or a normal 1-G environment for 2 weeks, and the AP responses to free drop-induced microgravity were determined. In 1-G rats, the microgravity increased the AP by 37 +/- 3 mmHg; this pressor response was significantly attenuated by vestibular lesion (VL) (24 +/- 3 mmHg) or body stabilization (29 +/- 2 mmHg). Thus, the microgravity-induced pressor response was mediated by both the vestibular and nonvestibular systems; the input of the latter system was blocked by body stabilization. In the 3-G rats, the pressor responses were significantly suppressed compared to those in the corresponding 1-G rats; i.e., the AP increased by 24 +/- 2 mmHg in freely moving 3-G rats, by 10 +/- 4 mmHg in 3-G rats with VL, and by 13 +/- 4 mmHg in stabilized 3-G rats. Furthermore, there was no difference between the 1- and 3-G rats in terms of the pressor response induced by stressors such as a loud noise or an air jet. These results indicate that pre-exposure to 3-G for 2 weeks induces plasticity in both the vestibular- and nonvestibular-mediated AP responses to microgravity.

  16. Spaceflight Did Not Impair Cardiovascular Responses to Upright Posture in an Elderly Astronaut

    NASA Technical Reports Server (NTRS)

    Rossum, Alfred C.; Ziegler, Michael G.; Meck, Janice V.

    2001-01-01

    Some of the cardiovascular changes associated with spaceflight have similarities to those associated with aging. We studied the neuroendocrine and hemodynamic responses to upright posture in a 77 year old astronaut before and after spaceflight and compared them to those of a group of 20 younger (41 plus or minus 1 years) astronauts. While arterial pressure responses to standing were similar between the young and old astronauts, hemodynamic profiles were quite different. The elderly astronaut achieved adequate standing arterial pressure primarily by maintaining stroke volume and thus cardiac output. In spite of very high norepinephrine release, he had very little increase in heart rate or total peripheral resistance. This pattern persisted on all test occasions. These responses suggest high sympathetic responses, down-regulated adrenergic receptors and decreased venous compliance typical of aging. In contrast, younger astronauts did not maintain stroke volume or cardiac output with standing, but had significant increases in heart rate and resistance. These results suggest that this elderly subject had cardiovascular responses to standing that are expected in an aged person. These responses were not deleteriously affected by spaceflight. We suggest that healthy, fit elderly individuals are able to withstand the stresses of extreme environments and are not necessarily limited in their activities simply due to their chronological age.

  17. Indomethacin abolishes core temperature, but not cardiovascular or renal, responses to lipopolysaccharide in conscious lambs.

    PubMed

    Smith, Francine G; Fewell, James E; Qi, Wei

    2011-08-01

    1. Core temperature (Tc), cardiovascular and renal responses to lipopolysaccharide (LPS), as well as the role of endogenously produced prostaglandins (PG) in influencing these responses, were investigated in the present study in conscious, chronically instrumented lambs. 2. Core temperature, mean arterial pressure, heart rate (HR), renal blood flow (RBF) and several parameters of renal function were measured for 30 min before and for 5 h after intravenous injection of 0.03 μg/kg of the LPS Salmonella abortus equi (n = 9) or saline vehicle (n = 9). 3. After injection of LPS, Tc increased with a latency of 40 min, duration of 130 min and magnitude of 1.5°C. Mean arterial pressure increased within 110 min of LPS injection and then decreased below baseline within 5 h, concomitant with an increase in HR. There was a sustained increase in RBF after LPS injection and a significant increase in urinary flow rate, as well as Na(+) and Cl(-) excretion. 4. To determine the role of PGs in the responses to LPS observed, additional experiments were performed in another group of conscious lambs that had been pretreated with the non-selective cyclo-oxygenase inhibitor indomethacin (10 mg/kg; n = 6). 5. Although indomethacin abolished the Tc response to LPS, it had no significant effect on the cardiovascular and renal responses to LPS. There were no effects of saline vehicle on any of the variables measured. 6. These data provide evidence that, in conscious young lambs, cardiovascular and renal responses to LPS do not appear to be mediated by endogenously produced PGs and that they are independent of pyrogen-induced changes in Tc. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

  18. Network-based association of hypoxia-responsive genes with cardiovascular diseases

    NASA Astrophysics Data System (ADS)

    Wang, Rui-Sheng; Oldham, William M.; Loscalzo, Joseph

    2014-10-01

    Molecular oxygen is indispensable for cellular viability and function. Hypoxia is a stress condition in which oxygen demand exceeds supply. Low cellular oxygen content induces a number of molecular changes to activate regulatory pathways responsible for increasing the oxygen supply and optimizing cellular metabolism under limited oxygen conditions. Hypoxia plays critical roles in the pathobiology of many diseases, such as cancer, heart failure, myocardial ischemia, stroke, and chronic lung diseases. Although the complicated associations between hypoxia and cardiovascular (and cerebrovascular) diseases (CVD) have been recognized for some time, there are few studies that investigate their biological link from a systems biology perspective. In this study, we integrate hypoxia genes, CVD genes, and the human protein interactome in order to explore the relationship between hypoxia and cardiovascular diseases at a systems level. We show that hypoxia genes are much closer to CVD genes in the human protein interactome than that expected by chance. We also find that hypoxia genes play significant bridging roles in connecting different cardiovascular diseases. We construct a hypoxia-CVD bipartite network and find several interesting hypoxia-CVD modules with significant gene ontology similarity. Finally, we show that hypoxia genes tend to have more CVD interactors in the human interactome than in random networks of matching topology. Based on these observations, we can predict novel genes that may be associated with CVD. This network-based association study gives us a broad view of the relationships between hypoxia and cardiovascular diseases and provides new insights into the role of hypoxia in cardiovascular biology.

  19. Dose-response study of N,N-dimethyltryptamine in humans. I. Neuroendocrine, autonomic, and cardiovascular effects.

    PubMed

    Strassman, R J; Qualls, C R

    1994-02-01

    To begin applying basic neuropharmacological hypotheses of hallucinogenic drug actions to humans, we generated dose-response data for intravenously administered dimethyltryptamine fumarate's (DMT) neuroendocrine, cardiovascular, autonomic, and subjective effects in a group of experienced hallucinogen users. Dimethyltryptamine, an endogenous mammalian hallucinogen and drug of abuse, was administered intravenously at 0.05, 0.1, 0.2, and 0.4 mg/kg to 11 experienced hallucinogen users, in a double-blind, saline placebo-controlled, randomized design. Treatments were separated by at least 1 week. Peak DMT blood levels and subjective effects were seen within 2 minutes after drug administration, and were negligible at 30 minutes. Dimethyltryptamine dose dependently elevated blood pressure, heart rate, pupil diameter, and rectal temperature, in addition to elevating blood concentrations of beta-endorphin, corticotropin, cortisol, and prolactin. Growth hormone blood levels rose equally in response to all doses of DMT, and melatonin levels were unaffected. Threshold doses for significant effects relative to placebo were also hallucinogenic (0.2 mg/kg and higher). Subjects with five or more exposures to 3,4-methylenedioxymethamphetamine demonstrated less robust pupil diameter effects than those with two or fewer exposures. Dimethyltryptamine can be administered safely to experienced hallucinogen users and dose-response data generated for several measures hypothesized under serotonergic modulatory control. Additional studies characterizing the specific mechanisms mediating DMT's biological effects may prove useful in psychopharmacological investigations of drug-induced and endogenous alterations in brain function.

  20. Disruption of Responding Maintained by Conditioned Reinforcement: Alterations in Response-Conditioned-Reinforcer Relations

    ERIC Educational Resources Information Center

    Lieving, Gregory A.; Reilly, Mark P.; Lattal, Kennon A.

    2006-01-01

    An observing procedure was used to investigate the effects of alterations in response-conditioned-reinforcer relations on observing. Pigeons responded to produce schedule-correlated stimuli paired with the availability of food or extinction. The contingency between observing responses and conditioned reinforcement was altered in three experiments.…

  1. Loneliness accentuates age differences in cardiovascular responses to social evaluative threat.

    PubMed

    Ong, Anthony D; Rothstein, Jeremy D; Uchino, Bert N

    2012-03-01

    The effects of aging and loneliness on cardiovascular stress responses were examined in 91 young (18-30 years) and 91 older (65-80 years) normotensive adults. Participants completed the revised UCLA Loneliness Scale and a modified version of the Trier Social Stress Test. Piece-wise linear growth-curve analysis was used to model group differences in resting, reactivity, and recovery levels of systolic blood pressure (SBP) and diastolic blood pressure (DBP). Replicating and extending prior research, analyses revealed age-related increases in resting SBP and DBP. Adjusting for demographics and health covariates, interactions were found for SBP in which age differences in stress reactivity and recovery were greater among lonely than nonlonely participants. Findings provide further evidence that loneliness interacts with age to augment cardiovascular risk to social evaluative threat.

  2. Effect of hot flushes on cardiovascular autonomic responsiveness: a randomized controlled trial on hormone therapy.

    PubMed

    Hautamäki, Hanna; Haapalahti, Petri; Piirilä, Päivi; Tuomikoski, Pauliina; Sovijärvi, Anssi; Ylikorkala, Olavi; Mikkola, Tomi S

    2012-07-01

    To compare the responses of heart rate and blood pressure to various autonomic tests in women with and without pre-treatment hot flushes during estradiol and estradiol+medroxyprogesterone acetate (MPA) use. Hundred and fifty recently postmenopausal women (72 with and 78 without hot flushes) were randomized to receive transdermal estradiol (1mg/day), oral estradiol (2 mg/day) alone or in combination with MPA (5mg/day), or placebo for six months. Cardiovascular responsiveness was comprehensively assessed with controlled and deep breathing, active orthostatic test, Valsalva maneuver and handgrip test. Hot flushes were accompanied with a significant reduction (-2.2±0.7 vs. 1.3±1.1 beats/min, p=0.03) in resting heart rate during estradiol-only treatment; the route of estradiol administration was no factor in this regard. This effect was attenuated by the addition of MPA to oral estradiol. Hot flushes were also associated with reduced maximal heart rate in response to handgrip during the use of estradiol-only therapy (-2.2±1.3 vs. 2.8±1.5 beats/min, p=0.038); again, the MPA addition eliminated this effect. Hot flushes were accompanied with lowered resting but augmented blood pressure responses to handgrip test during all hormone regimens, whereas in women without hot flushes estradiol-only regimen tended to elevate diastolic resting blood pressure. Hot flushes appear as determinants for cardiovascular responses to hormone therapy. Estradiol-only therapy causes beneficial changes in cardiovascular regulation in flushing women, and these are blunted, in part, by the addition of MPA. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Cardiovascular Responses Associated with the Moving Beans Task: Influence of Psychological Characteristics.

    PubMed

    Iokawa, Kazuaki; Munakata, Masanori; Hattori, Tomomi; Saiki, Shuko; Sone, Toshimasa; Kohzuki, Masahiro

    2017-09-01

    High blood pressure (BP) after stroke is associated with a poor outcome. However, exercise training or speech therapy for patients with stroke can raise the BP. The aim of this study was to examine cardiovascular responses during the moving beans task (MBT) used in occupational therapy and to study the influence of psychological characteristics on cardiovascular responses during this task in healthy subjects. In 34 healthy volunteers, the BP and the heart rate (HR) were continuously measured during the baseline period, the 5-minute MBT, and the 1-minute cold pressor test (CPT). All subjects completed self-reported questionnaires, including the Center for Epidemiologic Studies Depression Scale (CES-D), the State Trait Anxiety Inventory Y-2, and the Japanese version of the 20-item Toronto Alexithymia Scale (TAS-20). The systolic blood pressure (SBP), the diastolic blood pressure (DBP), and the mean blood pressure (MBP) significantly increased during the MBT and the CPT compared with the baseline values. SBP, DBP, and MBP responses during the MBT significantly correlated with the TAS-20 scores. Moreover, DBP response during the MBT correlated with the CES-D scores. The MBT significantly raised BP without increasing the HR. BP responses during this task were influenced by the psychological characteristics of depression and alexithymia. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  4. Effect of an extruded pea or rice diet on postprandial insulin and cardiovascular responses in dogs.

    PubMed

    Adolphe, J L; Drew, M D; Silver, T I; Fouhse, J; Childs, H; Weber, L P

    2015-08-01

    Peas are increasing in popularity as a source of carbohydrate, protein and fibre in extruded canine diets. The aim of this study was to test the health effects of two canine diets with identical macronutrient profiles, but containing either yellow field peas or white rice as the carbohydrate source on metabolism, cardiovascular outcomes and adiposity. First, the acute glycemic, insulinemic and cardiovascular responses to the pea- or rice-based diets were determined in normal weight beagles (n = 7 dogs). The glycemic index did not differ between the pea diet (56 ± 12) and rice diet (63 ± 9). Next, obese beagles (n = 9) were fed the yellow field pea diet or white rice diet ad libitum for 12 weeks in a crossover study. Adiposity (measured using computed tomography), metabolic (oral glucose tolerance test, plasma leptin, adiponectin, C-reactive protein) and cardiovascular assessments (echocardiography and blood pressure) were performed before and after each crossover study period. After 12 weeks on each diet, peak insulin (p = 0.05) and area under the curve (AUC) for insulin after a 10 g oral glucose tolerance test (p = 0.05) were lower with the pea than the rice diet. Diet did not show a significant effect on body weight, fat distribution, cardiovascular variables, adiponectin or leptin. In conclusion, a diet containing yellow field peas reduced the postprandial insulin response after glucose challenge in dogs despite continued obesity, indicating improved metabolic health. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  5. Simulation of hemodynamic responses to the valsalva maneuver: an integrative computational model of the cardiovascular system and the autonomic nervous system.

    PubMed

    Liang, Fuyou; Liu, Hao

    2006-02-01

    The Valsalva maneuver is a frequently used physiological test in evaluating the cardiovascular autonomic functions in human. Although a large pool of experimental data has provided substantial insights into different aspects of the mechanisms underlying the cardiovascular regulations during the Valsalva maneuver, so far a complete comprehension of these mechanisms and the interactions among them is unavailable. In the present study, a computational model of the cardiovascular system (CVS) and its interaction with the autonomic nervous system (ANS) was developed for the purpose of quantifying the individual roles of the CVS and the ANS in the hemodynamic regulations during the Valsalva maneuver. A detailed computational compartmental parameter model of the global CVS, a system of mathematical equations representing the autonomic nervous reflex regulatory functions, and an empirical cerebral autoregulation (CA) model formed the main body of the present model. Based on simulations of the Valsalva maneuvers at several typical postures, it was demonstrated that hemodynamic responses to the maneuver were not only determined by the ANS-mediated cardiovascular regulations, but also significantly affected by the postural-change-induced hemodynamic alterations preceding the maneuver. Moreover, the large-magnitude overshoot in cerebral perfusion immediately after the Valsalva maneuver was found to result from a combined effect of the circulatory autonomic functions, the CA, and the cerebral venous blood pressure.

  6. Prelimbic cortex GABAA receptors are involved in the mediation of restraint stress-evoked cardiovascular responses.

    PubMed

    Fassini, Aline; Resstel, Leonardo B M; Corrêa, Fernando M A

    2016-11-01

    Stress is a response of the organism to homeostasis-threatening stimuli and is coordinated by two main neural systems: the hypothalamic-pituitary-adrenal and the autonomic nervous system. Acute restraint stress (RS) is a model of unavoidable stress, which is characterized by autonomic responses including an increase in mean arterial pressure (MAP) and heart rate (HR), as well as a drop in tail temperature. The prelimbic cortex (PL) has been implicated in the modulation of functional responses caused by RS. The present study aimed to evaluate the role of PL GABAergic neurotransmission in the modulation of autonomic changes induced by RS. Bilateral microinjection of the GABAA receptor antagonist bicuculline methiodide into the PL reduced pressor and tachycardic responses evoked by RS, in a dose-dependent manner, without affecting the tail temperature drop evoked by RS. In order to investigate which peripheral autonomic effector modulated the reduction in RS-cardiovascular responses caused by the blockade of PL GABAA receptors, rats were intravenously pretreated with either atenolol or homatropine methylbromide. The blockade of the cardiac sympathetic nervous system with atenolol blunted the reducing effect of PL treatment with bicuculline methiodide on RS-evoked pressor and tachycardic responses. The blockade of the parasympathetic nervous system with homatropine methylbromide, regardless of affecting the beginning of the tachycardic response, did not impact on the reduction of RS-evoked tachycardic and pressor responses caused by the PL treatment with bicuculline methiodide. The present results indicate that both cardiac sympathetic and parasympathetic activities are involved in the reduction of RS-evoked cardiovascular responses evidenced after the blockade of PL GABAA receptors by bicuculline methiodide.

  7. Fine Ambient Air Particulate Matter Exposure Induces Molecular Alterations Indicative of Cardiovascular Disease Progression in Atherosclerotic Susceptible Mice -- B

    EPA Science Inventory

    Background: Epidemiology studies have reported associations between increased mortality and morbidity with exposure to particulate air pollution, particularly within individuals with pre-existing cardiovascular disease (CVD). Clinical and toxicological studies have provided evide...

  8. Fine Ambient Air Particulate Matter Exposure Induces Molecular Alterations Indicative of Cardiovascular Disease Progression in Atherosclerotic Susceptible Mice -- B

    EPA Science Inventory

    Background: Epidemiology studies have reported associations between increased mortality and morbidity with exposure to particulate air pollution, particularly within individuals with pre-existing cardiovascular disease (CVD). Clinical and toxicological studies have provided evide...

  9. Flying experience and cardiovascular response to rapid head-up tilt in fighter pilots.

    PubMed

    Newman, David G; Callister, Robin

    2009-08-01

    Fighter pilots report G tolerance increases with regular exposure. Our previous work has shown that the cardiovascular system of +Gz-adapted fighter pilots responds differently to orthostatic challenges than that of non-pilots. A +Gz training effect in pilots after repetitive +Gz exposure has also been shown. Individual pilot factors such as flying experience may have a role in +Gz adaptation. In this study, we investigated the relationship between flying hours (a marker of cumulative +Gz exposure) and mean arterial blood pressure (MAP) response to head-up tilt (HUT; a marker of enhanced cardiovascular performance). There were 14 male fighter pilots who participated: 9 had over 1000 h jet flying experience and 5 had less than 500 h. Subjects underwent rapid (approximately 4 s) +75 degrees HUT. Beat-to-beat MAP was measured noninvasively. For each subject, change in MAP from resting values was obtained for the first 30 heart beats of the HUT period. MAP responses to tilt were compared between the experienced and less experienced pilots, and the averages of the MAP deviation values were plotted against flying hours. There was a strong correlation (r = 0.87, P < 0.01) between the MAP response to tilt and jet flying hours. Comparison of the MAP responses to tilt indicates that the experienced pilots increased MAP more (+8 +/- 1.7 vs 5 +/- 1.5 mmHg) and maintained MAP at a higher level during the HUT than the less experienced pilots. The results suggest that flying experience in the high +Gz environment is strongly correlated with enhanced cardiovascular performance under conditions of accelerative stress.

  10. System response time and method of pay: cardiovascular stress effects in computer-based tasks.

    PubMed

    Schleifer, L M; Okogbaa, O G

    1990-12-01

    Psychophysiological effects of computer system response time (slow vs. rapid) and method of pay (incentive vs. nonincentive) were assessed in a computer-based data entry task among forty-five professional typists. Cardiovascular responses (i.e., heart rate and blood pressure) were monitored on a regular basis over four consecutive workdays. Heart rate and blood pressure did not vary significantly with slow or rapid response times. Incentive pay, however, significantly increased blood pressure and decreased heart rate variability across the workdays compared to nonincentive pay. Irrespective of response time or method of pay, performance of the data entry task for sustained periods of time was associated with reduced heart rate and increased heart rate variability. This temporal effect was indicative of reduced effort or increased mental fatigue. The results of this study suggest that incentive pay programmes in data entry work may produce stress-related physiological reactivity among healthy workers.

  11. Cardiovascular responses to postural changes: differences with age for women and men

    NASA Technical Reports Server (NTRS)

    Frey, M. A.; Tomaselli, C. M.; Hoffler, W. G.

    1994-01-01

    The cardiovascular responses to postural change, and how they are affected by aging, are inadequately described in women. Therefore, the authors examined the influence of age and sex on the responses of blood pressure, cardiac output, heart rate, and other variables to change in posture. Measurements were made after 10 minutes each in the supine, seated, and standing positions in 22 men and 25 women who ranged in age from 21 to 59 years. Several variables differed, both by sex and by age, when subjects were supine. On rising, subjects' diastolic and mean arterial pressures, heart rate, total peripheral resistance (TPR), and thoracic impedance increased; cardiac output, stroke volume, and mean stroke ejection rate decreased; and changes in all variables, except heart rate, were greater from supine to sitting than sitting to standing. The increase in heart rate was greater in the younger subjects, and increases in TPR and thoracic impedance were greater in the older subjects. Stroke volume decreased less, and TPR and thoracic impedance increased more, in the women than in the men. The increase in TPR was particularly pronounced in the older women. These studies show that the cardiovascular responses to standing differ, in some respects, between the sexes and with age. The authors suggest that the sex differences are, in part, related to greater decrease of thoracic blood volume with standing in women than in men, and that the age differences result, in part, from decreased responsiveness of the high-pressure baroreceptor system.

  12. Cardiovascular responses to graded degrees of hypoxaemia in the llama fetus.

    PubMed

    Llanos, A J; Riquelme, R A; Moraga, F A; Cabello, G; Parer, J T

    1995-01-01

    The fetal llama exposed to an intense degree of hypoxaemia did not increase cerebral blood flow, but showed a marked peripheral vasoconstriction. The same cardiovascular response is observed in fetal sheep submitted to a extremely severe hypoxaemia, when the initial compensatory vasodilatory mechanisms in brain and heart fail. To investigate whether the fetal llama responses to acute hypoxaemia are adaptive, or whether they are the result of a breakdown of mechanisms of blood flow redistribution that favours the central nervous system, we studied seven fetal llamas (0.6-0.7 of gestation) chronically-catheterized during 1 h of graded and progressive hypoxaemia. Fetal ascending aorta blood gases and fetal cardiac output and its distribution (radiolabelled-microspheres) were measured after 60 min of normoxaemia (B) and at the end of 20 min (H20), 40 min (H40) and 60 min (H60) of hypoxaemia. Data were analysed by ANOVA and Newman-Keuls tests. Each treatment resulted in a lower (P < 0.05) percentage of haemoglobin saturation than hypoxaemia; H40 was lower than H20, and H60 was lower than H20 and H40. No statistical difference was observed among treatments for cardiac output or cerebral blood flow. These results demonstrate that fetal cardiac output and brain blood flow are maintained at all degrees of hypoxaemia, indicating that these cardiovascular responses are an adaptive response in the llama fetus, rather than an index of cardiorespiratory decompensation.

  13. Rat Cardiovascular Responses to Whole Body Suspension: Head-down and Non-Head-Down Tilt

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, Joseph M.; Dombrowski, Judy

    1992-01-01

    The rat whole body suspension technique mimics responses seen during exposure to microgravity and was evaluated as a model for cardiovascular responses with two series of experiments. In one series, changes were monitored in chronically catheterized rats during 7 days of Head-Down Tilt (HDT) or Non-Head-Down Tilt (N-HDT) and after several hours of recovery. Elevations of mean arterial (MAP), systolic, and diastolic pressures of approx. 20 % (P less than 0.05) in HDT rats began as early as day 1 and were maintained for the duration of suspension. Pulse pressures were relatively unaffected, but heart rates were elevated approx. 10 %. During postsuspension (2-7 h), most cardiovascular parameters returned to presuspension levels. N-HDT rats exhibited elevations chiefly on days 3 and 7. In the second series, blood pressure was monitored in 1- and 3-day HDT and N-HDT rats to evaluate responses to rapid head-up tilt. MAP, systolic and diastolic pressures, and HR were elevated (P less than 0.05) in HDT and N-HDT rats during head-up tilt after 1 day of suspension, while pulse pressures remained un changed. HDT rats exhibited elevated pretilt MAP and failed to respond to rapid head-up tilt with further increase of MAP on day 3, indicating some degree of deconditioning. The whole body suspended rat may be useful as a model to better understand responses of rats exposed to microgravity.

  14. Halothane concentrations required to block the cardiovascular responses to incision (MAC CVR) in infants and children.

    PubMed

    Ishizawa, Y; Dohi, S

    1993-01-01

    The purpose of this study was to determine the halothane concentration in N2O required to block the cardiovascular responses to skin incision (MAC CVR) in infants and children. We studied 64 unpremedicated ASA 1 infants and children (one month to seven years). In each infant or child, anaesthesia was induced slowly with halothane and N2O, and an endotracheal tube was placed. The MAC CVR was assessed, after a steady state end-tidal halothane concentration had been established for ten minutes, by the "up and down technique" of Dixon. Positive responses were defined as an increase in MAP or HR > 10%. The MAC CVR50 values of halothane with 60% N2O were 1.16 +/- 0.23% at 1-6 mo, 1.17 +/- 0.18% at 7-12 mo, 0.95 +/- 0.26% at 1-3 yr, and 1.12 +/- 0.16% at 4-7 yr. The value at 1-3 years children was less than those in the other age groups (P < 0.05). The changes of MAP were correlated with changes of both HR and pupillary diameter. These results indicate that the values of MAC CVR50 of halothane in infants and children are higher than those required to block motor responses (MAC). The halothane requirement to block cardiovascular responses is lowest in the children aged one to three years.

  15. Methods for study of cardiovascular adaptation of small laboratory animals during exposure to altered gravity. [hypothermia for cardiovascular control and cancer therapy

    NASA Technical Reports Server (NTRS)

    Popovic, V.

    1973-01-01

    Several new techniques are reported for studying cardiovascular circulation in small laboratory animals kept in metabolic chambers. Chronical cannulation, miniaturized membrane type heart-lung machines, a prototype walking chamber, and a fluorocarbon immersion method to simulate weightlessness are outlined. Differential hypothermia work on rat cancers provides localized embedding of radionuclides and other chemotherapeutical agents in tumors and increases at the same time blood circulation through the warmed tumor as compared to the rest of the cold body. Some successful clinical applications of combined chemotherapy and differential hypothermia in skin cancer, mammary tumors, and brain gliomas are described.

  16. Methods for study of cardiovascular adaptation of small laboratory animals during exposure to altered gravity. [hypothermia for cardiovascular control and cancer therapy

    NASA Technical Reports Server (NTRS)

    Popovic, V.

    1973-01-01

    Several new techniques are reported for studying cardiovascular circulation in small laboratory animals kept in metabolic chambers. Chronical cannulation, miniaturized membrane type heart-lung machines, a prototype walking chamber, and a fluorocarbon immersion method to simulate weightlessness are outlined. Differential hypothermia work on rat cancers provides localized embedding of radionuclides and other chemotherapeutical agents in tumors and increases at the same time blood circulation through the warmed tumor as compared to the rest of the cold body. Some successful clinical applications of combined chemotherapy and differential hypothermia in skin cancer, mammary tumors, and brain gliomas are described.

  17. Cardiovascular alterations at different stages of hypertension development during ethanol consumption: Time-course of vascular and autonomic changes

    SciTech Connect

    Crestani, Carlos C.; Lopes da Silva, Andréia; Scopinho, América A.; Ruginsk, Silvia G.; Uchoa, Ernane T.; Correa, Fernando M.A.; Elias, Lucila L.K.; Antunes-Rodrigues, José; Resstel, Leonardo B.M.

    2014-10-15

    The aim of the present work was to establish a time-course correlation between vascular and autonomic changes that contribute to the development of hypertension during ethanol ingestion in rats. For this, male Wistar rats were subjected to the intake of increasing ethanol concentrations in their drinking water during four weeks. Ethanol effects were investigated at the end of each week. Mild hypertension was already observed at the first week of treatment, and a progressive blood pressure increase was observed along the evaluation period. Increased pressor response to phenylephrine was observed from first to fourth week. α{sub 1}-adrenoceptor protein in the mesenteric bed was enhanced at the first week, whereas β{sub 2}-adrenoceptor protein in the aorta was reduced after the second week. In the third week, ethanol intake facilitated the depressor response to sodium nitroprusside, whereas in the fourth week it reduced nitrate content in aorta and increased it plasma. The bradycardic component of the baroreflex was impaired, whereas baroreflex tachycardia was enhanced at the third and fourth weeks. AT{sub 1A} receptor and C-type natriuretic peptide (CNP) mRNAs in the nucleus tractus solitarius were increased at the fourth week. These findings suggest that increased vascular responsiveness to vasoconstrictor agents is possibly a link factor in the development and maintenance of the progressive hypertension induced by ethanol consumption. Additionally, baroreflex changes are possibly mediated by alterations in angiotensinergic mechanisms and CNP content within the brainstem, which contribute to maintaining the hypertensive state in later phases of ethanol ingestion. Facilitated vascular responsiveness to nitric oxide seems to counteract ethanol-induced hypertension. - Highlights: • Mild hypertension was observed during the entire period of ethanol ingestion. • Ethanol facilitated vascular reactivity to vasoactive agents. • Changes in baroreflex activity

  18. The prelimbic cortex muscarinic M₃ receptor-nitric oxide-guanylyl cyclase pathway modulates cardiovascular responses in rats.

    PubMed

    Fassini, Aline; Antero, Leandro S; Corrêa, Fernando M A; Joca, Sâmia R; Resstel, Leonardo B M

    2015-05-01

    The prelimbic cortex (PL), a limbic structure, sends projections to areas involved in the control of cardiovascular responses. Stimulation of the PL with acetylcholine (ACh) evokes depressor and tachycardiac responses mediated by local PL muscarinic receptors. Early studies demonstrated that stimulation of muscarinic receptors induced nitric oxide (NO) synthesis and cyclic guanosine cyclic monophosphate (cGMP) formation. Hence, this study investigates which PL muscarinic receptor subtype is involved in the cardiovascular response induced by ACh and tests the hypothesis that cardiovascular responses caused by muscarinic receptor stimulation in the PL are mediated by local NO and cGMP formation. PL pretreatment with J104129 (an M3 receptor antagonist) blocked the depressor and tachycardiac response evoked by injection of ACh into the PL. Pretreatment with either pirenzepine (an M1 receptor antagonist) or AF-DX 116 (an M2 and M4 receptor antagonist) did not affect cardiovascular responses evoked by ACh. Moreover, similarly to the antagonism of PL M3 receptors, pretreatment with N(ω)-propyl-L-arginine (an inhibitor of neuronal NO synthase), carboxy-PTIO(S)-3-carboxy-4-hydroxyphenylglicine (an NO scavenger), or 1H-[1,2,4]oxadiazolol-[4,3-a]quinoxalin-1-one (a guanylate cyclase inhibitor) blocked both the depressor and the tachycardiac response evoked by ACh. The current results demonstrate that cardiovascular responses evoked by microinjection of ACh into the PL are mediated by local activation of the M3 receptor-NO-guanylate cyclase pathway.

  19. Effects of inducible nitric oxide synthase blockade within the periaqueductal gray on cardiovascular responses during mechanical, heat, and cold nociception.

    PubMed

    Chaitoff, Kevin A; Toner, Francis; Tedesco, Anthony; Maher, Timothy J; Ally, Ahmmed

    2012-02-01

    We have examined the role of inducible nitric oxide synthase (iNOS) within the dorsolateral periaqueductal gray mater (dlPAG) on cardiovascular responses during mechanical, thermal, and cold nociception in anesthetized rats. Mechanical stimulus was applied by a unilateral hindpaw pinch for 10 s that increased mean arterial pressure (MAP) and heart rate (HR). Bilateral microdialysis of a selective iNOS inhibitor, aminoguanidine (AGN; 10 μM), into the dlPAG for 30 min augmented MAP and HR responses during a mechanical stimulation. The cardiovascular responses recovered following discontinuation of the drug. Heat stimulus was generated by immersing one hindpaw metatarsus in a water bath at 52°C for 10 s, and this increased MAP and HR. Administration of AGN into the PAG potentiated these cardiovascular responses. Cardiovascular responses recovered following discontinuation of the drug. In contrast, application of a cold stimulus by immersing one hindpaw at 10°C for 10 s resulted in depressor and bradycardic responses. A second cold stimulus resulted in a response that was not significantly different from that prior to or after recovery from the AGN infusion. These results demonstrate that iNOS within the dlPAG plays a differential role in modulating cardiovascular responses during mechanical-, heat-, and cold-mediated nociception.

  20. Neuropeptides in the posterodorsal medial amygdala modulate central cardiovascular reflex responses in awake male rats

    PubMed Central

    Quagliotto, E.; Casali, K.R.; Dal Lago, P.; Rasia-Filho, A.A.

    2014-01-01

    The rat posterodorsal medial amygdala (MePD) links emotionally charged sensory stimuli to social behavior, and is part of the supramedullary control of the cardiovascular system. We studied the effects of microinjections of neuroactive peptides markedly found in the MePD, namely oxytocin (OT, 10 ng and 25 pg; n=6/group), somatostatin (SST, 1 and 0.05 μM; n=8 and 5, respectively), and angiotensin II (Ang II, 50 pmol and 50 fmol; n=7/group), on basal cardiovascular activity and on baroreflex- and chemoreflex-mediated responses in awake adult male rats. Power spectral and symbolic analyses were applied to pulse interval and systolic arterial pressure series to identify centrally mediated sympathetic/parasympathetic components in the heart rate variability (HRV) and arterial pressure variability (APV). No microinjected substance affected basal parameters. On the other hand, compared with the control data (saline, 0.3 µL; n=7), OT (10 ng) decreased mean AP (MAP50) after baroreflex stimulation and increased both the mean AP response after chemoreflex activation and the high-frequency component of the HRV. OT (25 pg) increased overall HRV but did not affect any parameter of the symbolic analysis. SST (1 μM) decreased MAP50, and SST (0.05 μM) enhanced the sympathovagal cardiac index. Both doses of SST increased HRV and its low-frequency component. Ang II (50 pmol) increased HRV and reduced the two unlike variations pattern of the symbolic analysis (P<0.05 in all cases). These results demonstrate neuropeptidergic actions in the MePD for both the increase in the range of the cardiovascular reflex responses and the involvement of the central sympathetic and parasympathetic systems on HRV and APV. PMID:25424367

  1. The significance of hypertensive response to exercise as a predictor of hypertension and cardiovascular disease.

    PubMed

    Sharabi, Y; Ben-Cnaan, R; Hanin, A; Martonovitch, G; Grossman, E

    2001-05-01

    Several studies have shown that exaggerated blood pressure (BP) response to exercise can predict the development of hypertension and target organ damage, but others did not. The aim of this study was to evaluate the relationship between exaggerated BP response to exercise (ExBPR) and the development of hypertension or cardiovascular disease. We reviewed the charts of male subjects who, during the years 1991-1994, had a routine check up that included an exercise stress-test. For each subject, the following parameters were noted: age; body mass index (BMI); history of diabetes; cigarette smoking; family history of ischaemic heart disease and lipid profile. BP and heart rate at rest and during exercise were recorded as well. ExBPR was defined whenever peak exercise systolic BP or diastolic BP was over 200 mm Hg or 100 mm Hg respectively. We identified 73 males who exhibited ExBPR and matched them with a control group of 117 subjects with similar age who had a normal BP response. The mean age of the studied group was 42.6 years and the average follow-up was 5.7 years. Baseline characteristics were similar in both groups. During the follow-up we observed hypertension among 22% in those with ExBPR in contrast to 2.6% in the control group (P < 0.0001). In addition, more subjects of the ExBPR group required cardiovascular medications than of those in the control group (19.2% vs 4.3%, P = 0.0008). Thus, it seems that ExBPR predicts the development of hypertension and cardiovascular diseases. We therefore suggest that subjects with ExBPR should be followed more closely and be instructed for lifestyle modifications which may delay the development of such diseases.

  2. Neuropeptides in the posterodorsal medial amygdala modulate central cardiovascular reflex responses in awake male rats.

    PubMed

    Quagliotto, E; Casali, K R; Dal Lago, P; Rasia-Filho, A A

    2015-02-01

    The rat posterodorsal medial amygdala (MePD) links emotionally charged sensory stimuli to social behavior, and is part of the supramedullary control of the cardiovascular system. We studied the effects of microinjections of neuroactive peptides markedly found in the MePD, namely oxytocin (OT, 10 ng and 25 pg; n=6/group), somatostatin (SST, 1 and 0.05 μM; n=8 and 5, respectively), and angiotensin II (Ang II, 50 pmol and 50 fmol; n=7/group), on basal cardiovascular activity and on baroreflex- and chemoreflex-mediated responses in awake adult male rats. Power spectral and symbolic analyses were applied to pulse interval and systolic arterial pressure series to identify centrally mediated sympathetic/parasympathetic components in the heart rate variability (HRV) and arterial pressure variability (APV). No microinjected substance affected basal parameters. On the other hand, compared with the control data (saline, 0.3 µL; n=7), OT (10 ng) decreased mean AP (MAP50) after baroreflex stimulation and increased both the mean AP response after chemoreflex activation and the high-frequency component of the HRV. OT (25 pg) increased overall HRV but did not affect any parameter of the symbolic analysis. SST (1 μM) decreased MAP50, and SST (0.05 μM) enhanced the sympathovagal cardiac index. Both doses of SST increased HRV and its low-frequency component. Ang II (50 pmol) increased HRV and reduced the two unlike variations pattern of the symbolic analysis (P<0.05 in all cases). These results demonstrate neuropeptidergic actions in the MePD for both the increase in the range of the cardiovascular reflex responses and the involvement of the central sympathetic and parasympathetic systems on HRV and APV.

  3. Changing CS Features Alters Evaluative Responses in Evaluative Conditioning

    ERIC Educational Resources Information Center

    Unkelbach, Christian; Stahl, Christoph; Forderer, Sabine

    2012-01-01

    Evaluative conditioning (EC) refers to changes in people's evaluative responses toward initially neutral stimuli (CSs) by mere spatial and temporal contiguity with other positive or negative stimuli (USs). We investigate whether changing CS features from conditioning to evaluation also changes people's evaluative response toward these CSs. We used…

  4. Changing CS Features Alters Evaluative Responses in Evaluative Conditioning

    ERIC Educational Resources Information Center

    Unkelbach, Christian; Stahl, Christoph; Forderer, Sabine

    2012-01-01

    Evaluative conditioning (EC) refers to changes in people's evaluative responses toward initially neutral stimuli (CSs) by mere spatial and temporal contiguity with other positive or negative stimuli (USs). We investigate whether changing CS features from conditioning to evaluation also changes people's evaluative response toward these CSs. We used…

  5. The prodromal phase of obesity-related chronic kidney disease: early alterations in cardiovascular and renal function in obese children and adolescents.

    PubMed

    Doyon, Anke; Schaefer, Franz

    2013-11-01

    Childhood overweight and obesity is a relevant health condition with multi-organ involvement. Obesity shows significant tracking into adult life and is associated with an increased risk of serious adverse health outcomes both during childhood and later adulthood. The classical sequelae of obesity such as hypertension, metabolic syndrome and inflammation do develop at a paediatric age. Cardiovascular consequences, such as increased carotid intima-media thickness, and left ventricular hypertrophy, as well as functional alterations of the heart and arteries, are commonly traceable at an early age. Renal involvement can occur at a young age and is associated with a high probability of progressive chronic kidney disease. There is solid evidence suggesting that consequent treatment including both lifestyle changes and pharmacological therapy can reduce cardiovascular, metabolic and renal risks in obese children and adolescents.

  6. Effects of whole-body cryotherapy duration on thermal and cardio-vascular response.

    PubMed

    Fonda, Borut; De Nardi, Massimo; Sarabon, Nejc

    2014-05-01

    Whole-body cryotherapy (WBC) is the exposure of minimally dressed participants to very cold air, either in a specially designed chamber (cryo-chamber) or cabin (cryo-cabin), for a short period of time. Practitioners are vague when it comes to recommendations on the duration of a single session. Recommended exposure for cryo-chamber is 150s, but no empirically based recommendations are available for a cryo-cabin. Therefore the aim of this study was to examine thermal and cardio-vascular responses after 90, 120, 150 and 180s of WBC in a cryo-cabin. Our hypothesis was that skin temperature would be significantly lower after longer exposers. Twelve male participants (age 23.9±4.2 years) completed four WBC of different durations (90, 120, 150 and 180s) in a cryo-cabin. Thermal response, heart rate and blood pressure were measured prior, immediately after, 5min after and 30min after the session. Skin temperature differed significantly among different durations, except between 150 and 180s. There was no significant difference in heart rate and blood pressure. Thermal discomfort during a single session displayed a linear increase throughout the whole session. Our results indicate that practitioners and clinicians using cryo-cabin for WBC do not need to perform sessions longer than 150s. We have shown that longer sessions do not substantially affect thermal and cardio-vascular response, but do increase thermal discomfort.

  7. Baseline values of cardiovascular and respiratory parameters predict response to acute hypoxia in young healthy men.

    PubMed

    Melnikov, V N; Krivoschekov, S G; Divert, V E; Komlyagina, T G; Consedine, N S

    2017-02-28

    The majority of the available works have studied distinct hypoxic responses of respiratory and cardiovascular systems. This study examines how these systems interact while responding to hypoxia and whether baseline metrics moderate reactions to a hypoxic challenge. Central hemodynamic, aortic wave reflection, and gas exchange parameters were measured in 27 trained young men before and after 10-min normobaric isocapnic hypoxia (10 % O2). Associations were assessed by correlation and multiple regression analyses. Hypoxic changes in the parameters of pulse wave analysis such as augmentation index (-114 %, p=0.007), pulse pressure amplification (+6 %, p=0.020), time to aortic reflection wave (+21 %, p<0.001) report on the increase in arterial distensibility. Specifically, initially compliant arteries blunt the positive cardiac chronotropic response to hypoxia and facilitate the myocardial workload. The degree of blood oxygen desaturation is directly correlated with both baseline values and hypoxic responses of aortic and peripheral blood pressures. The hypoxia-induced gain in ventilation (VE), while controlling for basal VE and heart rate (HR), is inversely associated with deltaHR and deltasystolic blood pressure. The study suggests that cardiovascular and respiratory systems mutually supplement each other when responding to hypoxic challenge.

  8. Mechanisms underlying the sympathomimetic cardiovascular responses elicited by gamma-hydroxybutyrate.

    PubMed

    Hicks, Alissa R; Kapusta, Daniel R; Varner, Kurt J

    2004-12-01

    Gamma-hydroxybutyrate (GHB) is generally thought to be a central nervous system depressant; however, GHB also has sympathomimetic cardiovascular actions. Radio telemetry was used to record the cardiovascular responses elicited by GHB (180-1000 mg/kg IV) in conscious rats. GHB elicited increases in mean arterial pressure (MAP) (24 +/- 3 to 60 +/- 5 mm Hg) lasting from 28 +/- 8 to 227 +/- 37 minutes. GHB (560 and 1000 mg/kg IV) also elicited a prolonged tachycardic response (85 +/- 23 and 95 +/- 22 bpm). The hypertension and tachycardia elicited by GHB (560 mg/kg) were reversed by the intravenous and intracerebroventricular administration of the GABAb receptor antagonist CGP 35348. CGP 35348 also reversed GHB-mediated increases in renal sympathetic nerve activity (RSNA). Administration of the purported GHB receptor antagonist NCS-382 reversed the increase in heart rate but not the pressor response elicited by GHB in telemetered rats. These data indicate that the intravenous administration of GHB markedly increases MAP, heart rate, and RSNA in conscious rats via activation of central GABAb receptors. In addition, GHB receptors appear to selectively mediate the increase in heart rate elicited by large doses of GHB.

  9. Concord Grape Juice Polyphenols and Cardiovascular Risk Factors: Dose-Response Relationships

    PubMed Central

    Blumberg, Jeffrey B.; Vita, Joseph A.; Chen, C. -Y. Oliver

    2015-01-01

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship of fruit juice flavonoids to these outcomes. Utilizing the results of clinical trials testing single doses, we have analyzed data from studies of 100% Concord grape juice by placing its flavonoid content in the context of results from randomized clinical trials of other polyphenol-rich foods and beverages describing the same outcomes but covering a broader range of intake. We selected established biomarkers determined by similar methods for measuring flow-mediated vasodilation (FMD), blood pressure, platelet aggregation, and the resistance of low density lipoprotein cholesterol (LDL) to oxidation. Despite differences among the clinical trials in the treatment, subjects, and duration, correlations were observed between the dose and FMD. Inverse dose-response relationships, albeit with lower correlation coefficients, were also noted for the other outcomes. These results suggest a clear relationship between consumption of even modest serving sizes of Concord grape juice, flavonoid intake, and effects on risk factors for cardiovascular disease. This approach to dose-response relationships may prove useful for testing other individual foods and beverages. PMID:26633488

  10. Rat cardiovascular responses to whole body suspension - Head-down and non-head-down tilt

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, Joseph M.; Dombrowski, Judy

    1992-01-01

    Two experiments aimed at examining the versatility of the whole body suspension (WBS) system as a ground-based model for cardiovascular effects of microgravity are described. The first experiment studied heart rate and arterial pressure responses in rats during a 7-day period of head-down tilt (HDT) or nonhead-down tilt (NHDT) and after removal from whole body suspension (WBS). Mean arterial (MAP), systolic, and diastolic pressures increased about 20 percent in HDT rats on the fist day, heart rates were elevated about 10 percent. During postsuspension most cardiovascular parameters returned to presuspension levels. The second experiment evaluated responses to rapid head-up tilt in HDT and NHDT rats. It was observed that, while pulse pressures remained unchanged, MAP, systolic and diastolic pressures, and HR were elevated in HDT and NHDT rats during head-up tilt after one day of suspension. The WBS rats are considered to be useful as a model to better understand responses of rats exposed to microgravity.

  11. The absence of cardiovascular and respiratory responses to changes in right ventricular pressure in anaesthetized dogs.

    PubMed Central

    Crisp, A J; Hainsworth, R; Tutt, S M

    1988-01-01

    1. This study was undertaken to determine whether physiological changes in pressure localized to the right ventricle result in reflex cardiovascular or respiratory responses. 2. Right ventricular systolic pressure was changed using a preparation in which right atrial and carotid sinus pressures were held constant. The pulmonary and hence the systemic circulation were perfused at constant flow. Vascular resistance and respiratory activity were assessed from the systemic arterial pressure and the phrenic electroneurogram. 3. Changes in right ventricular systolic pressure did not result in any consistent changes in heart rate, systemic arterial blood pressure or phrenic nerve activity. 4. Expected responses occurred to changes in the stimuli to carotid baroreceptors and chemoreceptors, distension of pulmonary arterial baroreceptors, and injections of veratridine into the left ventricle and pulmonary circulation. This suggests that the absence of responses to right ventricular distension was unlikely to have been due to damage to nervous pathways. 5. These results indicate that it is unlikely that there are reflexes arising from the right ventricle which have a major role in cardiovascular or respiratory control. PMID:3256611

  12. Concord Grape Juice Polyphenols and Cardiovascular Risk Factors: Dose-Response Relationships.

    PubMed

    Blumberg, Jeffrey B; Vita, Joseph A; Chen, C-Y Oliver

    2015-12-02

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship of fruit juice flavonoids to these outcomes. Utilizing the results of clinical trials testing single doses, we have analyzed data from studies of 100% Concord grape juice by placing its flavonoid content in the context of results from randomized clinical trials of other polyphenol-rich foods and beverages describing the same outcomes but covering a broader range of intake. We selected established biomarkers determined by similar methods for measuring flow-mediated vasodilation (FMD), blood pressure, platelet aggregation, and the resistance of low density lipoprotein cholesterol (LDL) to oxidation. Despite differences among the clinical trials in the treatment, subjects, and duration, correlations were observed between the dose and FMD. Inverse dose-response relationships, albeit with lower correlation coefficients, were also noted for the other outcomes. These results suggest a clear relationship between consumption of even modest serving sizes of Concord grape juice, flavonoid intake, and effects on risk factors for cardiovascular disease. This approach to dose-response relationships may prove useful for testing other individual foods and beverages.

  13. Hypoalgesia and altered inflammatory responses in mice lacking kinin B1 receptors.

    PubMed

    Pesquero, J B; Araujo, R C; Heppenstall, P A; Stucky, C L; Silva, J A; Walther, T; Oliveira, S M; Pesquero, J L; Paiva, A C; Calixto, J B; Lewin, G R; Bader, M

    2000-07-05

    Kinins are important mediators in cardiovascular homeostasis, inflammation, and nociception. Two kinin receptors have been described, B1 and B2. The B2 receptor is constitutively expressed, and its targeted disruption leads to salt-sensitive hypertension and altered nociception. The B1 receptor is a heptahelical receptor distinct from the B2 receptor in that it is highly inducible by inflammatory mediators such as bacterial lipopolysaccharide and interleukins. To clarify its physiological function, we have generated mice with a targeted deletion of the gene for the B1 receptor. B1 receptor-deficient animals are healthy, fertile, and normotensive. In these mice, bacterial lipopolysaccharide-induced hypotension is blunted, and there is a reduced accumulation of polymorphonuclear leukocytes in inflamed tissue. Moreover, under normal noninflamed conditions, they are analgesic in behavioral tests of chemical and thermal nociception. Using whole-cell patch-clamp recordings, we show that the B1 receptor was not necessary for regulating the noxious heat sensitivity of isolated nociceptors. However, by using an in vitro preparation, we could show that functional B1 receptors are present in the spinal cord, and their activation can facilitate a nociceptive reflex. Furthermore, in B1 receptor-deficient mice, we observed a reduction in the activity-dependent facilitation (wind-up) of a nociceptive spinal reflex. Thus, the kinin B1 receptor plays an essential physiological role in the initiation of inflammatory responses and the modulation of spinal cord plasticity that underlies the central component of pain. The B1 receptor therefore represents a useful pharmacological target especially for the treatment of inflammatory disorders and pain.

  14. Chemosensitivity, Cardiovascular Risk, and the Ventilatory Response to Exercise in COPD.

    PubMed

    Stickland, Michael K; Fuhr, Desi P; Edgell, Heather; Byers, Brad W; Bhutani, Mohit; Wong, Eric Y L; Steinback, Craig D

    2016-01-01

    COPD is associated with elevated cardiovascular risk and a potentiated ventilatory response to exercise. Enhanced carotid chemoreceptor (CC) activity/sensitivity is present in other clinical conditions, has been shown to contribute to sympathetic vasoconstrictor outflow, and is predictive of mortality. CC activity/sensitivity, and the resulting functional significance, has not been well examined in COPD. We hypothesized that CC activity/sensitivity would be elevated in COPD, and related to increased pulse wave velocity (a marker of CV risk) and the ventilatory response to exercise. 30 COPD patients and 10 healthy age-matched controls were examined. Participants performed baseline cardiopulmonary exercise and pulmonary function testing. CC activity was later evaluated by the drop in ventilation with breathing 100% O2, and CC sensitivity was then assessed by the ventilatory response to hypoxia (ΔVE/ΔSpO2). Peripheral arterial stiffness was subsequently evaluated by measurement of pulse wave velocity (PWV) using applanation tonometry while the subjects were breathing room air, and then following chemoreceptor inhibition by breathing 100% O2 for 2 minutes. CC activity, CC sensitivity, PWV and the ventilatory response to exercise were all increased in COPD relative to controls. CC sensitivity was related to PWV; however, neither CC activity nor CC sensitivity was related to the ventilatory response to exercise in COPD. CC inhibition by breathing 100% O2 normalized PWV in COPD, while no effect was observed in controls. CC activity and sensitivity are elevated in COPD, and appear related to cardiovascular risk; however, CC activity/sensitivity does not contribute to the potentiated ventilatory response to exercise.

  15. Chemosensitivity, Cardiovascular Risk, and the Ventilatory Response to Exercise in COPD

    PubMed Central

    Stickland, Michael K.; Fuhr, Desi P.; Edgell, Heather; Byers, Brad W.; Bhutani, Mohit; Wong, Eric Y. L.; Steinback, Craig D.

    2016-01-01

    COPD is associated with elevated cardiovascular risk and a potentiated ventilatory response to exercise. Enhanced carotid chemoreceptor (CC) activity/sensitivity is present in other clinical conditions, has been shown to contribute to sympathetic vasoconstrictor outflow, and is predictive of mortality. CC activity/sensitivity, and the resulting functional significance, has not been well examined in COPD. We hypothesized that CC activity/sensitivity would be elevated in COPD, and related to increased pulse wave velocity (a marker of CV risk) and the ventilatory response to exercise. Methods: 30 COPD patients and 10 healthy age-matched controls were examined. Participants performed baseline cardiopulmonary exercise and pulmonary function testing. CC activity was later evaluated by the drop in ventilation with breathing 100% O2, and CC sensitivity was then assessed by the ventilatory response to hypoxia (ΔVE/ΔSpO2). Peripheral arterial stiffness was subsequently evaluated by measurement of pulse wave velocity (PWV) using applanation tonometry while the subjects were breathing room air, and then following chemoreceptor inhibition by breathing 100% O2 for 2 minutes. Results: CC activity, CC sensitivity, PWV and the ventilatory response to exercise were all increased in COPD relative to controls. CC sensitivity was related to PWV; however, neither CC activity nor CC sensitivity was related to the ventilatory response to exercise in COPD. CC inhibition by breathing 100% O2 normalized PWV in COPD, while no effect was observed in controls. Conclusion: CC activity and sensitivity are elevated in COPD, and appear related to cardiovascular risk; however, CC activity/sensitivity does not contribute to the potentiated ventilatory response to exercise. PMID:27355356

  16. Do Integrins Mediate the Skeletal Response to Altered Loading?

    NASA Technical Reports Server (NTRS)

    vanderMeulen, Marjolein C. H.

    2004-01-01

    In vivo experiments were performed to examine the role of B1 integrin in skeletal adaptation to reduced and increased loading. Transgenic mice were generated with a dominant negative form of the B1 integrin cytoplasmic domain with expression driven by the osteocalcin promoter (pOCb1DN). This fragment consists of the transmembrane and intracellular domains and interferes with endogenous integrin signalling in vitro. This promoter targets expression of the transgene to mature bone cells. Expression of the transgene was confirmed by immunoprecipitation and western blotting. Reduced loading was generated by hindlimb suspension and increased loading the resumption of normal loading following hindlimb suspension. Two groups of female 35-day old mice were examined: poCb1DN transgenic mice (TG) and wild-type littermate controls (WT). Animals were hindlimb suspended for 1 week (HU, n = l0/gp) or 4 weeks (HU, n = 4 - 7/gp) or suspended for 4 weeks followed by reloading by normal ambulation for 4 weeks (RL, n = l0/gp). Age-matched controls (CT) were pairfed based on the HU food intake. The protocols were approved by the NASA Ames Research Center IACUC. Upon completion of the experimental protocol, body mass was recorded and tissues of interest removed and analyzed following standard procedures. Femoral whole bone structural behavior was measured in torsion to failure to obtain whole bone strength (failure torque) and torsional rigidity. Ash content (ash) and fraction (% ash) were determined for the tibia. Total ash is indicative of bone size whereas %ash is a material property. Tibial curvature was measured from microradiographs. For each experiment, the effects of genotype (TG, WT) and treatment (CT, HU/RL) were assessed by two-factor ANOVA followed by the Tukey-Kramer posthoc to identify significant differences at an alpha level of 0.05. Our goal was to understand differences resulting from altered integrin function in the adaptation to altered loading.

  17. Adrenergic and vasopressinergic contributions to the cardiovascular response to acute hypoxaemia in the llama fetus

    PubMed Central

    Giussani, D A; Riquelme, R A; Sanhueza, E M; Hanson, M A; Blanco, C E; Llanos, A J

    1999-01-01

    The effects of fetal intravenous treatment with phentolamine or a vasopressinergic V1-receptor antagonist on the fetal cardiovascular responses to acute hypoxaemia in the llama were investigated. Six llama fetuses were surgically prepared between 60 and 70% of gestation under general halothane anaesthesia with vascular catheters and transit-time ultrasonic flow probes around a carotid artery and a femoral artery. At least 4 days after surgery all fetuses were subjected to a 3 h experiment: 1 h of normoxia, 1 h of hypoxaemia and 1 h of recovery while on slow i.v. infusion with saline. On separate days this experiment was repeated with fetal i.v. treatment with either phentolamine or a V1-receptor antagonist dissolved in saline. During saline infusion all llama fetuses responded to acute hypoxaemia with intense femoral vasoconstriction. Phentolamine during normoxia produced hypotension, tachycardia and vasodilatation in both the carotid and the femoral circulations. During hypoxaemia, fetuses treated with phentolamine did not elicit the pronounced femoral vasoconstriction and all died within 20 min of the onset of hypoxaemia. A V1-receptor antagonist produced a femoral vasodilatation during normoxia but did not affect the fetal cardiovascular responses to acute hypoxaemia. In conclusion, α-adrenergic and V1-vasopressinergic mechanisms contribute to a basal vasoconstrictor tone in the femoral circulation in the llama fetus. The enhanced femoral vasoconstriction during acute hypoxaemia in the llama fetus is not mediated by stimulation of V1-vasopressin receptors, but is dependent on α-adrenergic receptor stimulation. Such α-adrenergic efferent mechanisms are indispensable to fetal survival during hypoxaemia in the llama since their abolition leads to cardiovascular collapse and death. PMID:9925892

  18. Cardiovascular and cerebrovascular effects in response to red bull consumption combined with mental stress.

    PubMed

    Grasser, Erik Konrad; Dulloo, Abdul G; Montani, Jean-Pierre

    2015-01-15

    The sale of energy drinks is often accompanied by a comprehensive and intense marketing with claims of benefits during periods of mental stress. As it has been shown that Red Bull negatively impacts human hemodynamics at rest, we investigated the cardiovascular and cerebrovascular consequences when Red Bull is combined with mental stress. In a randomized cross-over study, 20 young healthy humans ingested either 355 ml of a can Red Bull or water and underwent 80 minutes after the respective drink a mental arithmetic test for 5 minutes. Continuous cardiovascular and cerebrovascular recordings were performed for 20 minutes before and up to 90 minutes after drink ingestion. Measurements included beat-to-beat blood pressure (BP), heart rate, stroke volume, and cerebral blood flow velocity. Red Bull increased systolic BP (+7 mm Hg), diastolic BP (+4 mm Hg), and heart rate (+7 beats/min), whereas water drinking had no significant effects. Cerebral blood flow velocity decreased more in response to Red Bull than to water (-9 vs -3 cm/s, p <0.005). Additional mental stress further increased both systolic BP and diastolic BP (+3 mm Hg, p <0.05) and heart rate (+13 beats/min, p <0.005) in response to Red Bull; similar increases were also observed after water ingestion. In combination, Red Bull and mental stress increased systolic BP by about 10 mm Hg, diastolic BP by 7 mm Hg, and heart rate by 20 beats/min and decreased cerebral blood flow velocity by -7 cm/s. In conclusion, the combination of Red Bull and mental stress impose a cumulative cardiovascular load and reduces cerebral blood flow even under a mental challenge. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Afferent mechanisms underlying stimulation modality-related modulation of acupuncture-related cardiovascular responses.

    PubMed

    Zhou, Wei; Fu, Liang-Wu; Tjen-A-Looi, Stephanie C; Li, Peng; Longhurst, John C

    2005-03-01

    Despite the use of acupuncture to treat a number of heart diseases, little is known about the mechanisms that underlie its actions. Therefore, we examined the influence of acupuncture on sympathoexcitatory cardiovascular responses to gastric distension in anesthetized Sprague-Dawley rats. Thirty minutes of low-current, low-frequency, (0.3-0.5 mA, 2 Hz) electroacupuncture (EA), at P 5-6, S 36-37, and H 6-7 overlying the median, deep peroneal, and ulnar nerves significantly decreased reflex pressor responses by 40, 39, and 44%, respectively. In contrast, sham acupuncture involving needle insertion without stimulation at P 5-6 or 30 min of EA at LI 6-7 acupoints overlying the superficial radial nerve did not attenuate the reflex. Similarly, EA at P 5-6 using 40- or 100-Hz stimulation frequencies did not inhibit the reflex. Compared with EA at P 5-6, EA at two sets of acupoints, including P 5-6 and S 36-37, did not lead to larger inhibition of the reflex. Two minutes of manual acupuncture (MA; 2 Hz) at P 5-6 every 10 min for 30 min inhibited the reflex cardiovascular pressor response by 33%, a value not significantly different from 2-Hz EA at P 5-6. Single-unit afferent activity was not different between electrical stimulation (ES) and manual stimulation. However, 2-Hz ES activated more somatic afferents than 10- or 20-Hz ES. These data suggest that, although the location of acupoint stimulation and the frequency of stimulation determine the extent of influence of EA, there is little difference between low-frequency EA and MA at P 5-6. Furthermore, simultaneous stimulation using two acupoints that independently exert strong effects did not lead to an additive or a facilitative interaction. The similarity of the responses to EA and MA and the lack of cardiovascular response to high-frequency EA appear to be largely a function of somatic afferent responses.

  20. Cardiovascular and ventilatory responses to dorsal, facial, and whole-head water immersion in eupnea.

    PubMed

    Gagnon, Dominique D; Pretorius, Thea; McDonald, Gerren; Kenny, Glen P; Giesbrecht, Gordon G

    2013-06-01

    Facial cooling can regulate reflexes of the dive response whereas further body cooling generally induces the cold-shock response. We examined the cardiovascular and ventilatory parameters of these responses during 3-min immersions of the head dorsum, face, and whole head in 17 degrees C water while breathing was maintained. From a horizontal position, the head was inserted into a temperature controlled immersion tank in which the water level could be changed rapidly. On four occasions, either the head dorsum, face or whole head (prone and supine) were exposed to water. Mean decrease in heart rate (14%) and increases in systolic (9%) and diastolic (5%) blood pressures were seen during immersion. Relative mean finger skin blood flow had an early transient decrease (31%) for 90 s and then returned to baseline values. A strong transient increase was seen in minute ventilation (92%) at 20 s of immersion via tidal volume (85%). There were no consistent differences between the head dorsum, face, and whole head for all variables in response to immersion. The cold-shock response (increased minute ventilation and tidal volume) predominated over the dive response in the initial moments of immersion only. The order of emergence of these responses provides further recommendation to avoid head submersion upon cold water entry. It is important to protect the face, with a facemask, and the head dorsum, with an insulative hood, in cold water.

  1. Exaggerated sympathetic and cardiovascular responses to stimulation of the mesencephalic locomotor region in spontaneously hypertensive rats.

    PubMed

    Liang, Nan; Mitchell, Jere H; Smith, Scott A; Mizuno, Masaki

    2016-01-01

    The sympathetic and pressor responses to exercise are exaggerated in hypertension. However, the underlying mechanisms causing this abnormality remain to be fully elucidated. Central command, a neural drive originating in higher brain centers, is known to activate cardiovascular and locomotor control circuits concomitantly. As such, it is a viable candidate for the generation of the augmented vascular response to exercise in this disease. We hypothesized that augmentations in central command function contribute to the heightened cardiovascular response to exercise in hypertension. To test this hypothesis, changes in renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) in response to electrical stimulation of mesencephalic locomotor region (MLR; 20-50 μA in 10-μA steps evoking fictive locomotion), a putative component of the central command pathway, were examined in decerebrate, paralyzed normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Tibial nerve discharge during MLR stimulation significantly increased in an intensity-dependent manner in both WKY and SHR but was not different between groups. Stimulation of the MLR evoked significantly larger increases in RSNA and MAP with increasing stimulation intensity in both groups. Importantly, the increases in sympathetic and pressor responses to this fictive locomotion were significantly greater in SHR compared with WKY across all stimulation intensities (e.g., at 50 μA, ΔRSNA: WKY 153 ± 31%, SHR 287 ± 42%; ΔMAP: WKY 87 ± 9 mmHg, SHR 139 ± 7 mmHg). These findings provide the first evidence that central command may be a critical contributor to the exaggerated rise in sympathetic activity and blood pressure during exercise in hypertension. Copyright © 2016 the American Physiological Society.

  2. Hormonal contraception use alters stress responses and emotional memory.

    PubMed

    Nielsen, Shawn E; Segal, Sabrina K; Worden, Ian V; Yim, Ilona S; Cahill, Larry

    2013-02-01

    Emotionally arousing material is typically better remembered than neutral material. Since norepinephrine and cortisol interact to modulate emotional memory, sex-related influences on stress responses may be related to sex differences in emotional memory. Two groups of healthy women - one naturally cycling (NC women, n=42) and one using hormonal contraceptives (HC women, n=36) - viewed emotionally arousing and neutral images. Immediately after, they were assigned to Cold Pressor Stress (CPS) or a control procedure. One week later, participants received a surprise free recall test. Saliva samples were collected and later assayed for salivary alpha-amylase (biomarker for norepinephrine) and cortisol. Compared to NC women, HC women exhibited significantly blunted stress hormone responses to the images and CPS. Recall of emotional images differed between HC and NC women depending on noradrenergic and cortisol responses. These findings may have important implications for understanding the neurobiology of emotional memory disorders, especially those that disproportionately affect women.

  3. Cardiovascular responses to exercise as functions of absolute and relative work load

    NASA Technical Reports Server (NTRS)

    Lewis, S. F.; Taylor, W. F.; Graham, R. M.; Pettinger, W. A.; Schutte, J. E.; Blomqvist, C. G.

    1983-01-01

    The roles of absolute and relative oxygen uptake (VO2 and percent of muscle group specific VO2-max) as determinants of the cardiovascular and ventilatory responses to exercise over a wide range of active muscle mass are investigated. Experiments were conducted using four types of dynamic exercise: one-arm curl, one-arm cranking, and one and two-leg cycling at four different relative work loads (25, 50, 75, and 100 percent of VO2-max) for the corresponding muscle group. Results show that VO2 during maximal one-arm curl, one-arm cranking, and one-leg cycling averaged 20, 50, and 75 percent, respectively, of that for maximal two-leg cycling. Cardiac output was determined to be linearly related to VO2 with a similar slope and intercept for each type of exercise, and the heart rate at a given percent VO2-max was higher with larger active muscle mass. It is concluded that the cardiovascular responses to exercise was determined to a large extent by the active muscle mass and the absolute oxygen uptake, with the principal feature appearing to be the tight linkage between systematic oxygen transport and utilization.

  4. Acute cardiovascular responses while playing virtual games simulated by Nintendo Wii(®).

    PubMed

    Rodrigues, Gusthavo Augusto Alves; Felipe, Danilo De Souza; Silva, Elisangela; De Freitas, Wagner Zeferino; Higino, Wonder Passoni; Da Silva, Fabiano Fernandes; De Carvalho, Wellington Roberto Gomes; Aparecido de Souza, Renato

    2015-09-01

    [Purpose] This investigation evaluated the acute cardiovascular responses that occur while playing virtual games (aerobic and balance) emulated by Nintendo Wii(®). [Subjects] Nineteen healthy male volunteers were recruited. [Methods] The ergospirometric variables of maximum oxygen consumption, metabolic equivalents, and heart rate were obtained during the aerobic (Obstacle Course, Hula Hoop, and Free Run) and balance (Soccer Heading, Penguin Slide, and Table Tilt) games of Wii Fit Plus(®) software. To access and analyze the ergospirometric information, a VO2000 analyzer was used. Normalized data (using maximum oxygen consumption and heart rate) were analyzed using repeated measures analysis of variance and Scheffe's test. [Results] Significant differences were found among the balance and aerobic games in all variables analyzed. In addition, the Wii exercises performed were considered to be of light (balance games) and moderate (aerobic games) intensity in accordance with American College Sports Medicine exercise stratification. [Conclusion] Physical activity in a virtual environment emulated by Nintendo Wii(®) can change acute cardiovascular responses, primarily when Wii aerobic games are performed. These results support the use of the Nintendo Wii(®) in physical activity programs.

  5. Cardiovascular responses to cognitive stress in patients with migraine and tension-type headache

    PubMed Central

    Leistad, Rune B; Sand, Trond; Nilsen, Kristian B; Westgaard, Rolf H; Stovner, Lars Jacob

    2007-01-01

    Background The purpose of this study was to investigate the temporal relationship between autonomic changes and pain activation in migraine and tension-type headache induced by stress in a model relevant for everyday office-work. Methods We measured pain, blood pressure (BP), heart rate (HR) and skin blood flow (BF) during and after controlled low-grade cognitive stress in 22 migraineurs during headache-free periods, 18 patients with tension-type headache (TTH) and 44 healthy controls. The stress lasted for one hour and was followed by 30 minutes of relaxation. Results Cardiovascular responses to cognitive stress in migraine did not differ from those in control subjects. In TTH patients HR was maintained during stress, whereas it decreased for migraineurs and controls. A trend towards a delayed systolic BP response during stress was also observed in TTH. Finger BF recovery was delayed after stress and stress-induced pain was associated with less vasoconstriction in TTH during recovery. Conclusion It is hypothesized that TTH patients have different stress adaptive mechanisms than controls and migraineurs, involving delayed cardiovascular adaptation and reduced pain control system inhibition. PMID:17683636

  6. Cardiovascular responses to exercise as functions of absolute and relative work load

    NASA Technical Reports Server (NTRS)

    Lewis, S. F.; Taylor, W. F.; Graham, R. M.; Pettinger, W. A.; Schutte, J. E.; Blomqvist, C. G.

    1983-01-01

    The roles of absolute and relative oxygen uptake (VO2 and percent of muscle group specific VO2-max) as determinants of the cardiovascular and ventilatory responses to exercise over a wide range of active muscle mass are investigated. Experiments were conducted using four types of dynamic exercise: one-arm curl, one-arm cranking, and one and two-leg cycling at four different relative work loads (25, 50, 75, and 100 percent of VO2-max) for the corresponding muscle group. Results show that VO2 during maximal one-arm curl, one-arm cranking, and one-leg cycling averaged 20, 50, and 75 percent, respectively, of that for maximal two-leg cycling. Cardiac output was determined to be linearly related to VO2 with a similar slope and intercept for each type of exercise, and the heart rate at a given percent VO2-max was higher with larger active muscle mass. It is concluded that the cardiovascular responses to exercise was determined to a large extent by the active muscle mass and the absolute oxygen uptake, with the principal feature appearing to be the tight linkage between systematic oxygen transport and utilization.

  7. Associations between personal exposures to VOCs and alterations in cardiovascular physiology: Detroit Exposure and Aerosol Research Study (DEARS) - presentation

    EPA Science Inventory

    Introduction: An adult cohort consisting of 63 participants engaged in the US EPA’s recent Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study conducted during summer and winter periods over 3 years between 2004 and 2007...

  8. Associations between Personal Exposures to VOCs and Alterations in Cardiovascular Physiology: Detroit Exposure and Aerosol Research Study (DEARS)

    EPA Science Inventory

    Background: An adult cohort consisting of 63 participants engaged in the US EPA’s recent Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study conducted during summer and winter periods over 3 years between 2004 and 2007 (5 seas...

  9. Associations between Personal Exposures to VOCs and Alterations in Cardiovascular Physiology: Detroit Exposure and Aerosol Research Study (DEARS)

    EPA Science Inventory

    Background: An adult cohort consisting of 63 participants engaged in the US EPA’s recent Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study conducted during summer and winter periods over 3 years between 2004 and 2007 (5 seas...

  10. Associations between personal exposures to VOCs and alterations in cardiovascular physiology: Detroit Exposure and Aerosol Research Study (DEARS) - presentation

    EPA Science Inventory

    Introduction: An adult cohort consisting of 63 participants engaged in the US EPA’s recent Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study conducted during summer and winter periods over 3 years between 2004 and 2007...

  11. Endophytic fungi alter sucking bug responses to cotton reproductive structures.

    PubMed

    Sword, Gregory A; Tessnow, Ashley; Ek-Ramos, Maria Julissa

    2017-03-22

    All plants including cotton host a wide range of microorganisms as endophytes. There is a growing appreciation of the prevalence, ecological significance and management potential of facultative fungal endophytes in protecting plants from pests, pathogens and environmental stressors. Hemipteran sucking bugs have emerged as major pests across the US cotton belt, reducing yields directly by feeding on developing reproductive structures and indirectly by vectoring plant pathogens. We used no-choice and simultaneous choice assays to examine the host selection behavior of western tarnished plant bugs (Lygus hesperus) and southern green stink bugs (Nezara viridula) in response to developing flower buds and fruits from cotton plants colonized by one of two candidate beneficial fungal endophytes, Phialemonium inflatum or Beauveria bassiana. Both insect species exhibited strong negative responses to flower buds (L. hesperus) and fruits (N. viridula) from plants that had been colonized by candidate endophytic fungi relative to control plants under both no-choice and choice conditions. Behavioral responses of both species indicated that the insects were deterred prior to contact with plant tissues from endophyte-colonized plants, suggesting a putative role for volatile compounds in mediating the negative response. Our results highlight the role of fungal endophytes as plant mutualists that can have positive effects on plant resistance to pests. This article is protected by copyright. All rights reserved.

  12. Keratins Are Altered in Intestinal Disease-Related Stress Responses

    PubMed Central

    Helenius, Terhi O.; Antman, Cecilia A.; Asghar, Muhammad Nadeem; Nyström, Joel H.; Toivola, Diana M.

    2016-01-01

    Keratin (K) intermediate filaments can be divided into type I/type II proteins, which form obligate heteropolymers. Epithelial cells express type I-type II keratin pairs, and K7, K8 (type II) and K18, K19 and K20 (type I) are the primary keratins found in the single-layered intestinal epithelium. Keratins are upregulated during stress in liver, pancreas, lung, kidney and skin, however, little is known about their dynamics in the intestinal stress response. Here, keratin mRNA, protein and phosphorylation levels were studied in response to murine colonic stresses modeling human conditions, and in colorectal cancer HT29 cells. Dextran sulphate sodium (DSS)-colitis was used as a model for intestinal inflammatory stress, which elicited a strong upregulation and widened crypt distribution of K7 and K20. K8 levels were slightly downregulated in acute DSS, while stress-responsive K8 serine-74 phosphorylation (K8 pS74) was increased. By eliminating colonic microflora using antibiotics, K8 pS74 in proliferating cells was significantly increased, together with an upregulation of K8 and K19. In the aging mouse colon, most colonic keratins were upregulated. In vitro, K8, K19 and K8 pS74 levels were increased in response to lipopolysaccharide (LPS)-induced inflammation in HT29 cells. In conclusion, intestinal keratins are differentially and dynamically upregulated and post-translationally modified during stress and recovery. PMID:27626448

  13. Cardiovascular and autonomic alterations in rats with Parkinsonism induced by 6-OHDA and treated with L-DOPA.

    PubMed

    Silva, A S; Ariza, D; Dias, D P M; Crestani, C C; Martins-Pinge, M C

    2015-04-15

    Evaluate the effects caused by L-DOPA on cardiovascular and autonomic parameters in an animal model of Parkinsonism induced by 6-hydroxydopamine (6-OHDA). Adult male Wistar rats were subjected to bilateral microinfusion of 6-OHDA or saline (sham group) in the substantia nigra, and treated by gavage with L-DOPA or water for 7 days after surgery. On the 6th day the rats were subjected to femoral artery catheterization for cardiovascular recording. Mean arterial pressure (MAP) and heart rate (HR) were evaluated at baseline and during head up tilt (HUT) protocol. Spectral analysis of cardiovascular variability was performed using the V2.4 CardioSeries software v2.4. The lesion was quantified by dopamine levels in the striatum. Dopamine levels in the striatum were decreased in 6-OHDA rats (sham: 4.79 ± 0.49 ng/mg; 6-OHDA: 1.99 ± 0.68 ng/mg) and were not recovered by Prolopa treatment. Baseline values of MAP and HR were not different between groups. HUT induced an increase in MAP and HR (ΔMAP: 17 ± 1 mm Hg, ΔHR: 39 ± 4 bpm) that were attenuated in 6-OHDA and in Prolopa treated animals. At baseline, the systolic arterial pressure (SAP) variance was lower in the 6-OHDA AND sham prolopa groups. Spontaneous baroreflex sensitivity was higher at baseline in the 6-OHDA group as compared to all studied groups. Our data suggest that treatment with Prolopa did not interfere with cardiovascular variables at baseline. However, during HUT, the 6-OHDA and Prolopa control animals presented a lower cardiovascular compensation, suggesting a possible autonomic impairment in Parkinsonism induced by 6-OHDA.

  14. Adaptive thermoregulation in endotherms may alter responses to climate change.

    PubMed

    Boyles, Justin G; Seebacher, Frank; Smit, Ben; McKechnie, Andrew E

    2011-11-01

    Climate change is one of the major issues facing natural populations and thus a focus of recent research has been to predict the responses of organisms to these changes. Models are becoming more complex and now commonly include physiological traits of the organisms of interest. However, endothermic species have received less attention than have ectotherms in these mechanistic models. Further, it is not clear whether responses of endotherms to climate change are modified by variation in thermoregulatory characteristics associated with phenotypic plasticity and/or adaptation to past selective pressures. Here, we review the empirical data on thermal adaptation and acclimatization in endotherms and discuss how those factors may be important in models of responses to climate change. We begin with a discussion of why thermoregulation and thermal sensitivity at high body temperatures should be co-adapted. Importantly, we show that there is, in fact, considerable variation in the ability of endotherms to tolerate high body temperatures and/or high environmental temperatures, but a better understanding of this variation will likely be critical for predicting responses to future climatic scenarios. Next, we discuss why variation in thermoregulatory characteristics should be considered when modeling the effects of climate change on heterothermic endotherms. Finally, we review some biophysical and biochemical factors that will limit adaptation and acclimation in endotherms. We consider both long-term, directional climate change and short-term (but increasingly common) anomalies in climate such as extreme heat waves and we suggest areas of important future research relating to both our basic understanding of endothermic thermoregulation and the responses of endotherms to climate change.

  15. Resource colimitation governs plant community responses to altered precipitation

    PubMed Central

    Eskelinen, Anu; Harrison, Susan P.

    2015-01-01

    Ecological theory and evidence suggest that plant community biomass and composition may often be jointly controlled by climatic water availability and soil nutrient supply. To the extent that such colimitation operates, alterations in water availability caused by climatic change may have relatively little effect on plant communities on nutrient-poor soils. We tested this prediction with a 5-y rainfall and nutrient manipulation in a semiarid annual grassland system with highly heterogeneous soil nutrient supplies. On nutrient-poor soils, rainfall addition alone had little impact, but rainfall and nutrient addition synergized to cause large increases in biomass, declines in diversity, and near-complete species turnover. Plant species with resource-conservative functional traits (low specific leaf area, short stature) were replaced by species with resource-acquisitive functional traits (high specific leaf area, tall stature). On nutrient-rich soils, in contrast, rainfall addition alone caused substantial increases in biomass, whereas fertilization had little effect. Our results highlight that multiple resource limitation is a critical aspect when predicting the relative vulnerability of natural communities to climatically induced compositional change and diversity loss. PMID:26438856

  16. Microbial legacies alter decomposition in response to simulated global change

    PubMed Central

    Martiny, Jennifer BH; Martiny, Adam C; Weihe, Claudia; Lu, Ying; Berlemont, Renaud; Brodie, Eoin L; Goulden, Michael L; Treseder, Kathleen K; Allison, Steven D

    2017-01-01

    Terrestrial ecosystem models assume that microbial communities respond instantaneously, or are immediately resilient, to environmental change. Here we tested this assumption by quantifying the resilience of a leaf litter community to changes in precipitation or nitrogen availability. By manipulating composition within a global change experiment, we decoupled the legacies of abiotic parameters versus that of the microbial community itself. After one rainy season, more variation in fungal composition could be explained by the original microbial inoculum than the litterbag environment (18% versus 5.5% of total variation). This compositional legacy persisted for 3 years, when 6% of the variability in fungal composition was still explained by the microbial origin. In contrast, bacterial composition was generally more resilient than fungal composition. Microbial functioning (measured as decomposition rate) was not immediately resilient to the global change manipulations; decomposition depended on both the contemporary environment and rainfall the year prior. Finally, using metagenomic sequencing, we showed that changes in precipitation, but not nitrogen availability, altered the potential for bacterial carbohydrate degradation, suggesting why the functional consequences of the two experiments may have differed. Predictions of how terrestrial ecosystem processes respond to environmental change may thus be improved by considering the legacies of microbial communities. PMID:27740610

  17. Alterations in the Colonic Microbiota in Response to Osmotic Diarrhea

    PubMed Central

    Trajanoski, Slave; Lackner, Stefan; Stocker, Gernot; Hinterleitner, Thomas; Gülly, Christian; Högenauer, Christoph

    2013-01-01

    Background & Aims Diseases of the human gastrointestinal (GI) tract are often accompanied by diarrhea with profound alterations in the GI microbiota termed dysbiosis. Whether dysbiosis is due to the disease itself or to the accompanying diarrhea remains elusive. With this study we characterized the net effects of osmotic diarrhea on the composition of the GI microbiota in the absence of disease. Methods We induced osmotic diarrhea in four healthy adults by oral administration of polyethylene glycol 4000 (PEG). Stool as well as mucosa specimens were collected before, during and after diarrhea and 16S rDNA-based microbial community profiling was used to assess the microbial community structure. Results Stool and mucosal microbiotas were strikingly different, with Firmicutes dominating the mucosa and Bacteroidetes the stools. Osmotic diarrhea decreased phylotype richness and showed a strong tendency to equalize the otherwise individualized microbiotas on the mucosa. Moreover, diarrhea led to significant relative shifts in the phyla Bacteroidetes and Firmicutes and to a relative increase in the abundance of Proteobacteria on the mucosa, a phenomenon also noted in several inflammatory and diarrheal GI diseases. Conclusions Changes in microbial community structure induced by osmotic diarrhea are profound and show similarities to changes observed in other GI diseases including IBD. These effects so must be considered when specimens from diarrheal diseases (i.e. obtained by stratification of samples according to diarrheal status) or conditions wherein bowel preparations like PEG (i.e. specimens obtained during endoscopy) are used. PMID:23409050

  18. Effort and negative affect interact to predict cardiovascular responses to stress.

    PubMed

    Hilmert, Clayton J; Teoh, Ai Ni; Roy, Michael M

    2013-01-01

    Although traditional models posit that negative emotional responses to stress increase cardiovascular reactivity (CVR), laboratory studies have generally not found a strong emotion-CVR association. In this paper, we took a multidimensional approach to examining psychological reactions to stress in three studies. In each study we assessed the amount of effort exerted by a participant and the negative affect (NA) felt by the participant with different self-reported measures and an effort behavioural measure. Our findings consistently demonstrated that NA was associated with CVR when effort was relatively high, but not when effort was relatively low. This suggests that the weak NA-CVR correlations reported in past research may have been confounded by a third effort-related variable and that CVR is significantly associated with NA under certain circumstances. Furthermore, our findings suggest that by considering the multidimensional nature of psychological responses to stress, we may come to better understand the links between stress-related emotion and physiology.

  19. Model-based parameter estimation using cardiovascular response to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Heldt, T.; Shim, E. B.; Kamm, R. D.; Mark, R. G.

    2001-01-01

    This paper presents a cardiovascular model that is capable of simulating the short-term (< or approximately equal to 3 min) transient hemodynamic response to gravitational stress and a gradient-based optimization method that allows for the automated estimation of model parameters from simulated or experimental data. We perform a sensitivity analysis of the transient heart rate response to determine which parameters of the model impact the heart rate dynamics significantly. We subsequently include only those parameters in the estimation routine that impact the transient heart rate dynamics substantially. We apply the estimation algorithm to both simulated and real data and showed that restriction to the 20 most important parameters does not impair our ability to match the data.

  20. Model-based parameter estimation using cardiovascular response to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Heldt, T.; Shim, E. B.; Kamm, R. D.; Mark, R. G.

    2001-01-01

    This paper presents a cardiovascular model that is capable of simulating the short-term (< or approximately equal to 3 min) transient hemodynamic response to gravitational stress and a gradient-based optimization method that allows for the automated estimation of model parameters from simulated or experimental data. We perform a sensitivity analysis of the transient heart rate response to determine which parameters of the model impact the heart rate dynamics significantly. We subsequently include only those parameters in the estimation routine that impact the transient heart rate dynamics substantially. We apply the estimation algorithm to both simulated and real data and showed that restriction to the 20 most important parameters does not impair our ability to match the data.

  1. Cardiovascular responses of the chronically instrumented monkey during simulated space flight

    NASA Technical Reports Server (NTRS)

    Mccutcheon, E. P.; Carlson, E.; Mains, R. C.; Pace, N.; Rahlmann, D. F.; Sandler, H.

    1982-01-01

    A pod enclosure system designed by the Environmental Physiology Laboratory at the University of California at Berkeley is found to be eminently suitable for work with monkeys. The pattern of cardiovascular activity is found to vary. In the first half of the exposure, the hourly mean values suggest an initial period of instability, most marked for heart rate, beginning at 'launch.' In the second half of the exposure, the final three days, the responses appear much more ordered, with a stable phase relationship between circadian shifts in heart rate and mean aortic pressure. Since the latter stability is more normal, the assumption is made that the animal had become adjusted to its situation. Imposition of a daily lower body negative pressure (LBNP) stress shows characteristic responses.

  2. Spheroid growth in ovarian cancer alters transcriptome responses for stress pathways and epigenetic responses.

    PubMed

    Paullin, Trillitye; Powell, Chase; Menzie, Christopher; Hill, Robert; Cheng, Feng; Martyniuk, Christopher J; Westerheide, Sandy D

    2017-01-01

    Ovarian cancer is the most lethal gynecological cancer, with over 200,000 women diagnosed each year and over half of those cases leading to death. These poor statistics are related to a lack of early symptoms and inadequate screening techniques. This results in the cancer going undetected until later stages when the tumor has metastasized through a process that requires the epithelial to mesenchymal transition (EMT). In lieu of traditional monolayer cell culture, EMT and cancer progression in general is best characterized through the use of 3D spheroid models. In this study, we examine gene expression changes through microarray analysis in spheroid versus monolayer ovarian cancer cells treated with TGFβ to induce EMT. Transcripts that included Coiled-Coil Domain Containing 80 (CCDC80), Solute Carrier Family 6 (Neutral Amino Acid Transporter), Member 15 (SLC6A15), Semaphorin 3E (SEMA3E) and PIF1 5'-To-3' DNA Helicase (PIF1) were downregulated more than 10-fold in the 3D cells while Inhibitor Of DNA Binding 2, HLH Protein (ID2), Regulator Of Cell Cycle (RGCC), Protease, Serine 35 (PRSS35), and Aldo-Keto Reductase Family 1, Member C1 (AKR1C1) were increased more than 50-fold. Interestingly, EMT factors, stress responses and epigenetic processes were significantly affected by 3D growth. The heat shock response and the oxidative stress response were also identified as transcriptome responses that showed significant changes upon 3D growth. Subnetwork enrichment analysis revealed that DNA integrity (e.g. DNA damage, genetic instability, nucleotide excision repair, and the DNA damage checkpoint pathway) were altered in the 3D spheroid model. In addition, two epigenetic processes, DNA methylation and histone acetylation, were increased with 3D growth. These findings support the hypothesis that three dimensional ovarian cell culturing is physiologically different from its monolayer counterpart.

  3. Spheroid growth in ovarian cancer alters transcriptome responses for stress pathways and epigenetic responses

    PubMed Central

    Paullin, Trillitye; Powell, Chase; Menzie, Christopher; Hill, Robert; Cheng, Feng; Martyniuk, Christopher J.

    2017-01-01

    Ovarian cancer is the most lethal gynecological cancer, with over 200,000 women diagnosed each year and over half of those cases leading to death. These poor statistics are related to a lack of early symptoms and inadequate screening techniques. This results in the cancer going undetected until later stages when the tumor has metastasized through a process that requires the epithelial to mesenchymal transition (EMT). In lieu of traditional monolayer cell culture, EMT and cancer progression in general is best characterized through the use of 3D spheroid models. In this study, we examine gene expression changes through microarray analysis in spheroid versus monolayer ovarian cancer cells treated with TGFβ to induce EMT. Transcripts that included Coiled-Coil Domain Containing 80 (CCDC80), Solute Carrier Family 6 (Neutral Amino Acid Transporter), Member 15 (SLC6A15), Semaphorin 3E (SEMA3E) and PIF1 5'-To-3' DNA Helicase (PIF1) were downregulated more than 10-fold in the 3D cells while Inhibitor Of DNA Binding 2, HLH Protein (ID2), Regulator Of Cell Cycle (RGCC), Protease, Serine 35 (PRSS35), and Aldo-Keto Reductase Family 1, Member C1 (AKR1C1) were increased more than 50-fold. Interestingly, EMT factors, stress responses and epigenetic processes were significantly affected by 3D growth. The heat shock response and the oxidative stress response were also identified as transcriptome responses that showed significant changes upon 3D growth. Subnetwork enrichment analysis revealed that DNA integrity (e.g. DNA damage, genetic instability, nucleotide excision repair, and the DNA damage checkpoint pathway) were altered in the 3D spheroid model. In addition, two epigenetic processes, DNA methylation and histone acetylation, were increased with 3D growth. These findings support the hypothesis that three dimensional ovarian cell culturing is physiologically different from its monolayer counterpart. PMID:28793334

  4. The interstitial fluid content in working muscle modifies the cardiovascular response to exercise.

    PubMed

    Schütze, H; Hildebrandt, W; Stegemann, J

    1991-01-01

    The volume of interstitial fluid in the limbs varies considerably, due to hydrostatic effects. As signals from working muscle, responsible for much of the cardiovascular drive, are assumed to be transmitted in this compartment, blood pressure and heart rate could be affected by local or systemic variations in interstitial hydration. Using a special calf ergometer, eight male subjects performed rhythmic aerobic plantar flexions in a supine position with dependent calves for periods of 7 min. During exercise heart rate, blood pressure, oxygen uptake (VO2) and blood lactate concentrations were measured in two different tests, one before and after interstitial calf dehydration through limb elevation for 25 min, compared to the other, a control with unaltered fluid volume in a maintained working position. Impedance plethysmography showed calf volume to be stabilized in the control position. Leg elevation by passive hip flexion to 90 degrees resulted in a fast (vascular) volume decrease lasting less than 2 min, followed by a slow linear fluid loss from the interstitial compartment. Then, when returned to the control position, adjustment of vascular volume was completed within 2 min and exercise could be performed with dehydration remaining in the interstitium only. Cardiovascular response was identical at the start of both tests. However, exercising with dehydrated calves elicited a significantly larger increase in heart rate compared to the control, whereas VO2 was identical. The blood pressure response was shown to be only slightly enhanced. Structural interstitial features varying with hydration, most likely chemical or mechanical ones, may have been responsible for this amplification of signals.

  5. Assessment of cardiovascular response to treadmill exercise in normal healthy Indian adolescents.

    PubMed

    Pande, Sushma S; Pande, Santosh R; Dhore, Rajendra B; Daphale, Ajay V; Parate, Vrushali R; Patel, Shishir S; Agrekar, Sushil H

    2012-01-01

    The study aims to assess the cardiovascular response to treadmill exercise test in healthy Indian adolescents. A group of 50 healthy adolescents took part in the study. Cardiovascular response was assessed by using treadmill exercise test as per Bruce protocol. Pulse rate, blood pressure and ECG were recorded before, during and after undertaking the treadmill test. Mean age and body mass index (BMI) were 18.7 +/- 0.51 yrs. and 21.4 +/- 3.44 kg/m2 respectively. Karl Pearson Correlation analysis showed highly significant negative correlation between BMI and exercise time (r = -0.598, P<0.001) and between resting DBP and Exercise Time (r = -0.424, P<0.002). While BMI and DBP showed highly significant positive correlation (r = 0.463, P<0.001). During exercise pulse and SBP rose and DBP fell. SBP rose from mean 122 to 175 (rise by 53 mm of Hg) and DBP fell from mean 78 to 65 (fall by 13 mm of Hg). One min recovery pulse was 156 indicating 22% fall from target heart rate. All the parameters returned to near resting value at 6 min recovery. In 30% students DBP showed exaggerated response i.e. rise during exercise. These students had more BMI and higher resting DBP as compared to other students, which could be the reason for exaggerated response in these participants. In ECG there were no significant ST/T changes during exercise or recovery period. This study provides normal data for small sample of healthy Indian adolescents when subjected to treadmill exercise test.

  6. Effects of medullary administration of a nitric oxide precursor on cardiovascular responses and neurotransmission during static exercise following ischemic stroke.

    PubMed

    Phattanarudee, Siripan; Towiwat, Pasarapa; Maher, Timothy J; Ally, Ahmmed

    2013-07-01

    We have reported that in rats with a 90 min left middle cerebral artery occlusion (MCAO) and 24 h reperfusion, pressor responses during muscle contractions were attenuated, as were glutamate concentrations in the left rostral ventrolateral medulla (RVLM) and left caudal VLM (CVLM), but gamma-aminobutyric acid (GABA) levels increased in left RVLM and CVLM. This study determined the effects of L-arginine, a nitric oxide (NO) precursor, within the RVLM and (or) CVLM on cardiovascular activity and glutamate/GABA levels during static exercise in left-sided MCAO rats. Microdialysis of L-arginine into left RVLM had a greater attenuation of cardiovascular responses, a larger decrease in glutamate, and a significant increase in GABA levels during muscle contractions in stroke rats. Administration of N(G)-monomethyl-L-arginine, an NO-synthase inhibitor, reversed the effects. In contrast, L-arginine administration into left CVLM evoked a greater potentiation of cardiovascular responses, increased glutamate, and decreased GABA levels during contractions in stroked rats. However, L-arginine administration into both left RVLM and left CVLM elicited responses similar to its infusion into the left RVLM. These results suggest that NO within the RVLM and CVLM modulates cardiovascular responses and glutamate/GABA neurotransmission during static exercise following stroke, and that a RVLM-NO mechanism has a dominant effect in the medullary regulation of cardiovascular function.

  7. Alterations in immune responses in prenatally irradiated dogs

    SciTech Connect

    Nold, J.B.; Benjamin, S.A.; Miller, G.K.

    1988-09-01

    Immunologic responses were studied in beagle dogs following prenatal (35 days gestation) irradiation to evaluate the effects of ionizing radiation on the developing immune system. Each dog received 1.5 Gy /sup 60/Co gamma irradiation or sham irradiation. Prenatally irradiated dogs exhibited a significant reduction in primary humoral antibody responses to inoculated sheep red blood cells, a T-dependent antigen, and a concurrent decrease in T-helper lymphocyte subpopulations in the peripheral blood at 3 to 4 months of age. Similarly, irradiated fetuses have been shown to have defects in epitheliostromal development of the thymus. It is suggested that the postnatal immunologic deficits may relate to the prenatal thymic injury.

  8. Matricryptic sites control tissue injury responses in the cardiovascular system: relationships to pattern recognition receptor regulated events.

    PubMed

    Davis, George E

    2010-03-01

    This review addresses new concepts related to the importance of how cells within the cardiovascular system respond to matricryptic sites generated from the extracellular matrix (ECM) following tissue injury. A model is presented whereby matricryptic sites exposed from the ECM result in activation of multiple cell surface receptors including integrins, scavenger receptors, and toll-like receptors which together are hypothesized to coactivate downstream signaling pathways which alter cell behaviors following tissue injury. Of great interest are the relationships between matricryptic fragments of ECM called matricryptins and other stimuli that activate cells during injury states such as released components from cells (DNA, RNA, cytoskeletal components such as actin) or products from infectious agents in innate immunity responses. These types of cell activating molecules, which are composed of repeating molecular elements, are known to interact with pattern recognition receptors that (i) are expressed from cell surfaces, (ii) are released from cells following tissue injury, or (iii) circulate as components of plasma. Thus, cell recognition of matricryptic sites from the ECM appears to be an important component of a broad cell and tissue sensory system to detect and respond to environmental cues generated following varied types of tissue injury.

  9. Anthropogenic noise alters dwarf mongoose responses to heterospecific alarm calls.

    PubMed

    Morris-Drake, Amy; Bracken, Anna M; Kern, Julie M; Radford, Andrew N

    2017-04-01

    Anthropogenic noise is an evolutionarily novel and widespread pollutant in both terrestrial and aquatic habitats. Despite increasing evidence that the additional noise generated by human activities can affect vocal communication, the majority of research has focused on the use of conspecific acoustic information, especially sexual signals. Many animals are known to eavesdrop on the alarm calls produced by other species, enhancing their likelihood of avoiding predation, but how this use of heterospecific information is affected by anthropogenic noise has received little empirical attention. Here, we use two field-based playback experiments on a habituated wild population of dwarf mongooses (Helogale parvula) to determine how anthropogenic noise influences the response of foragers to heterospecific alarm calls. We begin by demonstrating that dwarf mongooses respond appropriately to the alarm calls of sympatric chacma baboons (Papio ursinus) and tree squirrels (Paraxerus cepapi); fleeing only to the latter. We then show that mongoose foragers are less likely to exhibit this flee response to tree squirrel alarm calls during road-noise playback compared to ambient-sound playback. One explanation for the change in response is that noise-induced distraction or stress result in maladaptive behaviour. However, further analysis revealed that road-noise playback results in increased vigilance and that mongooses showing the greatest vigilance increase are those that do not subsequently exhibit a flee response to the alarm call. These individuals may therefore be acting appropriately: if the greater gathering of personal information indicates the absence of an actual predator despite an alarm call, the need to undertake costly fleeing behaviour can be avoided. Either way, our study indicates the potential for anthropogenic noise to interfere with the use of acoustic information from other species, and suggests the importance of considering how heterospecific networks are

  10. Phosphorus source alters host plant response to ectomycorrhizal diversity.

    PubMed

    Baxter, James W; Dighton, John

    2005-11-01

    We examined the influence of phosphorus source and availability on host plant (Pinus rigida) response to ectomycorrhizal diversity under contrasting P conditions. An ectomycorrhizal richness gradient was established with equimolar P supplied as either inorganic phosphate or organic inositol hexaphosphate. We measured growth and N and P uptake of individual P. rigida seedlings inoculated with one, two, or four species of ectomycorrhizal fungi simultaneously and without mycorrhizas in axenic culture. Whereas colonization of P. rigida by individual species of ectomycorrhizal fungi decreased with increasing fungal richness, colonization of all species combined increased. Plant biomass and N content increased across the ectomycorrhizal richness gradient in the organic but not the inorganic P treatment. Plants grown under organic P conditions had higher N concentration than those grown under inorganic P conditions, but there was no effect of richness. Phosphorus content of plants grown in the organic P treatment increased with increasing ectomycorrhizal richness, but there was no response in the inorganic P treatment. Phosphorus concentration was higher in plants grown at the four-species richness level in the organic P treatment, but there was no effect of diversity under inorganic P conditions. Overall, few ectomycorrhizal composition effects were found on plant growth or nutrient status. Phosphatase activities of individual ectomycorrhizal fungi differed under organic P conditions, but there was no difference in total root system phosphatase expression between the inorganic or organic P treatments or across richness levels. Our results provide evidence that plant response to ectomycorrhizal diversity is dependent on the source and availability of P.

  11. Assessment of the effect of anthropometric data on the alterations of cardiovascular parameters in Lithuanian elite male basketball players during physical load.

    PubMed

    Žumbakytė-Šermukšnienė, Renata; Kajėnienė, Alma; Berškienė, Kristina; Daunoravičienė, Algė; Sederevičiūtė-Kandratavičienė, Rasa

    2012-01-01

    OBJECTIVES. The aim of the study was to assess the effect of the anthropometric data of basketball players on the alterations of cardiovascular parameters during the physical load applying the model of integrated evaluation. MATERIAL AND METHODS. The research sample consisted of 113 healthy Caucasian male basketball players, candidates of the Lithuanian National men's basketball teams. Basketball players were divided into 2 groups: 69 taller and heavier male basketball players (with a higher percentage of body fat) (TMB) and 44 shorter and less heavy male basketball players (with a lower percentage of body fat) (SMB). The amount of fat, expressed in percentage, was measured using the body composition analyzer TBF-300. "Kaunas-Load," a computerized ECG analysis system, was used to evaluate the functional condition of the cardiovascular system during the load. RESULTS. The TMB group had a lower heart rate during the warming-up phase and the steady state of the load as compared with the SMB group (P<0.05). The JT interval in the TMB group was greater during the warming-up and the steady state as compared with the SMB group (P<0.05). The JT/RR ratio index in the TMB group was found to be lower in the warming-up phase and in the steady state compared with the respective parameter in the SMB group (P<0.05). CONCLUSIONS. The cardiovascular system of taller and heavier male basketball players with a greater relative amount of body fat functioned more economically.

  12. Additive Effects of Sinusoidal Lower Body Negative Pressure on Cardiovascular Responses.

    PubMed

    Ishibashi, Keita; Oyama, Fuyuki; Yoshida, Hisao; Iwanaga, Koichi

    2017-02-01

    Sinusoidal lower body negative pressure (SLBNP) has been used to investigate the cardiovascular response to slow periodic changes in blood shifts, but measurements of slow fluctuations take a long time if measured for each period of SLBNP separately. Our study aimed to investigate whether the cardiovascular responses to superimposed SLBNP (S-SLBNP), which is expected to reduce the measurement time, are different from responses measured individually. S-SLBNP was configured by superimposing two conventional SLBNPs (C-SLBNP) at 180-s and 30-s periods in the pressure range from 0 to -25 mmHg. As the S-SLBNP has double the static load of C-SLBNP, we also used offset SLBNP (O-SLBNP), which has the same static load level as S-SLBNP. Heart rate (HR), thoracic impedance (Z0), and mean arterial pressure (MAP) were measured from 11 male subjects. The transfer functions of gains from MAP to HR (Gain-HR/MAP) and from Z0 to HR (Gain-HR/Z0) were calculated as indexes of arterial baroreflex and cardiopulmonary baroreflex regulation of HR, respectively. The Gain-HR/MAP in the 180-s period (2.11 ± 0.17 bpm/mmHg; mean ± SEM) was larger than that of the 30-s period (1.04 ± 0.09 bpm/mmHg); however, there was no significant difference between the SLBNP conditions. The Gain-HR/Z0 in C-SLBNP (9.37 ± 1.47 bpm/ohm) was smaller than that of the other conditions [18.46 ± 2.45 bpm/ohm (O-SLBNP); 16.09 ± 2.29 bpm/ohm (S-SLBNP)]. Using S-SLBNP could reduce the measurement time needed to examine the arterial baroreflex. However, the cardiopulmonary baroreflex was modified by the static load of SLBNP.Ishibashi K, Oyama F, Yoshida H, Iwanaga K. Additive effects of sinusoidal lower body negative pressure on cardiovascular responses. Aerosp Med Hum Perform. 2017; 88(2):137-141.

  13. Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness

    PubMed Central

    Oliveira-Silva, Iransé; Leicht, Anthony S.; Moraes, Milton R.; Simões, Herbert G.; Del Rosso, Sebastián; Córdova, Cláudio; Boullosa, Daniel A.

    2016-01-01

    The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5–39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26–45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness (r = 0.43 to 0.51; −0.53 to −0.52) and body composition (r = −0.63 to −0.43; 0.48–0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being. PMID:28082914

  14. Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness.

    PubMed

    Oliveira-Silva, Iransé; Leicht, Anthony S; Moraes, Milton R; Simões, Herbert G; Del Rosso, Sebastián; Córdova, Cláudio; Boullosa, Daniel A

    2016-01-01

    The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5-39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26-45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness (r = 0.43 to 0.51; -0.53 to -0.52) and body composition (r = -0.63 to -0.43; 0.48-0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being.

  15. The role of autacoids and the autonomic nervous system in cardiovascular responses to radio-frequency energy heating.

    PubMed

    Jauchem, J R

    2006-04-01

    Among the potential effects of exposure to high levels of radio-frequency energy (RFE) (which includes microwaves), an increase in body temperature is the primary consequence. Release of autacoids and activity of the autonomic nervous system may influence (or be directly responsible for) some of the physiological changes that occur in conjunction with this hyperthermia. The main focus of this review is the interaction of autacoids and the autonomic nervous system with cardiovascular changes during heating. Differences between environmental and RFE-induced heating (such as rate of temperature change and degree of skin vs. core heating) may be important when considering these effects. Antihistamines exhibited no beneficial effect on circulatory collapse during RFE-induced heating. The serotonergic blocker methysergide decreased survival time in rats during terminal RFE exposure, despite no effects on heart rate (HR) or blood pressure. Although blockade of platelet-activating factor resulted in lower HR before RFE exposure, there was a lack of effect on the subsequent increase in HR during heating. Nitric oxide did not contribute to the hypotension that occurs due to rapid heating by RFE exposure. There have been either no or very limited studies of effects of prostaglandins, bradykinin, or angiotensin on RFE-induced heating responses. beta-Adrenoceptor antagonism with propranolol resulted in significantly decreased survival times and lower final colonic temperatures during RFE exposure. A lack of effects of nadolol on survival time and temperature, coupled with its poor ability to traverse the blood-brain barrier, suggests that central beta-adrenergic stimulation rather than peripheral stimulation may alter thermoregulation. Effects of the autonomic nervous system (as studied by adrenoceptor blockade) on potassium changes during heating have not been fully investigated. Such changes could be important in animals' responses to RFE and other modalities of heating, and

  16. Peripheral tumors alter neuroinflammatory responses to lipopolysaccharide in female rats.

    PubMed

    Pyter, Leah M; El Mouatassim Bih, Sarah; Sattar, Husain; Prendergast, Brian J

    2014-03-13

    Cancer is associated with an increased prevalence of depression. Peripheral tumors induce inflammatory cytokine production in the brain and depressive-like behaviors. Mounting evidence indicates that cytokines are part of a pathway by which peripheral inflammation causes depression. Neuroinflammatory responses to immune challenges can be exacerbated (primed) by prior immunological activation associated with aging, early-life infection, and drug exposure. This experiment tested the hypothesis that peripheral tumors likewise induce neuroinflammatory sensitization or priming. Female rats with chemically-induced mammary carcinomas were injected with either saline or lipopolysaccharide (LPS, 250μg/kg; i.p.), and expression of mRNAs involved in the pathway linking inflammation and depression (interleukin-1beta [Il-1β], CD11b, IκBα, indolamine 2,3-deoxygenase [Ido]) was quantified by qPCR in the hippocampus, hypothalamus, and frontal cortex, 4 or 24h post-treatment. In the absence of LPS, hippocampal Il-1β and CD11b mRNA expression were elevated in tumor-bearing rats, whereas Ido expression was reduced. Moreover, in saline-treated rats basal hypothalamic Il-1β and CD11b expression were positively correlated with tumor weight; heavier tumors, in turn, were characterized by more inflammatory, necrotic, and granulation tissue. Tumors exacerbated CNS proinflammatory gene expression in response to LPS: CD11b was greater in hippocampus and frontal cortex of tumor-bearing relative to tumor-free rats, IκBα was greater in hippocampus, and Ido was greater in hypothalamus. Greater neuroinflammatory responses in tumor-bearing rats were accompanied by attenuated body weight gain post-LPS. The data indicate that neuroinflammatory pathways are potentiated, or primed, in tumor-bearing rats, which may exacerbate future negative behavioral consequences.

  17. Neonatal Amygdala Lesions Alter Responsiveness to Objects in Juvenile Macaques

    PubMed Central

    Bliss-Moreau, Eliza; Toscano, Jessica E.; Bauman, Melissa; Mason, William A.; Amaral, David G.

    2013-01-01

    The amygdala is widely recognized to play a central role in emotional processing. In nonhuman primates, the amygdala appears to be critical for generating appropriate behavioral responses in emotionally salient contexts. One common finding is that macaque monkeys that receive amygdala lesions as adults are behaviorally uninhibited in the presence of potentially dangerous objects. While control animals avoid these objects, amygdala-lesioned animals readily interact with them. Despite a large literature documenting the role of the amygdala in emotional processing in adult rhesus macaques, little research has assessed the role of the amygdala across the macaque neurodevelopmental trajectory. We assessed the behavioral responses of three-year-old (juvenile) rhesus macaques that received bilateral ibotenic acid lesions of the amygdala or hippocampus at two weeks of age. Animals were presented with salient objects known to produce robust fear-related responses in macaques (e.g., snakes and reptile-like objects), mammal-like objects that included animal-like features (e.g., eyes and mouths) but not reptile-like features (e.g., scales), and non-animal objects. The visual complexity of objects was scaled to vary the objects' salience. In contrast to control and hippocampus-lesioned animals, amygdale-lesioned animals were uninhibited in the presence of potentially dangerous objects. They readily retrieved food rewards placed near these objects and physically explored the objects. Furthermore, while control and hippocampus-lesioned animals differentiated between levels of object complexity, amygdala-lesioned animals did not. Taken together, these findings suggest that early damage to the amygdala, like damage during adulthood, permanently compromises emotional processing. PMID:21215794

  18. Cardiovascular and endocrine responses to acute hypoxaemia during and following dexamethasone infusion in the ovine fetus

    PubMed Central

    Fletcher, Andrew J W; Gardner, David S; Edwards, C Mark B; Fowden, Abigail L; Giussani, Dino A

    2003-01-01

    This study investigated the effects of fetal treatment with dexamethasone on ovine fetal cardiovascular defence responses to acute hypoxaemia, occurring either during or 48 h following the period of glucocorticoid exposure. To address the mechanisms underlying these responses, chemoreflex function and plasma concentrations of catecholamines, neuropeptide Y (NPY) and vasopressin were measured. Under general halothane anaesthesia, 26 Welsh Mountain sheep fetuses were surgically prepared for long-term recording at between 117 and 120 days of gestation (dGA; term is ∼145 days) with vascular catheters and a Transonic flow probe around a femoral artery. Following at least 5 days of recovery, fetuses were randomly assigned to one of two experimental groups. After 48 h of baseline recording, at 125 ± 1 dGA, half of the fetuses (n = 13) were continuously infused i.v. with dexamethasone for 48 h at a rate of 2.06 ± 0.13 μg kg−1 h−1. The remaining 13 fetuses were infused with heparinized saline at the same rate (controls). At 127 ± 1 dGA, 2 days from the onset of infusions, seven fetuses from each group were subjected to 1 h of acute hypoxaemia. At 129 ± 1 dGA, 2 days after the end of infusions, six fetuses from each group were subjected to 1 h of acute hypoxaemia. Similar reductions in fetal partial pressure of arterial oxygen occurred in control and dexamethasone-treated fetuses during the acute hypoxaemia protocols. In control fetuses, acute hypoxaemia led to transient bradycardia, femoral vasoconstriction and significant increases in plasma concentrations of catecholamines, vasopressin and NPY. In fetuses subjected to acute hypoxaemia during dexamethasone treatment, the increase in plasma NPY was enhanced, the bradycardic response was prolonged, and the plasma catecholamine and vasopressin responses were diminished. In fetuses subjected to acute hypoxaemia 48 h following dexamethasone treatment, femoral vasoconstriction and plasma catecholamine and vasopressin

  19. Effects of acute and chronic sleep deprivation on cardiovascular regulation.

    PubMed

    Tobaldini, E; Pecis, M; Montano, N

    2014-01-01

    Sleep is a fundamental physiological process, characterized by the activation of several cortical and subcortical neural networks. The relation between sleep and cardiovascular system is complex and bidirectional: sleep disorders may alter cardiovascular system, leading to an increased cardiovascular risk, while, on the contrary, cardio- vascular diseases are characterized by an alteration of physiological sleep. Autonomic nervous system (ANS) plays a key role in the regulation of cardiovascular functions during different sleep stages, with sympatho-vagal balance dynamically shifting towards sympathetic or vagal predominance across different sleep stages. Sleep deprivation (SD) has becoming one of the most relevant health problem in modern societies. SD can be related to aging, which is associated with increased sleep fragmentation, and to sleep disorders, such as sleep disordered breathing and neurological disorders. Experimental studies in animals showed that SD significantly affects cardiovascular functions, altering heart rate and blood pressure responses, and increasing sympathetic activity and neuroendocrine response to stressor stimuli. Clinical studies in humans have shown that SD, either due to experimental sleep loss and to sleep disorders, can affect different biological pathways, such as cardiovascular autonomic control, inflammation, immunity responses and metabolism. All these alterations may predispose subjects with SD to an increased cardiovascular risk. Hence, it is fundamental to identify the presence of a sleep disorder, which could be per se responsible for sleep loss, or the presence of sleep deprivation due to other factors, such as social life, habits etc., in order to identify subjects at high risk for cardiovascular events.

  20. Positive emotional style and subjective, cardiovascular and cortisol responses to acute laboratory stress.

    PubMed

    Bostock, Sophie; Hamer, Mark; Wawrzyniak, Andrew J; Mitchell, Ellen S; Steptoe, Andrew

    2011-09-01

    The relationships between positive emotional style and acute salivary cortisol and cardiovascular responses to laboratory stress tasks were examined in 40 young women (mean age=28.8 years). Positive emotional style (PES) was measured by aggregating daily positive mood rating scales over one week. Negative affect was assessed with the short form Profile of Mood States. Salivary cortisol was measured in response to two behavioural tasks, a 5 min speech task and a 5 min mirror tracing task. Blood pressure (BP) and heart rate responses were monitored using a Finometer during baseline, tasks and recovery. Higher PES was associated with more complete diastolic BP recovery (p=0.027) and lower acute cortisol response to stress (p=0.018), after adjusting for baseline measures, age, BMI and negative affect. Individuals with higher PES reported lower subjective tension during the tasks and perceived the tasks as more controllable. There were no differences in ratings of task involvement or in objective measures of task performance. A retrospective measure of positive affect (POMS vigour) was associated with diastolic BP recovery but not cortisol responses or subjective tension. The findings suggest that positive affective traits, assessed using repeated assessments of daily mood, are related to adaptive recovery from acute psychological stress. Our results reinforce evidence linking positive affect with adaptive diastolic BP recovery, while extending the results to cortisol. Investigations into the biological correlates of affective traits should consider utilising repeated measures of experienced affect.

  1. Propionyl-L-carnitine Corrects Metabolic and Cardiovascular Alterations in Diet-Induced Obese Mice and Improves Liver Respiratory Chain Activity

    PubMed Central

    Mingorance, Carmen; Duluc, Lucie; Chalopin, Matthieu; Simard, Gilles; Ducluzeau, Pierre-Henri; Herrera, Maria Dolores; Alvarez de Sotomayor, Maria; Andriantsitohaina, Ramaroson

    2012-01-01

    Aims Obesity is a primary contributor to acquired insulin resistance leading to the development of type 2 diabetes and cardiovascular alterations. The carnitine derivate, propionyl-L-carnitine (PLC), plays a key role in energy control. Our aim was to evaluate metabolic and cardiovascular effects of PLC in diet-induced obese mice. Methods C57BL/6 mice were fed a high-fat diet for 9 weeks and then divided into two groups, receiving either free- (vehicle-HF) or PLC-supplemented water (200 mg/kg/day) during 4 additional weeks. Standard diet-fed animals were used as lean controls (vehicle-ST). Body weight and food intake were monitored. Glucose and insulin tolerance tests were assessed, as well as the HOMAIR, the serum lipid profile, the hepatic and muscular mitochondrial activity and the tissue nitric oxide (NO) liberation. Systolic blood pressure, cardiac and endothelial functions were also evaluated. Results Vehicle-HF displayed a greater increase of body weight compared to vehicle-ST that was completely reversed by PLC treatment without affecting food intake. PLC improved the insulin-resistant state and reversed the increased total cholesterol but not the increase in free fatty acid, triglyceride and HDL/LDL ratio induced by high-fat diet. Vehicle-HF exhibited a reduced cardiac output/body weight ratio, endothelial dysfunction and tissue decrease of NO production, all of them being improved by PLC treatment. Finally, the decrease of hepatic mitochondrial activity by high-fat diet was reversed by PLC. Conclusions Oral administration of PLC improves the insulin-resistant state developed by obese animals and decreases the cardiovascular risk associated to this metabolic alteration probably via correction of mitochondrial function. PMID:22457831

  2. Cardiovascular and endocrine responses to cutaneous electrical stimulation after fentanyl in the ovine fetus.

    PubMed

    Smith, Richard P; Miller, Suzanne L; Igosheva, Natalia; Peebles, Donald M; Glover, Vivette; Jenkin, Graham; Hanson, Mark A; Fisk, Nicholas M

    2004-03-01

    The purpose of this study was to determine whether physical stimulation is stressful to the ovine fetus, as judged from physiologic changes that are similar to those reported for other stressors (such as hypoxia); whether any stress response could be blocked by clinically used doses of fentanyl; and whether fentanyl alone had any potentially deleterious physiologic effects in the fetus. We investigated the effect of fentanyl analgesia on the cardiovascular and endocrine response to cutaneous electrical stimulation in the late gestation (>125 days) ovine fetus (n=7 fetuses). Chronically implanted catheters and blood flow probes were used to measure fetal arterial blood pressure, heart rate, carotid and femoral blood flow, pH, Po(2), Pco(2), lactate, cortisol, and beta-endorphin levels before, during, and for 1 hour after 5 minutes of cutaneous electrical stimulation to the lip, forelimb, and abdomen, in a crossover design. Clinically used 30 or 150 microg doses of fentanyl (which approximated 10 or 50 microg/kg estimated fetal weight) or saline solution were given intravenously to the fetus 2 minutes before stimulation. When compared with the control, stimulation caused a significant rise in fetal heart rate (P=.003; mean maximal rise, 48.6+/-14.0 beats/min, 0-10 minutes after the start of stimulation) but caused no change in any other parameters studied. Neither dose of fentanyl attenuated the changes in heart rate that were observed in response to stimulation alone. Fentanyl alone significantly increased fetal heart rate, carotid blood flow, and lactate and cortisol levels and significantly decreased pH and Po(2). Cutaneous electrical stimulation in the fetal sheep causes an increase in heart rate, which fentanyl does not block. Fentanyl itself has significant effects on the cardiovascular and endocrine system, which might adversely affect the fetus.

  3. Attenuation of Cardiovascular Responses and Upper Airway Events to Tracheal Extubation by Low Dose Propofol

    PubMed Central

    Moein Vaziri, Mohammad Taghy; Jouybar, Reza; Moein Vaziri, Nader; Moein Vaziri, Najmeh; Panah, Ashkan

    2013-01-01

    Background Hemodynamic changes and respiratory tract complications are often followed by tracheal extubation. These events may be dangerous in neurosurgical patients and those with cardiovascular disease or at an old age. Objectives The aim of this study is to investigate the attenuation of cardiovascular responses and upper airway events resulting from tracheal extubation by low dose propofol. Materials and Methods 80 patients with ASA physical status I, undergoing an elective surgery in a double blind manner received 0.5mg/kg propofol or normal saline 2 minutes before extubation. Heart rate and blood pressure and quality of tracheal extubation were recorded. Results Heart rate and blood pressure in patients receiving propofol were less than the control group (P < 0.05) at the time of injection of propofol, but there were no differences between the two groups at the time of extubation. Conclusions We concluded that propofol can reduce SBP, DBP, MAP, HR & cough production at the time of injection but there were no significant changes in these parameters after extubation. PMID:24083001

  4. Anhedonia and effort mobilization in dysphoria: reduced cardiovascular response to reward and punishment.

    PubMed

    Brinkmann, Kerstin; Schüpbach, Laurent; Joye, Isabelle Ancel; Gendolla, Guido H E

    2009-12-01

    Instigated by evidence for reduced responsiveness to reward in depression, the present two studies addressed the question if such anhedonic behavior would also become evident in reduced mobilization of mental effort in terms of cardiovascular reactivity. Undergraduates completed the Center for Epidemiologic Studies-Depression Scale (CES-D) and worked on mental tasks, expecting either no consequence, a performance-contingent reward, or a performance-contingent punishment. Study 1 revealed that participants with low CES-D scores showed high systolic blood pressure reactivity in the punishment condition, whereas participants with high CES-D scores showed low systolic reactivity. Study 2 corroborated this finding for reward: Nondysphoric participants expecting a reward showed higher reactivity of systolic blood pressure and pre-ejection period than participants in the neutral condition or than dysphoric participants. Together, the studies demonstrate that reward insensitivity in (subclinical) depression is also found in cardiovascular reactivity. Furthermore, dysphoric individuals do not respond to punishment either, suggesting a general insensitivity to hedonic consequences.

  5. Bupropion response on sleep quality in patients with depression: implications for increased cardiovascular disease risk

    PubMed Central

    Schramm, Preetam J.; Poland, Russell E.; Rao, Uma

    2013-01-01

    Depression could be an independent risk factor for cardiovascular disease. We assessed bupropion response in depressed patients by polysomnography (PSG) and cardiopulmonary coupling (CPC) variables. Nineteen subjects participated in a two-session, two consecutive night PSG protocol. Participants received either placebo or bupropion-SR 150 mg, orally, in a randomized, double-blind cross-over fashion on night two. Outcome variables were: sleep stages, REM latency, stable, unstable sleep and very low frequency coupling (VLFC). CPC analysis uses heart rate variability and the electrocardiogram’s R-wave amplitude fluctuations associated with respiration to generate frequency maps. Bupropion increased REM latency (p=0.043) but did not impact PSG sleep continuity, architecture and CPC variables. A trend (p=0.092) was observed towards increasing VLFC duration. Bupropion increased the number of stable-unstable sleep transitions (p=0.036). Moderate to strong correlations between PSG and CPC variables were found on placebo and bupropion nights. Limitations include a small sample size, limited power to detect CPC changes and lack of normal controls for comparison. Increased stable-unstable sleep transitions and VLFC duration may indicate vulnerability to cardiovascular disease due to their association with low heart rate variability that has been associated with increased mortality raising the question whether the beneficial effects of the antidepressant medication outweighs the impact on cardiopulmonary dynamics. PMID:24239431

  6. Repressed anger and patterns of cardiovascular, self-report and behavioral responses: effects of harassment.

    PubMed

    Burns, J W; Evon, D; Strain-Saloum, C

    1999-12-01

    We hypothesized that anger repressors would show discrepancies between self-reported anger and cardiovascular and behavioral responses only during harassment. Subjects (N=102) were assigned randomly to condition. In the nonharassment condition, subjects told stories about eight Thematic Apperception Test cards without any harassment. In the harassment condition, subjects told four stories without harassment, and then told four more stories with harassment. Words connoting aggressive behavior and angry/hostile affect were coded from story content. Subjects were classified into low anger expressor, anger repressor, high anger expressor, and defensive anger expressor categories based on median splits of the Anger-Out Subscale and Marlowe-Crowne Social Desirability Scale. Results showed that harassed anger repressors reported anger comparable to that of low anger expressors but less than high expressors, whereas their heart rate (HR) reactivity was comparable to high expressors, but greater than low anger expressors. Increases in anger words did not distinguish repressors from other groups. Repressed anger may represent a distinct anger management style characterized by a discrepancy between acknowledged anger and cardiovascular reactivity--effects that become fully manifest only during interpersonal provocation.

  7. Perceived Social Support, Coping Styles, and Chinese Immigrants’ Cardiovascular Responses to Stress

    PubMed Central

    Lee, Christine; Suchday, Sonia; Wylie-Rosett, Judith

    2011-01-01

    Background Social support and coping strategies are important determinants of health, especially for those in the immigrant community adjusting to a new environment. Purpose This study assessed the buffering effects of perceived social support and different coping styles on cardiovascular reactivity to stress among Chinese immigrants in the New York City Chinatown area. Method Participants (N = 50, 76% women, and 22–84 years old) completed questionnaires assessing their perceived social support and coping strategy preferences. They were then asked to recall a stress provoking event related to their immigration experience in a semi-structured interview format. Results Hierarchical multiple regression analyses confirmed the interaction effect between perceived social support and problem-focused, emotion-focused, or reappraisal coping on heart rate reactivity. Additionally, Chinese immigrants who upheld more Chinese values were highly correlated with stronger perceived availability of social support and were more likely to incorporate the use of problem-focused and reappraisal coping styles. Conclusion Findings suggest that high level of social support and the use of reappraisal coping strategies were associated with attenuated cardiovascular responses to stress. PMID:21472482

  8. Perceived social support, coping styles, and Chinese immigrants' cardiovascular responses to stress.

    PubMed

    Lee, Yuen Shan Christine; Suchday, Sonia; Wylie-Rosett, Judith

    2012-06-01

    Social support and coping strategies are important determinants of health, especially for those in the immigrant community adjusting to a new environment. This study assessed the buffering effects of perceived social support and different coping styles on cardiovascular reactivity to stress among Chinese immigrants in the New York City Chinatown area. Participants (N = 50, 76% women, and 22-84 years old) completed questionnaires assessing their perceived social support and coping strategy preferences. They were then asked to recall a stress-provoking event related to their immigration experience in a semi-structured interview format. Hierarchical multiple regression analyses confirmed the interaction effect between perceived social support and problem-focused, emotion-focused, or reappraisal coping on heart rate reactivity. Additionally, Chinese immigrants who upheld more Chinese values were highly correlated with stronger perceived availability of social support and were more likely to incorporate the use of problem-focused and reappraisal coping styles. Findings suggest that high level of social support and the use of reappraisal coping strategies were associated with attenuated cardiovascular responses to stress.

  9. Bupropion response on sleep quality in patients with depression: implications for increased cardiovascular disease risk.

    PubMed

    Schramm, Preetam J; Poland, Russell E; Rao, Uma

    2014-02-01

    Depression could be an independent risk factor for cardiovascular disease. We assessed bupropion response in depressed patients by polysomnography (PSG) and cardiopulmonary coupling (CPC) variables. Nineteen subjects participated in a two-session, two consecutive night PSG protocol. Participants received either placebo or bupropion-SR 150 mg, orally, in a randomized, double-blind cross-over fashion on night two. Outcome variables were: sleep stages, REM latency, stable, unstable sleep and very low frequency coupling (VLFC). CPC analysis uses heart rate variability and the electrocardiogram's R-wave amplitude fluctuations associated with respiration to generate frequency maps. Bupropion increased REM latency (p=0.043) but did not impact PSG sleep continuity, architecture and CPC variables. A trend (p=0.092) was observed towards increasing VLFC duration. Bupropion increased the number of stable-unstable sleep transitions (p=0.036). Moderate to strong correlations between PSG and CPC variables were found on placebo and bupropion nights. Limitations include a small sample size, limited power to detect CPC changes and lack of normal controls for comparison. Increased stable-unstable sleep transitions and VLFC duration may indicate vulnerability to cardiovascular disease due to their association with low heart rate variability that has been associated with increased mortality raising the question whether the beneficial effects of the antidepressant medication outweighs the impact on cardiopulmonary dynamics. © 2013 Elsevier B.V. and ECNP All rights reserved.

  10. Minimum anesthetic concentration and cardiovascular dose-response relationship of isoflurane in cinereous vultures (Aegypius monachus).

    PubMed

    Kim, Young K; Lee, Scott S; Suh, Euy H; Lee, Lyon; Lee, Hee C; Lee, Hyo J; Yeon, Seong C

    2011-09-01

    This study aimed to determine the minimum anesthetic concentration (MAC) and dose-related cardiovascular effects of isoflurane during controlled ventilation in cinereous vultures (Aegypius monachus). The MAC was determined for 10 cinereous vultures as the midpoint between the end-tidal isoflurane concentration that allows gross purposeful movement and that which prevents the movement in response to clamping a pedal digit. Immediately after the MAC was determined, the cardiovascular effects of isoflurane at 1.0, 1.5, and 2.0 times the MAC were investigated in seven of the 10 birds. The MAC of isoflurane for 10 cinereous vultures during controlled ventilation was 1.06 +/- 0.07% (mean +/- SD). When the isoflurane concentration was increased to 1.5 and 2.0 times the MAC, there was significant dose-dependent decrease in the arterial blood pressure. However, the heart rate did not change over a range of 1.0 to 2.0 times the MAC.

  11. Evaluation of Anxiety Induced Cardiovascular Response in known Hypertensive Patients Undergoing Exodontia - A Prospective Study

    PubMed Central

    Rayapati, Dilip Kumar; Puttiah, Raghuveer Hosahalli; Tavane, Prashanth; Singh, Shobha Eswara; Rangan, Vinod; Kalakunta, Prithvi Raj

    2016-01-01

    Introduction Anxiety towards exodontic procedures is a common occurrence in dental practice. In hypertensive patients this anxiety induced stress may have an effect on cardiovascular system which may be clinically significant. Aim To evaluate the cardiovascular changes in hypertensive patients that may manifest following anxiety induced stress in patients undergoing exodontic procedures under local anaesthesia. Materials and Methods Eighty known hypertensive patients under medication reporting to Department of Oral and Maxillofacial surgery, Dayananda Sagar College of Dental Sciences Bangalore, Karnataka, India for extraction of teeth were taken up for the study. Anxiety was measured before local anaesthetic delivery using Amsterdam Pre-operative Anxiety and Information Scale (APAIS). Cardiovascular response data including blood pressure, heart rate, pulse rate, oxygen saturation and electrocardiographic changes were measured pre-operatively, immediately after local anaesthesia administration and Post-operatively at five, ten and fifteen minutes interval. Kruskal-Wallis test was used to compare continuous variables before and after the injection of local anaesthesia including heart rate, pulse rate, oxygen saturation, and blood pressure. Repeated-measures analysis of variance (ANOVA) was used to analyse the significance of changes in heart rate, pulse rate, blood pressure, and oxygen saturation over time between groups.Chi-square test was used to analyse the significance of electrocardiographic changes Results The results revealed that the mean anxiety score before administration of local anaesthetic was 9.91(S.D ±2.9) with a range 4-20. Severe preoperative anxiety (<12) was associated with significantly increased heart rate, pulse rate, systolic blood pressure. At the pre-injection phase the mean values were systolic blood pressure (130.72±9.2), diastolic blood pressure (81.6±7.7), heart rate (72.7±11.9) and oxygen saturation (95.2±1.9). These values were

  12. Evaluation of Anxiety Induced Cardiovascular Response in known Hypertensive Patients Undergoing Exodontia - A Prospective Study.

    PubMed

    Balasubramaniyan, Nathiya; Rayapati, Dilip Kumar; Puttiah, Raghuveer Hosahalli; Tavane, Prashanth; Singh, Shobha Eswara; Rangan, Vinod; Kalakunta, Prithvi Raj

    2016-08-01

    Anxiety towards exodontic procedures is a common occurrence in dental practice. In hypertensive patients this anxiety induced stress may have an effect on cardiovascular system which may be clinically significant. To evaluate the cardiovascular changes in hypertensive patients that may manifest following anxiety induced stress in patients undergoing exodontic procedures under local anaesthesia. Eighty known hypertensive patients under medication reporting to Department of Oral and Maxillofacial surgery, Dayananda Sagar College of Dental Sciences Bangalore, Karnataka, India for extraction of teeth were taken up for the study. Anxiety was measured before local anaesthetic delivery using Amsterdam Pre-operative Anxiety and Information Scale (APAIS). Cardiovascular response data including blood pressure, heart rate, pulse rate, oxygen saturation and electrocardiographic changes were measured pre-operatively, immediately after local anaesthesia administration and Post-operatively at five, ten and fifteen minutes interval. Kruskal-Wallis test was used to compare continuous variables before and after the injection of local anaesthesia including heart rate, pulse rate, oxygen saturation, and blood pressure. Repeated-measures analysis of variance (ANOVA) was used to analyse the significance of changes in heart rate, pulse rate, blood pressure, and oxygen saturation over time between groups.Chi-square test was used to analyse the significance of electrocardiographic changes. The results revealed that the mean anxiety score before administration of local anaesthetic was 9.91(S.D ±2.9) with a range 4-20. Severe preoperative anxiety (<12) was associated with significantly increased heart rate, pulse rate, systolic blood pressure. At the pre-injection phase the mean values were systolic blood pressure (130.72±9.2), diastolic blood pressure (81.6±7.7), heart rate (72.7±11.9) and oxygen saturation (95.2±1.9). These values were increased immediately after local anaesthetic

  13. Key ecological responses to nitrogen are altered by climate ...

    EPA Pesticide Factsheets

    Here we review the effects of nitrogen and climate (e.g. temperature and precipitation) on four aspects of ecosystem structure and function including hydrologic-coupled nitrogen cycling, carbon cycling, acidification and biodiversity. Ecosystems are simultaneously exposed to multiple stressors; two dominant drivers threatening ecosystems are anthropogenic nitrogen loading and climate change. Evaluating the cumulative effects of these stressors provides a holistic view of ecosystem vulnerability, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our current knowledge of the cumulative effects of these stressors is growing, but limited. The goal of this paper is to synthesize the state of scientific knowledge on how ecosystems are affected by the interactions of meteorlogic/climatic factors (e.g., temperature and precipitation) and nitrogen addition. Understanding the interactions of meteorlogic/climatic factors and nitrogen will help to inform how current and projected variability may affect ecosystem response.

  14. Key ecological responses to nitrogen are altered by climate ...

    EPA Pesticide Factsheets

    Here we review the effects of nitrogen and climate (e.g. temperature and precipitation) on four aspects of ecosystem structure and function including hydrologic-coupled nitrogen cycling, carbon cycling, acidification and biodiversity. Ecosystems are simultaneously exposed to multiple stressors; two dominant drivers threatening ecosystems are anthropogenic nitrogen loading and climate change. Evaluating the cumulative effects of these stressors provides a holistic view of ecosystem vulnerability, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our current knowledge of the cumulative effects of these stressors is growing, but limited. The goal of this paper is to synthesize the state of scientific knowledge on how ecosystems are affected by the interactions of meteorlogic/climatic factors (e.g., temperature and precipitation) and nitrogen addition. Understanding the interactions of meteorlogic/climatic factors and nitrogen will help to inform how current and projected variability may affect ecosystem response.

  15. Species Interactions Alter Evolutionary Responses to a Novel Environment

    PubMed Central

    Lawrence, Diane; Fiegna, Francesca; Behrends, Volker; Bundy, Jacob G.; Phillimore, Albert B.; Bell, Thomas; Barraclough, Timothy G.

    2012-01-01

    Studies of evolutionary responses to novel environments typically consider single species or perhaps pairs of interacting species. However, all organisms co-occur with many other species, resulting in evolutionary dynamics that might not match those predicted using single species approaches. Recent theories predict that species interactions in diverse systems can influence how component species evolve in response to environmental change. In turn, evolution might have consequences for ecosystem functioning. We used experimental communities of five bacterial species to show that species interactions have a major impact on adaptation to a novel environment in the laboratory. Species in communities diverged in their use of resources compared with the same species in monocultures and evolved to use waste products generated by other species. This generally led to a trade-off between adaptation to the abiotic and biotic components of the environment, such that species evolving in communities had lower growth rates when assayed in the absence of other species. Based on growth assays and on nuclear magnetic resonance (NMR) spectroscopy of resource use, all species evolved more in communities than they did in monocultures. The evolutionary changes had significant repercussions for the functioning of these experimental ecosystems: communities reassembled from isolates that had evolved in polyculture were more productive than those reassembled from isolates that had evolved in monoculture. Our results show that the way in which species adapt to new environments depends critically on the biotic environment of co-occurring species. Moreover, predicting how functioning of complex ecosystems will respond to an environmental change requires knowing how species interactions will evolve. PMID:22615541

  16. Species interactions alter evolutionary responses to a novel environment.

    PubMed

    Lawrence, Diane; Fiegna, Francesca; Behrends, Volker; Bundy, Jacob G; Phillimore, Albert B; Bell, Thomas; Barraclough, Timothy G

    2012-01-01

    Studies of evolutionary responses to novel environments typically consider single species or perhaps pairs of interacting species. However, all organisms co-occur with many other species, resulting in evolutionary dynamics that might not match those predicted using single species approaches. Recent theories predict that species interactions in diverse systems can influence how component species evolve in response to environmental change. In turn, evolution might have consequences for ecosystem functioning. We used experimental communities of five bacterial species to show that species interactions have a major impact on adaptation to a novel environment in the laboratory. Species in communities diverged in their use of resources compared with the same species in monocultures and evolved to use waste products generated by other species. This generally led to a trade-off between adaptation to the abiotic and biotic components of the environment, such that species evolving in communities had lower growth rates when assayed in the absence of other species. Based on growth assays and on nuclear magnetic resonance (NMR) spectroscopy of resource use, all species evolved more in communities than they did in monocultures. The evolutionary changes had significant repercussions for the functioning of these experimental ecosystems: communities reassembled from isolates that had evolved in polyculture were more productive than those reassembled from isolates that had evolved in monoculture. Our results show that the way in which species adapt to new environments depends critically on the biotic environment of co-occurring species. Moreover, predicting how functioning of complex ecosystems will respond to an environmental change requires knowing how species interactions will evolve.

  17. Computer-mediated communication and time pressure induce higher cardiovascular responses in the preparatory and execution phases of cooperative tasks.

    PubMed

    Costa Ferrer, Raquel; Serrano Rosa, Miguel Ángel; Zornoza Abad, Ana; Salvador Fernández-Montejo, Alicia

    2010-11-01

    The cardiovascular (CV) response to social challenge and stress is associated with the etiology of cardiovascular diseases. New ways of communication, time pressure and different types of information are common in our society. In this study, the cardiovascular response to two different tasks (open vs. closed information) was examined employing different communication channels (computer-mediated vs. face-to-face) and with different pace control (self vs. external). Our results indicate that there was a higher CV response in the computer-mediated condition, on the closed information task and in the externally paced condition. These role of these factors should be considered when studying the consequences of social stress and their underlying mechanisms.

  18. Do metaboreceptors alter heat loss responses following dynamic exercise?

    PubMed

    McGinn, Ryan; Swift, Brendan; Binder, Konrad; Gagnon, Daniel; Kenny, Glen P

    2014-01-01

    Metaboreceptor activation during passive heating is known to influence cutaneous vascular conductance (CVC) and sweat rate (SR). However, whether metaboreceptors modulate the suppression of heat loss following dynamic exercise remains unclear. On separate days, before and after 15 min of high-intensity treadmill running in the heat (35°C), eight males underwent either 1) no isometric handgrip exercise (IHG) or ischemia (CON), 2) 1 min IHG (60% of maximum, IHG), 3) 1 min IHG followed by 2 min of ischemia (IHG+OCC), 4) 2 min of ischemia (OCC), or 5) 1 min IHG followed by 2 min of ischemia with application of lower body negative pressure (IHG+LBNP). SR (ventilated capsule), cutaneous blood flow (Laser-Doppler), and mean arterial pressure (Finometer) were measured continuously before and after dynamic exercise. Following dynamic exercise, CVC was reduced with IHG exercise (P < 0.05) and remained attenuated with post-IHG ischemia during IHG+OCC relative to CON (39 ± 2 vs. 47 ± 6%, P < 0.05). Furthermore, the reduction in CVC was exacerbated by application of LBNP during post-IHG ischemia (35 ± 3%, P < 0.05) relative to IHG+OCC. SR increased during IHG exercise (P < 0.05) and remained elevated during post-IHG ischemia relative to CON following dynamic exercise (0.94 ± 0.15 vs. 0.53 ± 0.09 mg·min(-1)·cm(-2), P < 0.05). In contrast, application of LBNP during post-IHG ischemia had no effect on SR (0.93 ± 0.09 mg·min(-1)·cm(-2), P > 0.05) relative to post-IHG ischemia during IHG+OCC. We show that CVC is reduced and that SR is increased by metaboreceptor activation following dynamic exercise. In addition, we show that the metaboreflex-induced loading of the baroreceptors can influence the CVC response, but not the sweating response.

  19. Cardiovascular and single-unit responses to L-glutamate injection into the posterior insular cortex in rat.

    PubMed

    Ranjbar, A; Hatam, M; Nasimi, A

    2015-10-15

    The insular cortex in rat is a longitudinal strip that runs along the rostral half of the rhinal fissure. The previous studies showed connections between the posterior insular cortex (PIC) and some major cardiovascular centers. Based on the stimulation site, electrical or chemical stimulation of the PIC induced an increase or a decrease in blood pressure (BP) and heart rate (HR). There is no report of simultaneous cardiovascular and single-unit recording microinjection of Glut in the PIC. In this study, L-glutamate was microinjected into the PIC of urethane anesthetized rats and arterial pressure, HR and single-unit responses were recorded simultaneously. Also the response of the neurons to baroreceptor activation was explored. Glut produced five types of long oscillatory, pressor, depressor, bradycardic and tachycardic cardiovascular responses, with no association between pressure and HR responses. We also observed five single-unit responses, consisting of short excitatory, long oscillatory, excitatory, inhibitory and mixed responses. There was an association between oscillation in BP and in single-unit response. There were some differences between the two sides especially for single-unit responses. In conclusion, there were five types of cardiovascular and five types of single-unit responses, to Glut microinjection into PIC, from which three types were correlated. The left side of the PIC is involved more in the cardiovascular functions. These data along with the fact that most recorded neurons responded to baroreceptor activation, might imply the presence of feedback systems in the PIC, producing irregularity in BP and HR. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Anesthetic doses blocking adrenergic (stress) and cardiovascular responses to incision--MAC BAR.

    PubMed

    Roizen, M F; Horrigan, R W; Frazer, B M

    1981-05-01

    The reaction to stress, while vital to the conscious animal, may be detrimental to the surgical patient. To assess the stress-ablating action of different anesthetics (halothane, enflurane, morphine, and spinal) and anesthetic doses, we studied the responses in plasma norepinephrine, muscle movement, pupil diameter, heart rate, and blood pressure to induction of anesthesia and incision in 170 unpremedicated healthy adults. The age-adjusted dose (mean +/- SD) of anesthesia that blocked the adrenergic response in 50 per cent of individuals who had a skin incision (MAC BAR) was 1.45 +/- 0.08 MAC for halothane, 1.60 +/- 0.13 MAC for enflurane, or 1.13 +/- 0.09 +/- mg/kg for morphine sulfate (each anesthetic was given with 60 per cent nitrous oxide). No patient with a level of spinal anesthesia that blocked the pain of incision had an adrenergic response to incision. Increasing doses of halothane and morphine were associated with less of a cardiovascular response to incision (as measured by rate-pressure product); this was not true for enflurane. No patient with an adequate level of spinal anesthesia had a cardiovascular response to skin incision. The changes in heart rate, blood pressure, rate-pressure product, and plasma norepinephrine content that occurred with induction of anesthesia tended to equalize these values between patients, regardless of anesthetic dose, and for all individual and combined anesthetics. That is, if a patient's heart rate while awake was below 63 beats/min, heart rate tended to rise 58 per cent of the difference between heart rate while awake and 63 beats/min, and vice versa. Similarly, the change in blood pressure with induction averaged 75 per cent of the difference between systolic blood pressure while awake and 88 torr. The average for the change in rate-pressure product with induction was 79 per cent of the difference between rate-pressure product while awake and 5917 torr.beats/min. It was concluded that all the anesthetics tested can

  1. Wanting and liking in dysphoria: Cardiovascular and facial EMG responses during incentive processing.

    PubMed

    Franzen, Jessica; Brinkmann, Kerstin

    2016-12-01

    Theories and research on depression point to reduced responsiveness during reward anticipation and in part also during punishment anticipation. They also suggest weaker affective responses to reward consumption and unchanged affective responses to punishment consumption. However, studies investigating incentive anticipation using effort mobilization and incentive consumption using facial expressions are scarce. The present studies tested reward and punishment responsiveness in a subclinically depressed sample, manipulating a monetary reward (Study 1) and a monetary punishment (Study 2). Effort mobilization was operationalized as cardiovascular reactivity, while facial expressions were measured by facial electromyographic reactivity. Compared to nondysphorics, dysphorics showed reduced pre-ejection period (PEP) reactivity and blunted self-reported wanting during reward anticipation but reduced PEP reactivity and normal self-reported wanting during punishment anticipation. Compared to nondysphorics, dysphorics showed reduced zygomaticus major muscle reactivity and blunted self-reported liking during reward consumption but normal corrugator supercilii muscle reactivity and normal self-reported disliking during punishment consumption. Copyright © 2016. Published by Elsevier B.V.

  2. Respiratory and cardiovascular responses to manual chest percussion in normal subjects.

    PubMed

    Dallimore, Kate; Jenkins, Sue; Tucker, Beatrice

    1998-01-01

    The respiratory and cardiovascular responses to manual chest percussion were studied in seven naive healthy subjects. Percussion during quiet breathing, percussion with thoracic expansion exercises (TEE) and TEE alone were applied to subjects in side-lying. Inspired volume, oxygen consumption, oxygen saturation, heart rate and blood pressure were measured before, during and after each technique. Significant increases in inspired volume and heart rate occurred with all three techniques (p < 0.01). Oxygen consumption increased with all three techniques however only the increases during percussion with TEE, and TEE alone were significant (p < 0.01). Oxygen saturation increased with percussion with TEE and TEE alone (p < 0.01). No significant changes in blood pressure were observed.

  3. Emergency Spatiotemporal Shift: The Response of Protein Kinase D to Stress Signals in the Cardiovascular System.

    PubMed

    Wood, Brent M; Bossuyt, Julie

    2017-01-01

    Protein Kinase D isoforms (PKD 1-3) are key mediators of neurohormonal, oxidative, and metabolic stress signals. PKDs impact a wide variety of signaling pathways and cellular functions including actin dynamics, vesicle trafficking, cell motility, survival, contractility, energy substrate utilization, and gene transcription. PKD activity is also increasingly linked to cancer, immune regulation, pain modulation, memory, angiogenesis, and cardiovascular disease. This increasing complexity and diversity of PKD function, highlights the importance of tight spatiotemporal control of the kinase via protein-protein interactions, post-translational modifications or targeting via scaffolding proteins. In this review, we focus on the spatiotemporal regulation and effects of PKD signaling in response to neurohormonal, oxidant and metabolic signals that have implications for myocardial disease. Precise targeting of these mechanisms will be crucial in the design of PKD-based therapeutic strategies.

  4. Emergency Spatiotemporal Shift: The Response of Protein Kinase D to Stress Signals in the Cardiovascular System

    PubMed Central

    Wood, Brent M.; Bossuyt, Julie

    2017-01-01

    Protein Kinase D isoforms (PKD 1-3) are key mediators of neurohormonal, oxidative, and metabolic stress signals. PKDs impact a wide variety of signaling pathways and cellular functions including actin dynamics, vesicle trafficking, cell motility, survival, contractility, energy substrate utilization, and gene transcription. PKD activity is also increasingly linked to cancer, immune regulation, pain modulation, memory, angiogenesis, and cardiovascular disease. This increasing complexity and diversity of PKD function, highlights the importance of tight spatiotemporal control of the kinase via protein–protein interactions, post-translational modifications or targeting via scaffolding proteins. In this review, we focus on the spatiotemporal regulation and effects of PKD signaling in response to neurohormonal, oxidant and metabolic signals that have implications for myocardial disease. Precise targeting of these mechanisms will be crucial in the design of PKD-based therapeutic strategies. PMID:28174535

  5. Adiposity Indexes as Phenotype-Specific Markers of Preclinical Metabolic Alterations and Cardiovascular Risk in Polycystic Ovary Syndrome: A Cross-Sectional Study.

    PubMed

    Mario, Fernanda Missio; Graff, Scheila Karen; Spritzer, Poli Mara

    2017-02-15

    Polycystic ovary syndrome (PCOS) is a common condition in women of reproductive age. 2 PCOS phenotypes (classic and ovulatory) are currently recognized as the most prevalent, with important differences in terms of cardiometabolic features. We studied the performance of different adiposity indexes to predict preclinical metabolic alterations and cardiovascular risk in 234 women with PCOS (173 with classic and 61 with ovulatory PCOS) and 129 controls. Performance of waist circumference, waist-to-height ratio, conicity index, lipid accumulation product, and visceral adiposity index was assessed based on HOMA-IR ≥ 3.8 as reference standard for screening preclinical metabolic alterations and cardiovascular risk factors in each group. Lipid accumulation product had the best accuracy for classic PCOS, and visceral adiposity index had the best accuracy for ovulatory PCOS. By applying the cutoff point of lipid accumulation product<34, we identified a subgroup of patients without cardiometabolic alterations (P<0.05) in the group with classic PCOS, a population at higher risk for hypertension, dyslipidemia, and impaired glucose tolerance. In ovulatory PCOS, vi