Analysis of hemodynamic variability after sinoaortic denervation in the conscious rat

1986 ◽  
Vol 251 (6) ◽  
pp. R1163-R1169 ◽  
Author(s):  
A. J. Trapani ◽  
K. W. Barron ◽  
M. J. Brody
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Mesenteric Arteries ◽  
Conscious Rat ◽  
Mean Values ◽  
Regional Vascular Resistance ◽  
Renal Vascular ◽  
Relationship Of ◽  
The Relationship

The present study was undertaken to determine the regional hemodynamic basis for increased mean arterial pressure (MAP) variability produced by sinoaortic baroreceptor denervation (SAD) in the conscious rat. Sinoaortic-denervated and intact rats were instrumented chronically with a catheter placed in the femoral artery and pulsed-Doppler flow probes positioned on the renal and superior mesenteric arteries and the lower abdominal aorta to determine MAP, heart rate, and regional vascular resistance. Each cardiovascular variable was sampled once per minute during a 1-h recording period. Compared with control animals, baroreceptor-denervated animals exhibited greater variability of MAP and mesenteric, renal, and hindquarter resistances 7–9 days after SAD. The variability of heart rate was similar when animals from the two groups were compared. The pattern of significant correlation for the relationship of MAP to vascular resistance in the different beds was not consistent for individual SAD and intact animals. Finally, a wider distribution of mean values was observed for the individuals within the SAD group for MAP, heart rate, and hindquarter and renal vascular resistances. We conclude that SAD produces greater fluctuation of vascular resistance in several beds which contributes to the increased lability of MAP; however, there is no predictable pattern of vascular resistance lability which underlies the variability of arterial pressure.

Mechanisms of pressor response produced by stimulation of nucleus ambiguus

1990 ◽  
Vol 259 (5) ◽  
pp. R955-R962
Author(s):  
B. H. Machado ◽  
M. J. Brody
Keyword(s):  
Arterial Pressure ◽  
Vascular Resistance ◽  
Pressor Response ◽  
Nucleus Ambiguus ◽  
Ventrolateral Medulla ◽  
Pressor Responses ◽  
Regional Vascular Resistance ◽  
Parasympathetic Control ◽  
Renal Vascular ◽  
Stimulation Of

We showed previously that activation of nucleus ambiguus (NA) induced bradycardia and increased arterial pressure. In this study, we compared responses produced by electrical and chemical (glutamate) stimulation of NA and adjacent rostral ventrolateral medulla (RVLM). Equivalent pressor responses were elicited from both areas. However: 1) The response from RVLM was elicited at a lower frequency. 2) Regional vascular resistance changes were different, i.e., electrical stimulation of NA increased vascular resistance in hindquarters much more than the renal and mesenteric beds. In contrast, electrical and chemical stimulation of RVLM produced a more prominent effect on the renal vascular bed. 3) Bradycardia was elicited from NA at lower current intensity. 4) Glutamate produced bradycardia only when injected into NA. Studies in rats with sinoaortic deafferentation showed that bradycardic response to activation of NA was only partly reflex in origin. We conclude that 1) NA and RVLM control sympathetic outflow to regional vascular beds differentially and 2) the NA region involves parasympathetic control of heart rate and sympathetic control of arterial pressure.

Mechanism of action of vasoconstrictor responses to atriopeptin II in conscious SHR

1985 ◽  
Vol 249 (6) ◽  
pp. R781-R786 ◽  
Author(s):  
R. W. Lappe ◽  
J. A. Todt ◽  
R. L. Wendt
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Sympathetic Nerves ◽  
Spontaneously Hypertensive ◽  
Regional Vascular Resistance ◽  
6 Hydroxydopamine ◽  
Renal Vascular ◽  
Renal Sympathetic

Previous studies have demonstrated that infusion of synthetic atriopeptin II (AP II) lowered arterial pressure, reduced regional blood flow, and increased total peripheral and regional vascular resistances in conscious spontaneously hypertensive rats (SHR). This study was designed to examine the mechanism(s) involved in regional vasoconstrictor responses to AP II. In these experiments, hemodynamic actions of AP II were examined in control, 6-hydroxydopamine-treated (chemically sympathectomized), and renal-denervated groups of instrumented conscious SHR. Infusion of AP II (1 microgram X kg-1 X min-1) caused similar reductions in mean arterial pressure in control (-22 +/- 2 mmHg), chemically sympathectomized (-23 +/- 2 mmHg), and renal-denervated (-23 +/- 3 mmHg) SHR. In control SHR, AP II infusion reduced renal (-20 +/- 3%), mesenteric (-26 +/- 2%), and hindquarters (-18 +/- 10%) blood flow and increased regional vascular resistance in all three beds. Chemical sympathectomy prevented the fall in renal blood flow (RBF) and significantly abolished the regional vasoconstrictor responses to AP II infusion. In unilateral renal-denervated groups of SHR, AP II reduced renal vascular resistance (RVR) -11 +/- 3% but failed to alter RBF (-3 +/- 1%) in denervated kidneys. In contrast, RVR increased (20 +/- 7%) and RBF was significantly reduced (-29 +/- 3%) in contralateral-innervated kidneys. This study demonstrated that chemical or surgical destruction of renal sympathetic nerves abolished AP II-induced increases in RVR. These data further indicate that in conscious SHR the regional vasoconstrictor responses to AP II infusion appear to be mediated by increases in sympathetic tone rather than through direct vascular actions of AP II.

scholarly journals Evaluation of Tpeak–Tend and QT intervals in Chagas’ Disease, Chronic Phase and Normal Electrocardiogram

2020 ◽  
Vol 32 (4) ◽  
pp. 230-235
Author(s):  
Abilio Augusto Fragata Filho ◽  
Claudia da Silva Fragata ◽  
Angela Maria Lourenço ◽  
Cristiane Castro Faccini ◽  
João Ítalo Dias França
Keyword(s):  
Heart Rate ◽  
Chagas Disease ◽  
Qt Interval ◽  
Statistical Significance ◽  
Chronic Phase ◽  
Qtc Interval ◽  
Mean Values ◽  
Qt Intervals ◽  
Relationship Of ◽  
The Relationship

Introduction: Chagas’ disease lacks elements to predict which carriers will evolve into cardiac form and which will remain in undetermined form. Objective: To evaluate the relationship between electrocardiographic evolution and Tpeak–Tend and QT intervals, both corrected for heart rate, in chagasic patients with normal initial electrocardiogram. Method: Chagasic patients admitted to the institution until 2002 were retrospectively evaluated, and the electrocardiogram was normal at the first consultation. The Tpeak–Tend and QT intervals were measured in milliseconds at the V2 and V5 derivations, with the mean values corrected for heart rate (Bazett). The relationship of these values with the electrocardiographic evolution of the individuals was analyzed, considering the gender, time of evolution and whether they received benznidazole or not. Results: The corrected Tpeak–Tend interval showed no statistical significance among those who maintained or not normal electrocardiogram. The corrected QT interval, the treatment with benznidazole and the time of evolution showed significance for the maintenance of normal electrocardiogram. In the multivariate evaluation, treatment with benznidazole, the QTc interval and the time of evolution were independent variables for the maintenance of normal electrocardiogram. Conclusion: The Tpeak–Tend interval showed no predictor of electrocardiographic evolution. The increased QT interval favored changes.

scholarly journals Renal function and histology after acute hemorrhage in rats under dexmedetomidine action

2007 ◽  
Vol 22 (4) ◽  
pp. 291-298 ◽  
Author(s):  
Marco Aurelio Marangoni ◽  
Alex Hausch ◽  
Pedro Thadeu Galvão Vianna ◽  
José Reinaldo Cerqueira Braz ◽  
Rosa Marlene Viero ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Renal Function ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Filtration Fraction ◽  
Acute Hemorrhage ◽  
Renal Vascular

PURPOSE: About 50 % of indications for dialysis in acute renal failure are related to problems originated during the perioperative period. Intraoperative hemodynamic changes lead to renal vasoconstriction and hypoperfusion. Previous studies have not defined the dexmedetomidine renal role in hemorrhage situations. This study evaluated the effect of dexmedetomidine on renal function and histology after acute hemorrhage in rats. METHODS: Covered study with 20 Wistars rats, anesthetized with sodium pentobarbital, 50 mg. kg-1, intraperitoneal, randomized into 2 groups submitted to 30% volemia bleeding: DG - iv dexmedetomidine, 3 µg. kg-1 (10 min) and continuous infusion - 3 µg. kg-1. h-1; CG - pentobarbital. For renal clearance estimative, sodium p-aminohippurate and iothalamate were administered. Studied attributes: heart rate, mean arterial pressure, rectal temperature, hematocrit, iothalamate and p-aminohippurate clearance, filtration fraction, renal blood flow, renal vascular resistance, and histological evaluations of the kidneys. RESULTS: DG showed smaller values of heart rate, mean arterial pressure, and renal vascular resistance, but iothalamate clearance and filtration fraction values were higher. There was similarity in p-aminohippurate clearance and renal blood flow. Both groups had histological changes ischemia-like, but dexmedetomidine determined higher tubular dilatation scores. CONCLUSION: In rats, after acute hemorrhage, dexmedetomidine determined better renal function, but higher tubular dilation scores.

Role of pressor mechanisms from the NTS and CVLM in control of arterial pressure

2005 ◽  
Vol 289 (5) ◽  
pp. R1416-R1425 ◽  
Author(s):  
Thiago Santos Moreira ◽  
Monica Akemi Sato ◽  
Ana Carolina Thomaz Takakura ◽  
José Vanderlei Menani ◽  
Eduardo Colombari
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Kynurenic Acid ◽  
Ventrolateral Medulla ◽  
Solitary Tract ◽  
Baseline Levels ◽  
Renal Vascular

In the present study, we investigated the effects of inhibition of the caudal ventrolateral medulla (CVLM) with the GABAA agonist muscimol combined with the blockade of glutamatergic mechanism in the nucleus of the solitary tract (NTS) with kynurenic acid (kyn) on mean arterial pressure (MAP), heart rate (HR), and regional vascular resistances. In male Holtzman rats anesthetized intravenously with urethane/chloralose, bilateral injections of muscimol (120 pmol) into the CVLM or bilateral injections of kyn (2.7 nmol) into the NTS alone increased MAP to 186 ± 11 and to 142 ± 6 mmHg, respectively, vs. control: 105 ± 4 mmHg; HR to 407 ± 15 and to 412 ± 18 beats per minute (bpm), respectively, vs. control: 352 ± 12 bpm; and renal, mesenteric and hindquarter vascular resistances. However, in rats with the CVLM bilaterally blocked by muscimol, additional injections of kyn into the NTS reduced MAP to 88 ± 5 mmHg and mesenteric and hindquarter vascular resistances below control baseline levels. Moreover, in rats with the glutamatergic mechanisms of the NTS blocked by bilateral injections of kyn, additional injections of muscimol into the CVLM also reduced MAP to 92 ± 2 mmHg and mesenteric and hindquarter vascular resistances below control baseline levels. Simultaneous blockade of NTS and CVLM did not modify the increase in HR but also abolished the increase in renal vascular resistance produced by each treatment alone. The results suggest that important pressor mechanisms arise from the NTS and CVLM to control vascular resistance and arterial pressure under the conditions of the present study.

scholarly journals Centrally acting cholecystokinin induces depressor circulatory effects in haemorrhage-shocked rats

2021 ◽  
Vol 75 ◽  
pp. 18-23
Author(s):  
Karolina Jasikowska ◽  
Magdalena Zając ◽  
Jerzy Jochem
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Renal Vascular Resistance ◽  
Circulatory Effects ◽  
Renal Vascular ◽  
Mesenteric Vascular Resistance

WstępCholecystokinina (CCK) należy do hormonów peptydowych układu pokarmowego regulujących trawienie lipidów i białek, a ponadto jest ośrodkowym neurotransmiterem/neuromodulatorem. Po podaniu dożylnym wywołuje efekt resuscytacyjny u szczurów we wstrząsie krwotocznym. Ze względu na fakt, iż CCK może wpływać bezpośrednio i pośrednio na czynność ośrodka sercowo-naczyniowego, celem pracy było zbadanie działania pochodnej siarczanowej oktapeptydu CCK (CCK-8) podawanej do komory bocznej mózgu (<i>intracerebroventricularly</i> – icv) w fazie hamowania czynności układu współczulnego we wstrząsie krwotocznym.Materiał i metodyBadania przeprowadzono u samców szczurów szczepu Wistar w znieczuleniu ogólnym (ketamina [100 mg/kg]/ksylazyna [10 mg/kg]), u których wywołano nieodwracalny wstrząs krwotoczny (0% przeżycia 2 h) ze średnim ciśnieniem tętniczym (<i>mean arterial pressure</i> – MAP) 20–25 mmHg. W 5 min krytycznej hipotensji szczurom podawano icv CCK-8 (5, 15 nmol) lub 0,9% roztwór NaCl (5 μl).WynikiKrwotok prowadził do obniżenia ciśnienia tętna (<i>pulse pressu</i>re – PP), częstości rytmu serca (<i>heart rate</i> – HR) oraz wzrostu nerkowego (<i>renal vascular resistance</i> – RVR) i krezkowego oporu naczyniowego (<i>mesenteric vascular resistance</i> – MVR). W grupie kontrolnej nie stwierdzono wzrostu badanych parametrów układu krążenia, a średni czas przeżycia wynosił 32,5 ± 5,1 min. CCK-8 wywoływała zależne od dawki spadki MAP, PP i HR ze wzrostem RVR i MVR, a także skracała czas przeżycia w porównaniu ze zwierzętami kontrolnymi.WnioskiOśrodkowo działająca CCK-8 wywołuje działanie depresyjne na układ krążenia u szczurów we wstrząsie krwotocznym.

scholarly journals Emotional reactions of horses and trainers during natural method training / Reakcje emocjonalne koni i trenerów podczas treningu metodami naturalnymi

2013 ◽  
Vol 13 (2) ◽  
pp. 263-273 ◽  
Author(s):  
Iwona Janczarek ◽  
Witold Kędzierski ◽  
Anna Stachurska ◽  
Izabela Wilk
Keyword(s):  
Heart Rate ◽  
Emotional Reactions ◽  
Point Of View ◽  
Emotional Status ◽  
Mean Values ◽  
Training Cycle ◽  
Relationship Of ◽  
The Relationship ◽  
Pearson Correlations ◽  
Natural Method

Abstract The first aim of the present study was to evaluate whether the trainer factor and the sex of the horse affect the heart rate (HR) of the trainer-horse pair. The second aim was to estimate the level of the trainer-horse pair’s emotions and to find the relationship of the HR between the trainer and the horse during the preliminary, natural-method training. The animals used in the study were 40 three-year-old purebred Arabian horses trained by two trainers from the Silversand Horsemanship School. Each trainer worked with 20 randomly selected horses, equally grouped by sex. The study was carried out during the first day of the training cycle. The aim was to have a horse accept a rider. The following items were subject to analysis: deconcentration, concentration, desensitizing, putting on the lungeing surcingle, and saddling. The emotional status of the horses and the trainers was evaluated based on HR variations which were measured by applying Polar S810 telemetric devices. The device produced continuous measurements with readings every 60 seconds. Two-factor analysis of variance and Pearson correlations were determined with the use of SAS software. Significance of differences between mean values was verified using Tukey’s test. The results obtained revealed that the sex of the trained horses was not an important factor in the evaluation of trainer’s emotions, despite the fact that fillies were characterized as having a more uniform HR. The trainer is very responsible for the emotions of a trained horse, especially at the beginning of training and during saddling. From a trainer’s point of view, it is important to complete the horse concentration task as quickly as possible. The lack of an emotional relationship in the trainer-horse pair during some training elements, suggests that it is not only the trainer’s experience, but mainly the trainer’s personality that determines the probable success in naturalmethod work.

Hypotensive and Regional Haemodynamic Effects of Exercise, Fasted and after Food, in Human Sympathetic Denervation

1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Superior Mesenteric Artery ◽  
Vascular Resistance ◽  
Mesenteric Artery ◽  
Autonomic Failure ◽  
Sympathetic Denervation ◽  
Stroke Distance

1. In human sympathetic denervation due to primary autonomic failure, food and exercise in combination may produce a cumulative blood pressure lowering effect due to simultaneous splanchnic and skeletal muscle dilatation unopposed by corrective cardiovascular reflexes. We studied 12 patients with autonomic failure during and after 9 min of supine exercise, when fasted and after a liquid meal. Standing blood pressure was also measured before and after exercise. 2. When fasted, blood pressure fell during exercise from 162 ± 7/92 ± 4 to 129 ± 9/70 ± 5 mmHg (mean arterial pressure by 22 ± 5%), P < 0.0005. After the meal, blood pressure fell from 159 ± 8/88 ± 6 to 129 ± 6/70 ± 4 mmHg (mean arterial pressure by 22 ± 3%), P < 0.0001, and further during exercise to 123 ± 6/61 ± 3 mmHg (mean arterial pressure by 9 ± 3%), P < 0.01. The stroke distance—heart rate product, an index of cardiac output, did not change after the meal. During exercise, changes in the stroke distance—heart rate product were greater when fasted. 3. Resting forearm and calf vascular resistance were higher when fasted. Calf vascular resistance fell further after exercise when fasted. Resting superior mesenteric artery vascular resistance was lower when fed; 0.19 ± 0.02 compared with 032 ± 0.06, P < 0.05. After exercise, superior mesenteric artery vascular resistance had risen by 82%, to 0.53 ± 0.12, P < 0.05 (fasted) and by 47%, to 0.29 ± 0.05, P < 0.05 (fed). 4. On standing, absolute levels of blood pressure were higher when fasted [83 ± 7/52 ± 7 compared with 71 ± 2/41 ± 3 (fed), each P < 0.05]. Subjects were more symptomatic on standing post-exercise when fed. 5. In human sympathetic denervation, exercise in the fed state lowered blood pressure further than when fasted and worsened symptoms of postural hypotension.

Energy expenditure by elite midget male ice hockey players in small-sided games

2017 ◽  
Vol 12 (4) ◽  
pp. 504-513 ◽  
Author(s):  
Charles-Mathieu Lachaume ◽  
François Trudeau ◽  
Jean Lemoyne
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Ice Hockey ◽  
Training Method ◽  
Hockey Players ◽  
Treadmill Testing ◽  
Effective Training ◽  
Relationship Of ◽  
The Relationship

The purpose of this study was to investigate the energy expenditure and heart rate responses elicited in elite male midget ice hockey players during small-sided games. Nine players (aged 15.89 ± 0.33 years) participated in the study. Maximal progressive treadmill testing in the laboratory measured the relationship of oxygen consumption ([Formula: see text]) to heart rate before on-ice assessments of heart rate during six different small-sided games: 1v1, 2v2, 2v2 with support player, 3v3 with support player, 3v3 with transitions, and 4v4 with two support players. Heart rate was recorded continuously in each game. 3v3 T small-sided game was the most intense for all four intensity markers. All six small-sided games reached 89% HRmax or more with heart rate peaks in active effort repetition. These findings demonstrate that such small-sided games are considered as high intensity games and are an effective training method for ice hockey players.

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