scholarly journals Transient hypertension and sustained tachycardia in mice housed individually in metabolism cages

2009 ◽  
pp. 69-75 ◽  
Author(s):  
CC Hoppe ◽  
KM Moritz ◽  
SM Fitzgerald ◽  
JF Bertram ◽  
RG Evans

The novel environment of a metabolic cage can be stressful for rodents, but few studies have attempted to quantify this stressresponse. Therefore, we determined the effects on mean arterial pressure (MAP) and heart rate (HR), of placing mice of both sexes in metabolism cages for 2 days. After surgical implantation of a carotid artery catheter mice recovered individually in standard cages for 5 days. Mice then spent 2 days in metabolism cages. MAP and HR were monitored in the standard cage on Day 5 and in metabolism cages on Days 6-7. MAP increased by 18±3 and 22±4 %, while HR increased by 27±4 and 27±6 %, in males and females, respectively, during the first hours after cage switch. MAP decreased to baseline in the fourth and eighth h following metabolism cage switch in males and females, respectively. However, HR remained significantly elevated in both sexes during the entire two-day period in metabolism cages. Females had lower MAP than males both pre- and postmetabolism cage switch, but there were no sex differences in HR. These results demonstrate sustained changes in cardiovascular function when mice are housed in metabolism cages, which could potentially affect renal function.

2020 ◽  
Vol 319 (1) ◽  
pp. F76-F83
Author(s):  
Shereen M. Hamza ◽  
Xiaohua Huang ◽  
Tayyaba Zehra ◽  
Wenqing Zhuang ◽  
William A. Cupples ◽  
...  

Acutely increased renal venous pressure (RVP) impairs renal function, but the long-term impact is unknown. We investigated whether chronic RVP elevation impairs baseline renal function and prevents exacerbation of renal dysfunction and cardiovascular instability upon further RVP increase. RVP elevation (20–25 mmHg) or sham operation (sham) was performed in rats. After 1 wk ( n = 17) or 3 wk ( n = 22), blood pressure, RVP, renal blood flow (RBF), renal vascular conductance (RVC), and glomerular filtration rate (GFR) were measured at baseline and during superimposed RVP increase. Chronic RVP elevation induced extensive renal venous collateral formation. RVP fell to 6 ± 1 mmHg at 1 wk and 3 ± 1 mmHg at 3 wk. Baseline blood pressure and heart rate were unaltered compared with sham. RBF, RVC, and GFR were reduced at 1 wk but normalized by 3 wk. Upon further RVP increase, the drop in mean arterial pressure was attenuated at 3 wk compared with 1 wk ( P < 0.05), whereas heart rate fell comparably across all groups; the mean arterial pressure-heart rate relationship was disrupted at 1 and 3 wk. RBF fell to a similar degree as sham at 1 wk (−2.3 ± 0.7 vs. −3.9 ± 1.2 mL/min, P = 0.066); however, at 3 wk, this was attenuated compared with sham (−1.5 ± 0.5 vs. −4.2 ± 0.7 mL/min, P < 0.05). The drop in RVC and GFR was attenuated at 1 and 3 wk ( P < 0.05). Thus, chronic RVP elevation induced by partial renal vein ligation elicits extensive renal venous collateral formation, and although baseline renal function is impaired, chronic RVP elevation in this manner induces protective adaptations in kidneys of healthy rats, which attenuates the hemodynamic response to further RVP increase.


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 ◽  
...  

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.


1991 ◽  
Vol 261 (3) ◽  
pp. E395-E401
Author(s):  
T. A. Cudd ◽  
C. E. Wood

The hypothesis that prostaglandin E2 (PGE2) is a circulating mediator of adrenocorticotropic hormone (ACTH) secretion in sheep was tested in conscious adult ewes using 30-min carotid artery infusions of 0, 5, 10, 100, and 500 ng.kg-1. min-1 PGE2 in saline. ACTH, cortisol, and aldosterone were significantly increased during the 500 ng.kg-1.min-1 infusion (166 +/- 61 to 233 +/- 38 pg/ml, 27 +/- 5 to 45 +/- 2 ng/ml, and 52 +/- 11 to 85 +/- 25 pg/ml, respectively). PGE2 infusions of 100 ng.kg-1.min-1 increased ACTH from 104 +/- 31 to 168 +/- 31 pg/ml and cortisol from 18 +/- 5 to 42 +/- 2 ng/ml. PGE2 infusions did not increase arginine vasopressin, plasma renin activity, or hematocrit. Heart rate and mean arterial pressure were minimally but significantly increased during the 500 ng.kg-1.min-1 infusion, from 84.9 +/- 2.8 to 99.3 +/- 5.4 beats/min and 95.5 +/- 1.8 to 101.0 +/- 3.4 mmHg, respectively. In a second study to test whether lower infusion rates of PGE2 increase plasma ACTH in sheep with lower resting hormone concentrations, sheep were infused and sampled through a tether system, preventing any disturbances due to human contact the day of an experiment. For all infusion rates ACTH baselines were less than or equal to 55 +/- 17 pg/ml, and cortisol baselines were less than or equal to 6 +/- 3 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)


2010 ◽  
Vol 299 (4) ◽  
pp. R1114-R1120 ◽  
Author(s):  
Misa Yoshimoto ◽  
Keiko Nagata ◽  
Kenju Miki

The present study was designed to document changes in sympathetic nerve activity and cardiovascular function when conscious rats were challenged with a noise stressor to induce freezing behavior. The potential contribution of the arterial baroreceptors in regulating sympathetic nerve activity and cardiovascular adjustments during the freezing behavior was then examined. Wistar male rats were assigned to sham-operated (SO) and sinoaortic-denervated (SAD) groups and instrumented chronically with electrodes for measurements of renal (RSNA) and lumbar (LSNA) sympathetic nerve activity, electroencephalogram, electromyogram, and electrocardiogram and catheters for measurements of systemic arterial and central venous pressure. Both SO and SAD rats were exposed to 90 dB of white noise for 10 min, causing freezing behavior in both groups. In SO rats, freezing behavior was associated with an immediate and significant ( P < 0.05) increase in RSNA, no changes in LSNA or mean arterial pressure, and a significant ( P < 0.05) decrease in heart rate. SAD attenuated the magnitude of the immediate increase in RSNA and had no influence on the response in LSNA during freezing behavior compared with SO rats. Moreover, in SAD rats, mean arterial pressure increased significantly ( P < 0.05) while heart rate did not change during the freezing behavior. These data indicate that freezing behavior evokes regionally different changes in sympathetic outflows, which may be involved in generating the patterned responses of cardiovascular function to stressful or threatening sensory stimulation. Moreover, it is suggested that the arterial baroreceptors are involved in generating the differential changes in RSNA and LSNA and thus the patterned changes in cardiovascular functions observed during freezing behavior in conscious rats.


2008 ◽  
Vol 108 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Colin Forbes Royse ◽  
David F. L. Liew ◽  
Christine E. Wright ◽  
Alistair G. Royse ◽  
James A. Angus

Background Propofol, sevoflurane, and desflurane may cause hemodynamic compromise during anesthesia and critical care management. The aim of the study was to compare these anesthetics during increased dose and recovery to maintenance level. Methods Anesthetized, open-chest New Zealand White rabbits were used to acquire dose-response curves with sevoflurane, desflurane, and propofol, followed by reduction to baseline infusion. Simultaneous high-fidelity left ventricular pressure and volume data were acquired during caval occlusion with a dual-field conductance catheter inserted via an apical stab. The preload recruitable stroke work and the end-diastolic pressure-volume relationship were used as the primary measures of contractility and diastolic function. Results The time-matched controls were stable over time. Propofol and desflurane but not sevoflurane caused dose-dependent reductions in myocardial contractility, although sevoflurane reduced contractility more at 1 minimal alveolar concentration. All anesthetics reduced mean arterial pressure, and significant recovery occurred for sevoflurane and desflurane but not for propofol. The end-diastolic pressure-volume relationship was increased by sevoflurane. Ejection fraction decreased with sevoflurane only. All anesthetics caused dose-dependent vasodilation, with recovery for desflurane and sevoflurane but not propofol. Heart rate was decreased with propofol without significant recovery. Propofol plasma concentrations remained elevated after dose return to baseline infusion rate, suggestive of distribution compartment saturation. Conclusion All three anesthetics caused dose-dependent decreases in cardiovascular function. Recovery of cardiovascular function occurred rapidly with sevoflurane and desflurane, but persistent depression of contractility, vasodilation, mean arterial pressure, and heart rate occurred with propofol during a 30-min recovery period.


2020 ◽  
Vol 19 ◽  
pp. 153303382097754
Author(s):  
Lihong Zheng ◽  
Juan Zhao ◽  
Likun Zheng ◽  
Shuangfeng Jing ◽  
Xiaoting Wang

Objective: This study aims to investigate the effect of dexmedetomidine on perioperative stress response and immune function in patients with tumors. Methods: Sixty patients who underwent selective radical gastrectomy for cancer were randomly divided into 3 groups: remifentanil group (group R), dexmedetomidine group (group D), and sufentanil group (group S). Remifentanil, dexmedetomidine, and sufentanil were used as general anesthetics. Endotracheal intubation and mechanical ventilation were performed after the spontaneous respiration disappeared. Then, the data were recorded, and blood samples were collected at all time points. Results: The heart rate significantly increased ( P < 0.05) at T1 in group S, and both heart rate and mean arterial pressure significantly increased ( P < 0.05) in group R when compared to group D. The heart rate significantly increased ( P < 0.05) at T2 in group S and group R. Furthermore, the heart rate significantly increased ( P < 0.05) at T3 and T4 in group S and group R. Intra-group comparison: The heart rate at T1–T4 and mean arterial pressure at T1–T4 significantly increased ( P < 0.05) in group S, and the heart rate at T1 and T4, and mean arterial pressure at T2–T4 significantly increased ( P < 0.05) in group R when compared to T0. The serum IL-6, IFN-γ, and β-EP significantly increased ( P < 0.05) at T0’ in group S and group R when compared to group D. Blood glucose, and serum IL-10, IFN-γ, and β-EP significantly increased ( P < 0.05), while IL-18 significantly decreased ( P < 0.05) at T1’ in group S and group R. Conclusion: Continuous infusion of dexmedetomidine in combination with the inhalation of sevoflurane is superior to sevoflurane + remifentanil or sufentanil in patients undergoing tumor surgery.


2018 ◽  
Vol 129 (5) ◽  
pp. 970-988 ◽  
Author(s):  
John J. Savarese ◽  
Hiroshi Sunaga ◽  
Jeff D. McGilvra ◽  
Matthew R. Belmont ◽  
Matthew T. Murrell ◽  
...  

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Structure–activity studies were performed to identify a new neuromuscular blocking agent retaining the ultra-short acting characteristics of gantacurium, including degradation and reversal by l-cysteine, but lacking its histaminoid properties in man. CW 1759-50 has emerged from this program. Methods Adduction of CW 1759-50 with l-cysteine was studied by high-performance liquid chromatography and mass spectrometry. Institutional Animal Care and Use Committee–approved comparisons of CW 1759-50 to gantacurium were performed in rhesus monkeys. ED95 for neuromuscular blockade was established. Spontaneous recovery was compared to reversal by l-cysteine in paired studies of boluses or infusions. In addition, changes in mean arterial pressure and heart rate after very large doses of 15 to 60 × ED95 were compared. Results The half-time of adduction of l-cysteine to CW 1759-50 in vitro was 2.3 min. The ED95 of CW 1759-50 was 0.069 ± 0.02 mg/kg; ED95 of gantacurium was 0.081 ± 0.05 mg/kg (P = 0.006). Duration of action (recovery to 95% twitch height after 98 to 99% blockade) was as follows: CW 1759-50, 8.2 ± 1.5 min; and gantacurium, 7.4 ± 1.9 min; (n = 8 and 9, P = 0.355). Administration of l-cysteine (30 mg/kg) shortened recovery (i.e., induced reversal) from CW 1759-50 after boluses or infusions (P always less than 0.0001). Recovery intervals (5 to 95% twitch) ranged from 6.1 to 6.7 min (and did not differ significantly) after boluses of 0.10 to 0.50 mg/kg, as well as control infusions (P = 0.426 by analysis of variance). Dose ratios comparing changes of 30% in mean arterial pressure or heart rate to ED95 for neuromuscular blockade (ED 30% Δ [mean arterial pressure or heart rate]/ED95) were higher for CW 1759-50 than for gantacurium. Conclusions CW 1759-50, similar to gantacurium, is an ultra-short acting neuromuscular blocking agent, antagonized by l-cysteine, in the monkey. The circulatory effects, however, are much reduced in comparison with gantacurium, suggesting a trial in humans.


1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias

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.


1999 ◽  
Vol 277 (5) ◽  
pp. E920-E926 ◽  
Author(s):  
Joyce M. Richey ◽  
Marilyn Ader ◽  
Donna Moore ◽  
Richard N. Bergman

We set out to examine whether angiotensin-driven hypertension can alter insulin action and whether these changes are reflected as changes in interstitial insulin (the signal to which insulin-sensitive cells respond to increase glucose uptake). To this end, we measured hemodynamic parameters, glucose turnover, and insulin dynamics in both plasma and interstitial fluid (lymph) during hyperinsulinemic euglycemic clamps in anesthetized dogs, with or without simultaneous infusions of angiotensin II (ANG II). Hyperinsulinemia per se failed to alter mean arterial pressure, heart rate, or femoral blood flow. ANG II infusion resulted in increased mean arterial pressure (68 ± 16 to 94 ± 14 mmHg, P < 0.001) with a compensatory decrease in heart rate (110 ± 7 vs. 86 ± 4 mmHg, P < 0.05). Peripheral resistance was significantly increased by ANG II from 0.434 to 0.507 mmHg ⋅ ml−1⋅ min ( P < 0.05). ANG II infusion increased femoral artery blood flow (176 ± 4 to 187 ± 5 ml/min, P < 0.05) and resulted in additional increases in both plasma and lymph insulin (93 ± 20 to 122 ± 13 μU/ml and 30 ± 4 to 45 ± 8 μU/ml, P < 0.05). However, glucose uptake was not significantly altered and actually had a tendency to be lower (5.9 ± 1.2 vs. 5.4 ± 0.7 mg ⋅ kg−1⋅ min−1, P > 0.10). Mimicking of the ANG II-induced hyperinsulinemia resulted in an additional increase in glucose uptake. These data imply that ANG II induces insulin resistance by an effect independent of a reduction in interstitial insulin.


Author(s):  
Sidharth Sraban Routray ◽  
Ramakanta Mohanty

ABSTRACTObjective: During laparoscopic surgeries, pneumoperitoneum can lead to various pathophysiologic changes in the cardiovascular system resulting inhypertension and tachycardia. Search for ideal drug to prevent this hemodynamic response goes on. The aim of our study was to evaluate the effect oforally administered moxonidine in attenuating the hemodynamic responses that occur during the laparoscopic surgeries.Methods: A total of 50 adult acetylsalicylic acid I and II patients scheduled for elective laparoscopic surgeries were selected for this prospectiverandomized double-blinded study. They were randomly allocated into two groups: moxonidine group (M) and placebo group (P). M group receivedoral moxonidine 0.3 mg at 8 pm on the day before surgery and at 8 am on the day of surgery. P group received a placebo at the same timing as that ofthe M group.Results: Following pneumoperitoneum rise in systolic blood pressure (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and heart rate (HR)was higher in P group in comparison to M group which was statistically significant.Conclusion: Significant rise in HR, SBP, DBP, and mean BP was noted in the P group in comparison to moxonidine group. Moxonidine provided betterperioperative hemodynamic stability in patients undergoing laparoscopic surgeries.Keywords: Moxonidine, Stress response, Laparoscopic.


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