scholarly journals Sulprostone-Induced Gastric Dysrhythmia in the Ferret: Conventional and Advanced Analytical Approaches

2021 ◽  
Vol 11 ◽  
Author(s):  
Zengbing Lu ◽  
Yu Zhou ◽  
Longlong Tu ◽  
Sze Wa Chan ◽  
Man P. Ngan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Analytical Techniques ◽  
Dominant Frequency ◽  
Fluctuation Analysis ◽  
Prostaglandin E ◽  
Myoelectric Activity ◽  
Core Body ◽  
Analytical Approaches

Nausea and emesis resulting from disease or drug treatment may be associated with disrupted gastric myoelectric activity (GMA). Conventional analytical techniques can determine the relative degrees of brady-, normo-, and tachygastric power, but lose information relative to the basic slow wave shape. The aim of the present study was to investigate the application of advanced analytical techniques in the analysis of disrupted GMA recorded after administration of sulprostone, a prostaglandin E3/1 agonist, in ferrets. Ferrets were implanted with radiotelemetry devices to record GMA, blood pressure, heart rate (HR) and core body temperature 1 week before the administration of sulprostone (30 μg/kg) or vehicle (saline, 0.5 mL/kg). GMA was initially analyzed using fast Fourier transformations (FFTs) and a conventional power partitioning. Detrended fluctuation analysis (DFA) was also applied to the GMA recordings to reveal information relative to the fluctuation of signals around local trends. Sample entropy (SampEn) analysis was used for examining the regularity of signals. Conventional signal processing techniques revealed that sulprostone increased the dominant frequency (DF) of slow waves, with an increase in the percentage power of the tachygastric range and a decrease in the percentage power of the normogastric range. DFA revealed that sulprostone decreased the fluctuation function, indicative of a loss of the variability of GMA fluctuations around local trends. Sulprostone increased SampEn values, indicating a loss of regularity in the GMA data. Behaviorally, sulprostone induced emesis and caused defecation. It also increased blood pressure and elevated HR, with an associated decrease in HR variability (HRV). Further analysis of HRV revealed a decrease in both low-frequency (LF) and high-frequency (HF) components, with an overall increase in the LF/HF ratio. Sulprostone did not affect core body temperature. In conclusion, DFA and SampEn permit a detailed analysis of GMA, which is necessary to understand the action of sulprostone to modulate gastric function. The action to decrease HRV and increase the LF/HF ratio may be consistent with a shift toward sympathetic nervous system dominance, commonly seen during nausea.

“On-” and “off-” cells in the rostral ventromedial medulla of rats held in thermoneutral conditions: are they involved in thermoregulation?

2014 ◽  
Vol 112 (9) ◽  
pp. 2199-2217 ◽  
Author(s):  
Nabil El Bitar ◽  
Bernard Pollin ◽  
Daniel Le Bars
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Rostral Ventromedial Medulla ◽  
Sequence Of Events ◽  
Ventromedial Medulla ◽  
Cyclic Variations ◽  
On And Off Cells ◽  
Core Body

In thermal neutral condition, rats display cyclic variations of the vasomotion of the tail and paws, synchronized with fluctuations of blood pressure, heart rate, and core body temperature. “On-” and “off-” cells located in the rostral ventromedial medulla, a cerebral structure implicated in somatic sympathetic drive, 1) exhibit similar spontaneous cyclic activities in antiphase and 2) are activated and inhibited by thermal nociceptive stimuli, respectively. We aimed at evaluating the implication of such neurons in autonomic regulation by establishing correlations between their firing and blood pressure, heart rate, and skin and core body temperature variations. When, during a cycle, a relative high core body temperature was reached, the on-cells were activated and within half a minute, the off-cells and blood pressure were depressed, followed by heart rate depression within a further minute; vasodilatation of the tail followed invariably within ∼3 min, often completed with vasodilatation of hind paws. The outcome was an increased heat loss that lessened the core body temperature. When the decrease of core body temperature achieved a few tenths of degrees, sympathetic activation switches off and converse variations occurred, providing cycles of three to seven periods/h. On- and off-cell activities were correlated with inhibition and activation of the sympathetic system, respectively. The temporal sequence of events was as follows: core body temperature → on-cell → off-cell ∼ blood pressure → heart rate → skin temperature → core body temperature. The function of on- and off-cells in nociception should be reexamined, taking into account their correlation with autonomic regulations.

scholarly journals Effects of Pre-cooling and Per-cooling on Neural, Physiological, and Functional Responses in Active Young Girls

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Seyedeh Somayeh Razavi ◽  
Amirabbas Monazzami ◽  
Zahra Nikosefat
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Temperature ◽  
Repeated Measures ◽  
Blood Pressure Monitoring ◽  
Core Body Temperature ◽  
Control Group ◽  
Functional Responses ◽  
Young Girls ◽  
Core Body

Background: Stressful environments, especially air temperature, have significant effects on human physiological responses to physical activity. Objectives: The current study aimed to determine the effects of pre-cooling and per-cooling on neural, physiological, and functional responses in active young girls. Methods: Twelve active girls (age 24.6 ± 1.4, weight 55.46 ± 8.18, height 165.1 ± 5.91) were tested in three separate sessions with intervals of three days between each session. All subjects performed the Balke test in three groups either without an ice vest (control and pre-cooling) or with an ice vest (per-cooling) in each session, randomly. Pre-cooling was applied with an ice vest for 30 min just before the test, while per-cooling was used with an ice vest from the beginning of the test to exhaustion. A Buerer FT-70 digital thermometer, polar-FT60 heart rate monitoring, Microlife blood pressure monitoring, and ELISA technique were used to measure core body temperature, heart rate, blood pressure, dopamine, cortisol, and lactate dehydrogenase, respectively. Two-way repeated-measures ANOVA was applied to analyze the data with a confidence interval of 95%. Results: The heart rate and core body temperature significantly decreased at the end of the test in the pre-cooling and per-cooling groups (P < 0.05). There was an improved performance with an increase in Tmax in the per-cooling group compared to the control group (P < 0.05) although this difference was not significant in the pre-cooling group compared to the control group (P > 0.05). Dopamine, cortisol, and lactate dehydrogenize increased in the groups in comparison with the pretest (P < 0.05) even though these differences were not significant in the comparison between the groups (P > 0.05). Conclusion: The findings suggest that pre-cooling and per-cooling could be used as a beneficial method to improve performance due to not only a decrease in core body temperature and heart rate but also an increase in the level of dopamine and cortisol. Moreover, per-cooling was more effective than pre-cooling to increase performance.

Role of the hypothalamic PVN in the reflex reduction in mesenteric blood flow elicited by hyperthermia

2008 ◽  
Vol 295 (6) ◽  
pp. R1874-R1881 ◽  
Author(s):  
Feng Chen ◽  
Melissa Dworak ◽  
Yuliang Wang ◽  
Joo Lee Cham ◽  
Emilio Badoer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Separate Group ◽  
Control Group ◽  
Mesenteric Blood Flow ◽  
Significant Difference ◽  
Core Body

The hypothalamic paraventricular nucleus (PVN) is an important integrative center in the brain. In the present study, we investigated whether the PVN is a key region in the mesenteric vasoconstriction that normally accompanies an increase in core body temperature. Anesthetized rats were monitored for blood pressure, heart rate, mesenteric blood flow, and vascular conductance. In control rats, elevation of core body temperature to 41°C had no significant effect on blood pressure, increased heart rate, and reduced mesenteric blood flow by 21%. In a separate group of rats, muscimol was microinjected bilaterally (1 nmol/side) into the PVN. Compared with the control group, there was no significant difference in the blood pressure and heart rate responses elicited by the increase in core body temperature. In contrast to control animals, however, mesenteric blood flow did not fall in the muscimol-treated rats in response to the elevation in core body temperature. In a separate group, in which muscimol was microinjected into regions outside the PVN, elevating core body temperature elicited the normal reduction in mesenteric blood flow. The results suggest that the PVN may play a key role in the reflex decrease in mesenteric blood flow elicited by hyperthermia.

scholarly journals Pharmacological Suppression of Endogenous Glucocorticoid Synthesis Attenuated Blood Pressure and Heart Rate Response to Acute Restraint in Wistar Rats

2020 ◽  
pp. 415-426
Author(s):  
M BENCZE ◽  
A VAVŘÍNOVÁ ◽  
J ZICHA ◽  
M BEHULIAK
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Temperature ◽  
Cardiovascular System ◽  
Wistar Rats ◽  
Cardiovascular Response ◽  
Core Body Temperature ◽  
Plasma Renin ◽  
Adequate Response ◽  
Core Body

Glucocorticoids (GCS) are known to modulate cardiovascular response during stress conditions. The present study was aimed to test the hypothesis that permissive and/or stimulating effect of GCs is essential for the maintenance of peripheral vascular resistance and for the adequate response of cardiovascular system to stressor exposure. The effects of acute pharmacological adrenalectomy (PhADX) on humoral and cardiovascular parameters were studied in adult Wistar rats under the basal conditions and during the acute restraint stress. Acute PhADX was performed by the administration of metyrapone and aminoglutethimide (100 mg/kg s.c. of each drug) resulting in a suppression of endogenous glucocorticoid synthesis. Blood pressure (BP), heart rate (HR) and core body temperature were measured using radiotelemetry. BP responses to administration of vasoactive agents were determined in pentobarbital-anesthetized animals. PhADX considerably attenuated stress-induced increase of BP, HR and core body temperature. PhADX did not abolish BP and HR lowering effects of ganglionic blocker pentolinium indicating preserved sympathetic function in PhADX rats. BP response to exogenous norepinephrine administration was attenuated in PhADX rats, suggesting reduced sensitivity of cardiovascular system. Suppression of corticosterone synthesis by PhADX increased basal plasma levels of ACTH, aldosterone and plasma renin activity in unstressed animals but there was no further increase of these hormones following stressor exposure. In conclusion, PhADX attenuated stress-induced rise of blood pressure, heart rate and core body temperature indicating an important permissive and/or stimulating role of glucocorticoids in the maintenance of the adequate response of cardiovascular system and thermoregulation to several stimuli including acute exposure to stressor.

Abstract P199: Circadian Contributions To Blood Pressure Variation Under Constant Conditions

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Gabrielle F Gloston ◽  
Annie E Ensor ◽  
Samarth Patel ◽  
Rebecca Williams ◽  
Courtney M Peterson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Temperature ◽  
Circadian Clock ◽  
Environmental Changes ◽  
Core Body Temperature ◽  
Circadian System ◽  
External Factors ◽  
Future Research ◽  
Physiological Processes ◽  
Core Body

The circadian clock is an endogenous biological timekeeper that responds to environmental changes and governs various physiological processes over a 24-hour cycle. Blood pressure (BP) variation is thought to be controlled by the circadian clock, but few studies have examined circadian control of BP in humans. Moreover, it is unknown whether nighttime BP dipping is driven by the circadian system or by external factors. We investigated whether the circadian system drives 24-hour rhythms in BP, including nighttime BP dipping, using a 30-hour constant routine (CR) protocol. The CR protocol controls for external factors, allowing circadian rhythms to be isolated and measured, by having participants lie in a semi-recumbent posture in dim light (<10 lux) at a constant temperature, consume isocaloric snacks every 2 hours, and maintain wakefulness. To measure the BP rhythm, ambulatory BP was measured every 30 minutes (SpaceLabs 90227), and to measure the central circadian rhythm, core body temperature was measured every 10 seconds using an ingestible, wireless sensor (HQInc Core Body Temperature Wireless Data Record and Sensor). To date, 17 normotensive African American participants (13 females and 4 males), with a mean age of 37 (± 11.3) years and body mass index (BMI) of 32.5 kg/m 2 , have completed the study. Approximately 59% of participants (10 of 17) had non-dipping systolic BP at screening, defined as a <10% decrease in mean systolic BP from daytime to nighttime. Under constant conditions, 94% of participants (16 of 17) had a non-dipping BP phenotype. Median systolic BP dipping was 0.8% for females and 2.2% for males. There was a robust rhythm in participants’ core body temperature but not BP, suggesting that the circadian clock may not contribute substantially to a nighttime decrease in BP in normotensive African Americans. Instead, the non-dipping BP phenotype is likely more so a result of behavioral and/or physiological sleep-related processes. Future research and interventions for non-dipping BP may need to target these underlying behavioral and physiological processes.

Abstract 412: A Unique Telemetric Method for Long-term Measurement of Blood Pressures and Core Body Temperature in Hypertensive and Normotensive Non-human Primates

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Jeffrey L Osborn ◽  
Megan K Rhoads ◽  
Jason A Collett ◽  
Amy Beierschmitt ◽  
John Dascanio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Essential Hypertension ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Pressure Sensors ◽  
Primate Model ◽  
Cardiovascular Assessment ◽  
Core Body ◽  
Human Primate

A non-human primate model of essential hypertension has unequivocal potential for understanding mechanisms of disease but requires a unique method for telemetric blood pressure measurement in animals living within a habituated natural environment. We have now identified a unique non-human primate model of spontaneous, essential hypertension in Chlorocebus aethiops sabaeus, the African Green, or vervet, monkey. Using forearm plethysmography under light ketamine sedation (~15mg/kg), adult vervets were categorized as hypertensive (HT; SBP >140mmHg), borderline hypertensive (BHT; 120mmHg < SBP < 140mmHg), or normotensive (NT; SBP < 120 mmHg). Of the 168 males phenotyped, 32% (53 of 168) were HT (average SBP = 168.79±3.29mmHg), 27% (45 of 168) were BHT (average SBP = 129.58±0.88mmHg), and 41% (70 of 168) were NT (average SBP = 100.21±1.65mmHg). Stellar Telemetry solid-state pressure sensors were surgically implanted into the abdominal aorta of feral, male monkeys (Chlorocebus sabaeus aethiops). SBP, diastolic (DBP) and mean (MBP) arterial pressures, core body temperature and heart rate were determined using different data acquisition parameters to assess system precision and reliability in this physically active non-human primate with spontaneous essential hypertension. All animals were pre-phenotyped for blood pressure using forearm plethysmography under light ketamine anesthesia. Different recording parameters (n=4) yielded consistent BPs, in normotensive (MBP=104±4.35 mmHg) and hypertensive (MBP=126±7.57 mmHg) animals. Ultrasonographic examination documented effective sensor placement directly within the vessel lumen. Post implant necropsy revealed no sensor induced blood pathologies. Conscious, telemetered SBPs were consistent with those of monkeys measured using plethysmography. This model of hypertension in an Old World, non-human primate is translational to human essential hypertension and allows for new directions in a genetically similar species. The use of the Stellar Telemetry system is ideal for monitoring conscious blood pressure, heart rate and body temperature in active primates allowing for cardiovascular assessment during natural social interactions and species specific behaviors.

scholarly journals Heat Exposure and Physiological Changes among Cooks

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Siti Marwanis Anua ◽  
Mohd Nizamuddin Ismail ◽  
Mohd Amierul Aieman Mohd Nordin ◽  
Faridah Naim ◽  
Nurul Ainun Hamzah ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Temperature ◽  
Core Body Temperature ◽  
Sampling Site ◽  
Heat Exposure ◽  
Physiological Changes ◽  
Sweat Production ◽  
Core Body ◽  
Post Shift

Cooks who are exposed to heat produced from stoves when working in the kitchen are at risk of thermal stress and heat-related illness. Physiological changes such as increased heart rate, sweat production and blood pressure may also affect them. This study aimed to determine the area heat exposure levels and physiological changes including core body temperature, blood pressure and heart rate during pre-, mid- and post-shift among cooks and its association, and to compare the mean difference of physiological changes between the shifts. This cross-sectional study utilised the purposive sampling method and recruited 30 cooks from food stalls and cafeterias in Kelantan. Area heat measurements were collected from 14 sites (7 inside and 7 outside the USM Health Campus). Wet-bulb Globe Temperature (WBGT) monitor was mounted on a tripod at 1.1 m height near the source of heat for 8 hours. The core body temperature, blood pressure, and heart rate were taken three times per day during pre-, mid- and post-shift for physiological changes measurement. Respondents’ personal information, health history, work description, and symptoms of heat-related illness were collected using a questionnaire. The overall WBGT area levels at each sampling site were homogeneously distributed. There was significant increase in core body temperature and heart rate from pre-shift to post-shift. However, there was no significant correlation (p>0.05) between heat exposure (WBGT index) established with the physiological changes. This may suggest that the increase in core body temperature and heart rate might be attributed to other factors and needed further investigation.

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