Vagal afferent activity increases dynamical dimension of respiration in rats

1991 ◽  
Vol 70 (4) ◽  
pp. 1748-1762 ◽  
Author(s):  
M. P. Sammon ◽  
E. N. Bruce
Keyword(s):  
Intact Animal ◽  
Initial Conditions ◽  
Respiratory Pattern ◽  
Adult Rats ◽  
Correlation Integral ◽  
Before And After ◽  
Respiratory Behavior ◽  
Volume Measurements ◽  
Generator Output ◽  
Low Order

Geometric and numerical techniques from nonlinear dynamics are employed to characterize the respiratory patterns of adult rats. In phase space constructions from volume measurements, the respiratory behavior of the vagotomized rat is seen to be unimodal and periodic, whereas that of the vagi-intact animal is bimodal and sensitive to initial conditions and displays stretching and folding of trajectories. By use of the correlation integral, the dimension and entropy were estimated for the respiratory patterns of five urethan-anesthetized rats (before and after vagotomy) and two awake animals (resting, vagi intact only). The results indicate that the central respiratory pattern of the anesthetized vagotomized rat behaves primarily as a single degree-of-freedom oscillator, which can be moved into a regime of low-order chaos in the presence of feedback from pulmonary stretch receptors, contributing significantly to the variability observed in the respiratory pattern of the vagi-intact animal. A model designed to emulate the Hering-Breuer inflation reflex demonstrates that the inspiration-inhibiting action of the reflex interacting with the oscillator at a critical phase transition is sufficient to drive the central pattern generator output into low-order chaos.

The change of respiratory pattern before and after closing the tracheostoma.

1990 ◽  
Vol 41 (3) ◽  
pp. 202-210
Author(s):  
Isao Uno ◽  
Kenji Oomori ◽  
Akira Miyaso ◽  
Itoji Shibata ◽  
Hiroaki Takahashi
Keyword(s):  
Respiratory Pattern ◽  
Before And After

scholarly journals Dynamics of Space Particles and Spacecrafts Passing by the Atmosphere of the Earth

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Vivian Martins Gomes ◽  
Antonio Fernando Bertachini de Almeida Prado ◽  
Justyna Golebiewska
Keyword(s):  
Initial Conditions ◽  
Equations Of Motion ◽  
Center Of Mass ◽  
The Sun ◽  
Three Body Problem ◽  
The Earth ◽  
Before And After ◽  
Three Body ◽  
Body Energy ◽  
Spacecraft Position

The present research studies the motion of a particle or a spacecraft that comes from an orbit around the Sun, which can be elliptic or hyperbolic, and that makes a passage close enough to the Earth such that it crosses its atmosphere. The idea is to measure the Sun-particle two-body energy before and after this passage in order to verify its variation as a function of the periapsis distance, angle of approach, and velocity at the periapsis of the particle. The full system is formed by the Sun, the Earth, and the particle or the spacecraft. The Sun and the Earth are in circular orbits around their center of mass and the motion is planar for all the bodies involved. The equations of motion consider the restricted circular planar three-body problem with the addition of the atmospheric drag. The initial conditions of the particle or spacecraft (position and velocity) are given at the periapsis of its trajectory around the Earth.

scholarly journals Photogrammetric avalanche volume measurements at Vallée de la Sionne, Switzerland

2001 ◽  
Vol 32 ◽  
pp. 141-146 ◽  
Author(s):  
Juauien Vallet ◽  
Urs Gruber ◽  
François Dufour
Keyword(s):  
Large Scale ◽  
Field Experiments ◽  
Test Site ◽  
Deposition Zone ◽  
Before And After ◽  
Large Scale Field ◽  
Volume Measurements ◽  
Snow Distribution ◽  
The Mean ◽  
The Difference

AbstractDuring winter 1999 three large avalanche events were triggered by explosives at SLF’s avalanche test site, Vallée de la Sionne, canton Valais, Switzerland. One important goal of these large-scale field experiments was to measure the release and deposition volumes of avalanches by photogrammetric methods. In this paper, the photogrammetric measurements of all three avalanches are summarized. For one avalanche event it was possible to realize the whole measuring procedure as planned, and to obtain volume measurements before and after the avalanche triggering In the other two avalanche events, the photographs before the triggering of the avalanche failed. Nevertheless the photographs taken after the avalanche provide valuable information on the fracture depth at the fracture line. The mean fracture depth of the largest avalanche was about 2.10 m, varying between 1 and 3.5 m over a width of > 1000 m. The total volume of the deposition of all three avalanche events was about 1300 000 m3. The deposits are distributed over a length of > 1000 m with depths up to 30 m. The difference between the released and deposited volumes proved that avalanches entrain a large amount of snow along the avalanche track. Furthermore, the snow distribution in the deposition zone provides important information about the behaviour of a dense flowing avalanche in the runout zone.

The bronchodilator test in patients with airway obstruction: the responsiveness of lung function parameters

2021 ◽  
pp. 57-61
Author(s):  
M. I. Chushkin ◽  
L. A. Popova ◽  
E. A. Shergina ◽  
N. L. Karpina
Keyword(s):  
Pulmonary Function ◽  
Airway Obstruction ◽  
Airway Resistance ◽  
Lung Volumes ◽  
Before And After ◽  
Calculated Effect ◽  
Volume Measurements ◽  
The Difference ◽  
Bronchodilator Responsiveness ◽  
Chronic Airway

Interpretation of bronchodilator (BD) test based on reaction of forced expiratory in one second (FEV 1). For assessing bronchodilator responsiveness of lung volumes, airway resistance remains largely unexplored. Therefore, we assessed the response of pulmonary function parameters to BD to reveal the most responsive parameter. 90 patients with chronic airway obstruction (61 male and 29 female; aged 55±11; post-  BD FEV 1 was 63.1+18.3 % predicted) performed spirometry and static lung volume measurements before and after inhalation of BD. We calculated effect size (ES) for each parameter from the difference between two means divided by the standard deviation of baseline score. There was a significant increase both FVC and FEV 1by 8.2 and 12.3 % from baseline (p<0.001). ES were 0.34 for FEV1 and 0.26 for FVC. The ES for lung volumes were from -0.07 (total lung capacity) to -0.31 (residual volume). The ES for sRtot (specific airway resistance) was -0.5 and ES for sGeff (specific effective airway conductance) was 0.95. The parameters of airway resistance and conductance were more responsive for the assessment of pulmonary function changes than spirometry and lung volumes parameters in patients with chronic airway obstruction.

Effect of 2,4-dinitrophenol on the hypometabolic response to hypoxia of conscious adult rats

1997 ◽  
Vol 83 (2) ◽  
pp. 537-542 ◽  
Author(s):  
Chikako Saiki ◽  
Jacopo P. Mortola
Keyword(s):  
Body Temperature ◽  
Oxidative Phosphorylation ◽  
Acute Hypoxia ◽  
Mammalian Species ◽  
Metabolic Effect ◽  
Adult Rats ◽  
Open Flow ◽  
Pharmacological Stimulation ◽  
Before And After ◽  
Mitochondrial Uncoupler

Saiki, Chikako, and Jacopo P. Mortola. Effect of 2,4-dinitrophenol on the hypometabolic response to hypoxia of conscious adult rats. J. Appl. Physiol. 83(2): 537–542, 1997.—During acute hypoxia, a hypometabolic response is commonly observed in many newborn and adult mammalian species. We hypothesized that, if hypoxic hypometabolism were entirely a regulated response with no limitation in O2availability, pharmacological uncoupling of the oxidative phosphorylation should raise O2consumption (V˙o 2) by similar amounts in hypoxia and normoxia. Metabolic, ventilatory, and cardiovascular measurements were collected from conscious rats in air and in hypoxia, both before and after intravenous injection of the mitochondrial uncoupler 2,4-dinitrophenol (DNP). In hypoxia (10% O2 breathing, 60% arterial O2 saturation),V˙o 2, as measured by an open-flow technique, was less than in normoxia (∼80%). Successive DNP injections (6 mg/kg, 4 times) progressively increasedV˙o 2 in both normoxia and hypoxia by similar amounts. Body temperature slightly increased in normoxia, whereas it did not change in hypoxia. The DNP-stimulatedV˙o 2 during hypoxia could even exceed the control normoxic value. A single DNP injection (17 mg/kg iv) had a similar metabolic effect; it also resulted in hypotension and a drop in systemic vascular resistance. We conclude that pharmacological stimulation ofV˙o 2 counteracts theV˙o 2 drop determined by hypoxia and stimulates V˙o 2not dissimilarly from normoxia. Hypoxic hypometabolism is likely to reflect a regulated process of depression of thermogenesis, with no limitation in cellular O2availability.

scholarly journals Cerebral cortex does not modulate “regulated” decrease in core temperature during hypoxemia in rats

1998 ◽  
Vol 274 (4) ◽  
pp. R1158-R1161
Author(s):  
Evvi-Lynn M. Rollins ◽  
James E. Fewell
Keyword(s):  
Cerebral Cortex ◽  
Core Temperature ◽  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Temperature Response ◽  
Sprague Dawley ◽  
Adult Rats ◽  
The Core ◽  
Sprague Dawley Rats ◽  
Before And After

In newborns and adults of a number of species including humans, exposure to acute hypoxemia produces a “regulated” decease in core temperature, the mechanism of which is unknown. Considering that various cortical areas participate in autonomic regulation including thermoregulation, the present experiments were carried out to test the hypothesis that the cerebral cortex plays a role in modulating the regulated decrease in core temperature during acute hypoxemia. This hypothesis was tested by determining the core temperature response to acute hypoxemia in chronically instrumented adult Sprague-Dawley rats before and after cortical spreading depression (i.e., functional decortication) was produced by the local application of potassium chloride to the dura overlying the cerebral hemispheres. There was no effect of cortical spreading depression on baseline core temperature. Core temperature decreased during acute hypoxemia in a similar fashion when the cerebral cortex was intact as well as during functional decortication. Thus our data do not support the hypothesis that the cerebral cortex modulates the regulated decrease in core temperature that occurs in adult rats during acute hypoxemia.

Effect of mannitol on globe and orbital volumes in humans

2018 ◽  
Vol 28 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Adam C. Weber ◽  
Alexander D. Blandford ◽  
Bryan R. Costin ◽  
Julian D. Perry
Keyword(s):  
Volume Change ◽  
Cleveland Clinic ◽  
Retrospective Chart Review ◽  
Consecutive Series ◽  
Orbital Volume ◽  
Computed Tomographic ◽  
Before And After ◽  
Pressure Lowering ◽  
Volume Measurements

Purpose: To determine the effect of intravenous mannitol on globe and orbital volumes. Methods: Retrospective chart review of a consecutive series of Cleveland Clinic Neurosurgical Intensive Care Unit patients who underwent computed tomographic imaging before and after intravenous mannitol administration. Volume measurements were performed according to a previously described technique by averaging axial image areas. Measurements before and after mannitol administration were compared using paired t-test. Results: Fourteen patients (28 eyes) met inclusion criteria. Average globe volume decreased 186 mm3 (-2.5%, p = 0.02) after mannitol administration, while average orbital volume increased 353 mm3 (+3.5%, p = 0.04). Average globe volume change for subjects with follow-up scan less than 4.7 hours (mean 1.9 hours; range 0.2-4.5 hours) after mannitol administration was -125 mm3 (-1.7%, p = 0.24) and average orbital volume change was +458 mm3 (+5.1%, p = 0.11). Average globe volume change after mannitol administration for those with follow-up more than 4.7 hours (average 13.9 hours, range 4.9-24.7 hours) was -246 mm3 (-3.3%, p = 0.05) and orbital volume change was +248 mm3 (+2.2%, p = 0.24). Dividing the study population into groups based on mannitol dose did not yield any statistically significant change. Conclusions: Human globe volume decreases after intravenous mannitol administration, while orbital volume increases. These volume changes occur during the time period when intraocular pressure normalizes, after the pressure-lowering effects of the drug. This novel volumetric information improves our understanding of mannitol’s mechanism of action and its effects on human ocular and periocular tissues.

Capacities for regulation of heart rate in fetal, infant, and adult rats

1965 ◽  
Vol 209 (6) ◽  
pp. 1095-1105 ◽  
Author(s):  
E. F. Adolph
Keyword(s):  
Heart Rate ◽  
Uterine Contraction ◽  
Adult Rats ◽  
Pregnant Rats ◽  
Infant Rats ◽  
Fine Wire ◽  
Before And After ◽  
Needle Prick ◽  
Age Range ◽  
Multiple Factor

In anesthetized pregnant rats, fine-wire electrodes were inserted into fetuses 14–21 days of age; electrocardiograms were recorded. What influences can control the heart rate at stages before and after nerves are functional in the heart? Percentage changes of heart rate are reported. Uterine contraction, needle prick, hypoxia, and hypercapnia transiently decelerated the heart at the earliest preneural stages. Norepinephrine injection into fetus accelerated the heart. In older fetuses, isopropylnorepinephrine and sometimes epinephrine also accelerated the heart. The heart rate therefore became susceptible to more influences. At birth, responses to needle prick and to hypoxia began to reverse, acceleration becoming the rule. Epinephrine and norepinephrine then induced transient decelerations; hyperoxia induced deceleration and an off-effect acceleration. In infant rats, all the responses were exaggerated compared with both those in fetuses and those in adults. Adult rats still responded to all the above agents, however. Especially in the age range from fetus to infant the capacities for regulation of heart rate augmented; a multiple-factor relation may be used to express the augmentation.

Ventilatory responses to hypoxia in rats pretreated with nonpeptide NK1 receptor antagonist CP-96,345

1994 ◽  
Vol 76 (4) ◽  
pp. 1528-1532 ◽  
Author(s):  
G. T. De Sanctis ◽  
F. H. Green ◽  
X. Jiang ◽  
M. King ◽  
J. E. Remmers
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Acute Hypoxia ◽  
Frequency Component ◽  
Nk1 Receptor ◽  
Adult Rats ◽  
Nk1 Receptors ◽  
Before And After ◽  
Sites Of Action

This study reports experiments designed to evaluate the role of neurokinin-1 (NK1) receptors for substance P (SP) in the ventilatory response to acute hypoxia. Ventilation was measured by indirect plethysmography in eight unanesthetized unrestrained adult rats before and after bolus injection of 1, 5, or 10 mg/kg (ip) of CP-96,345 (Pfizer), a potent nonpeptide competitive antagonist of the SP NK1 receptor. Ventilation was measured while the rats breathed air or 8% O2–92% N2 with and without administration of SP antagonist. Pretreatment with CP-96,345 decreased the magnitude of the hypoxic response in a dose-dependent fashion. Minute ventilation in rats pretreated with CP-96,345 was reduced by 22.1% (P < 0.05) at the highest dose (10 mg/kg), largely because of an attenuation of the frequency component. Although both control and treated rats responded to hypoxia with a decrease in duration of inspiration and expiration rats pretreated with CP-96,345 displayed a smaller decrease in inspiration and expiration than control rats (P < 0.05). We have recently shown that neuropeptide-containing fibers are important for mediating the tachypnic response during acute isocapnic hypoxia in rats. The attenuation in minute ventilation at the highest dose (10 mg/kg) is comparable in magnitude to the attenuation observed with neonatal capsaicin treatment, which permanently ablates neuropeptide-containing unmyelinated fibers. Accordingly, this previously reported role of capsaicin-sensitive nerves in the hypoxic ventilatory response of rats is probably attributable to released SP acting at NK1 receptors. One of the likely sites of action of SP antagonists is the carotid body.(ABSTRACT TRUNCATED AT 250 WORDS)

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