Mechanisms of Respiratory Responses to Vasodilator Drugs Urecholine (Carbaminoyl Beta-Methylcholine) and Nitroglycerine

1957 ◽  
Vol 189 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Robert T. Schopp ◽  
Thomas M. Gilfoil ◽  
William B. Youmans
Keyword(s):  
Blood Pressure ◽  
Sodium Cyanide ◽  
Respiratory Response ◽  
Vasodilator Drugs ◽  
Arterial Blood ◽  
Before And After ◽  
Bilateral Vagotomy ◽  
Alpha Chloralose ◽  
Respiratory Stimulation ◽  
Respiratory Responses

The effects on respiratory rate and amplitude following intravenous injection of the vasodilator drugs, Urecholine (carbaminoyl-beta-methylcholine) and nitroglycerine were determined in dogs before and after bilateral vagotomy and isolation of the carotid sinuses. The animals were anesthetized with sodium pentothal followed by alpha-chloralose (70 mg/kg). Following the procedures for denervation of sino-aortic pressoreceptors and carotid and aortic chemoreceptors the animals showed no respiratory response to 1–2 mg sodium cyanide. It was found that the respiratory stimulation which occurs during the fall in blood pressure induced by injection of Urecholine or nitroglycerine frequently persists after sino-aortic denervation. The respiratory stimulation in the denervated animals in response to nitroglycerine was reduced or prevented in individual experiments by counteracting the fall in arterial blood pressure by means of a pressure-regulating device. It is concluded that in the dosage used nitroglycerine, and possibly also Urecholine, exert their effects on respiration indirectly by causing alterations in blood pressure or blood flow rather than through any specific action on the respiratory center.

Mechanisms of Respiratory Stimulation During Hemorrhage

1957 ◽  
Vol 189 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Robert T. Schopp ◽  
Thomas M. Gilfoil ◽  
William B. Youmans
Keyword(s):  
Blood Flow ◽  
Rapid Onset ◽  
Sodium Cyanide ◽  
Sodium Pentobarbital ◽  
Before And After ◽  
Severe Hemorrhage ◽  
Bilateral Vagotomy ◽  
Flow Through ◽  
Respiratory Stimulation ◽  
Respiratory Responses

The immediate effects of severe hemorrhage on respiratory rate and amplitude were determined in dogs before and after bilateral vagotomy and isolation of the carotid sinuses. The animals were anesthetized with morphine (3 mg/kg) intramuscularly and sodium pentobarbital (15 mg/kg) intravenously. The sino-aortic denervated animals showed no respiratory responses to 1–2 mg of sodium cyanide. Most of the animals showed immediate respiratory stimulation in response to hemorrhage before denervation, and in a large percentage of these the stimulation still could be elicited by hemorrhage after sino-aortic denervation. The rapid onset of the stimulation in the denervated animals and the fact that slow withdrawal of blood to produce a certain level of hypotension caused less stimulation than rapid withdrawal would indicate that decreased blood flow through the respiratory center may not be the basis for the response.

Effects of Bilateral Vagotomy on Renal Function in the Rat

1971 ◽  
Vol 49 (5) ◽  
pp. 420-426 ◽  
Author(s):  
Paul F. Mercer
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Carotid Arteries ◽  
Control Group ◽  
Vagus Nerves ◽  
Renal Nerve ◽  
Arterial Blood ◽  
Before And After ◽  
Bilateral Vagotomy ◽  
Common Carotid Arteries

Renal function was studied in rats before and after section of the vagus nerves at the level of the common carotid arteries. In the control group of rats, sodium output and volume rate of urine flow increased following vagal section but glomerular filtration rate did not change. This response was not altered in other rats by desoxycorticosterone acetate, vasopressin, or renal nerve section. This response was similar to that seen in rats in which both common carotid arteries had been occluded. The natriuresis following bilateral vagotomy did not occur in rats in which the blood pressure was prevented from rising by means of aortic constriction. It is concluded that a natriuresis does occur following bilateral vagotomy. This natriuresis may be a result of the effect of arterial blood pressure following the vagotomy.

scholarly journals Modulation of respiratory motor output by cerebellar deep nuclei in the rat

2000 ◽  
Vol 89 (3) ◽  
pp. 996-1004 ◽  
Author(s):  
Fadi Xu ◽  
Donald T. Frazier
Keyword(s):  
Kainic Acid ◽  
Pressor Response ◽  
Cardiovascular Effects ◽  
Sodium Cyanide ◽  
Motor Output ◽  
Respiratory Response ◽  
Interposed Nucleus ◽  
Before And After ◽  
Lateral Nucleus ◽  
Respiratory Responses

The present study was undertaken to determine what roles the various cerebellar deep nuclei (CDN) play in modulation of respiration, especially during chemical challenges. Experiments were carried out in 12 anesthetized, tracheotomized, paralyzed, and ventilated rats. The integrated phrenic nerve activity (∫PN) was recorded as an index of respiratory motor output. A stimulating electrode was sequentially placed into the fastigial nucleus (FN), the interposed nucleus, and the lateral nucleus. Only stimulation of the FN significantly altered respiration, primarily via increasing respiratory frequency associated with a pressor response. The evoked respiratory responses persisted after blocking the pressor response via pretreatment with phenoxybenzamine or use of transient stimulation (<2 s) but were abolished by microinjection of kainic acid into the FN. To test the involvement of FN neurons in respiratory chemoreflexes, ventilation with hypercapnic gases mixture and intravenous injection of sodium cyanide were applied before and after CDN lesions induced by kainic acid. CDN lesions did not significantly alter eupneic breathing, but FN lesions attenuated the respiratory response to hypercapnia and sodium cyanide. We conclude that, with respect to the CDN in the rat, FN neurons uniquely modulate respiration independent of cardiovascular effects and facilitate respiratory responses mediated by activation of CO2 and O2 receptors.

Comparative study on effect of neutral spinal bath and neutral spinal spray on blood pressure, heart rate and heart rate variability in healthy volunteers

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Arundhati Goley ◽  
A. Mooventhan ◽  
NK. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
Group Analysis ◽  
Low Frequency ◽  
Single Session ◽  
Arterial Blood ◽  
Before And After ◽  
Instantaneous Heart Rate

Abstract Background Hydrotherapeutic applications to the head and spine have shown to improve cardiovascular and autonomic functions. There is lack of study reporting the effect of either neutral spinal bath (NSB) or neutral spinal spray (NSS). Hence, the present study was conducted to evaluate and compare the effects of both NSB and NSS in healthy volunteers. Methods Thirty healthy subjects were recruited and randomized into either neutral spinal bath group (NSBG) or neutral spinal spray group (NSSG). A single session of NSB, NSS was given for 15 min to the NSBG and NSSG, respectively. Assessments were taken before and after the interventions. Results Results of this study showed a significant reduction in low-frequency (LF) to high-frequency (HF) (LF/HF) ratio of heart rate variability (HRV) spectrum in NSBG compared with NSSG (p=0.026). Within-group analysis of both NSBG and NSSG showed a significant increase in the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (HR) (RRI) (p=0.002; p=0.009, respectively), along with a significant reduction in HR (p=0.002; p=0.004, respectively). But, a significant reduction in systolic blood pressure (SBP) (p=0.037) and pulse pressure (PP) (p=0.017) was observed in NSSG, while a significant reduction in diastolic blood pressure (DBP) (p=0.008), mean arterial blood pressure (MAP) (p=0.008) and LF/HF ratio (p=0.041) was observed in NSBG. Conclusion Results of the study suggest that 15 min of both NSB and NSS might be effective in reducing HR and improving HRV. However, NSS is particularly effective in reducing SBP and PP, while NSB is particularly effective in reducing DBP and MAP along with improving sympathovagal balance in healthy volunteers.

The Study of Dynamic Response to Acute Hemorrhage by Pulse Spectrum Analysis

2006 ◽  
Vol 34 (03) ◽  
pp. 449-460 ◽  
Author(s):  
Yu Hsin Chang ◽  
Chia I Tsai ◽  
Jaung Geng Lin ◽  
Yue Der Lin ◽  
Tsai Chung Li ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Steady State ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Spectrum Analysis ◽  
Pulse Spectrum ◽  
Acute Hemorrhage ◽  
Arterial Blood ◽  
Percentage Difference ◽  
Before And After

Traditional Chinese Medicine (TCM) holds that Blood and Qi are fundamental substances in the human body for sustaining normal vital activity. The theory of Qi, Blood and Zang-Fu contribute the most important theoretical basis of human physiology in TCM. An animal model using conscious rats was employed in this study to further comprehend how organisms survive during acute hemorrhage by maintaining the functionalities of Qi and Blood through dynamically regulating visceral physiological conditions. Pulse waves of arterial blood pressure before and after the hemorrhage were taken in parallel to pulse spectrum analysis. Percentage differences of mean arterial blood pressure and harmonics were recorded in subsequent 5-minute intervals following the hemorrhage. Data were analyzed using a one-way analysis of variance (ANOVA) with Duncan's test for pairwise comparisons. Results showed that, within 30 minutes following the onset of acute hemorrhage,the reduction of mean arterial blood pressure was improved from 62% to 20%. Throughout the process, changes to the pulse spectrum appeared to result in a new balance over time. The percentage differences of the second and third harmonics, which were related to kidney and spleen, both increased significantly than baseline and towards another steady state. Apart from the steady state resulting from the previous stage, the percentage difference of the 4th harmonic decreased significantly to another steady state. The observed change could be attributed to the induction of functional Qi, and is a result of Qi-Blood balancing activity that organisms hold to survive against acute bleeding.

Effects of β-Adrenoreceptor Antagonists on Sino-Aortic Baroreflex Sensitivity and Blood Pressure in Hypertensive Man

1979 ◽  
Vol 57 (3) ◽  
pp. 241-247 ◽  
Author(s):  
R. D. S. Watson ◽  
T. J. Stallard ◽  
W. A. Littler
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Older Patients ◽  
Acute Treatment ◽  
Baroreflex Sensitivity ◽  
Chronic Treatment ◽  
Positive Relationship ◽  
Initial Pulse ◽  
Arterial Blood ◽  
Before And After

1. Sensitivity of the sino-aortic baroreflex was investigated before and after acute (23 patients) and chronic (23 patients) β-adrenoreceptor antagonism in patients with essential hypertension. 2. Sensitivity was inversely related to age (r = −0·60) and systolic blood pressure (r = −0·46); a positive relationship was noted between sensitivity and initial pulse intervals (r = 0·40). 3. Sensitivity increased significantly in patients less than 40 years of age after chronic treatment. No change occurred after acute treatment or in older patients treated chronically. 4. The fall in ambulatory intra-arterial blood pressure after chronic treatment was unrelated to alteration of baroreflex sensitivity.

scholarly journals Severe hypoxaemia in field-anaesthetised white rhinoceros (Ceratotherium simum) and effects of using tracheal insufflation of oxygen

2004 ◽  
Vol 75 (2) ◽  
Author(s):  
M. Bush ◽  
J.P. Raath ◽  
D. Grobler ◽  
L. Klein
Keyword(s):  
Blood Pressure ◽  
Tracheal Intubation ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
White Rhinoceros ◽  
Severe Hypoxaemia ◽  
Before And After ◽  
Tracheal Insufflation ◽  
Free Ranging

White rhinoceros anaesthetised with etorphine and azaperone combination develop adverse physiological changes including hypoxia, hypercapnia, acidosis, tachycardia and hypertension. These changes are more marked in field-anaesthetised rhinoceros. This study was designed to develop a technique to improve safety for field-anaesthetised white rhinoceros by tracheal intubation and oxygen insufflation. Twenty-five free-ranging white rhinoceros were anaesthetised with an etorphine and azaperone combination for translocation or placing microchips in their horns. Once anaesthetised the rhinoceros were monitored prior to crating for transportation or during microchip placement. Physiological measurements included heart and respiratory rate, blood pressure and arterial blood gas samples. Eighteen rhinoceros were intubated using an equine nasogastric tube passed nasally into the trachea and monitored before and after tracheal insufflation with oxygen. Seven rhinoceros were not intubated or insufflated with oxygen and served as controls. All anaesthetised rhinoceros were initially hypoxaemic (percentage arterial haemoglobin oxygen saturation (% O2Sa) = 49 % + 16 (mean + SD) and PaO2 = 4.666 + 1.200 kPa (35 + 9 mm Hg)), hypercapnic (PaCO2 = 8.265 + 1.600 kPa (62 + 12 mm Hg)) and acidaemic (pHa = 7.171 + 0.073 ). Base excess was -6.7 + 3.9 mmol/ℓ, indicating a mild to moderate metabolic acidosis. The rhinoceros were also hypertensive (systolic blood pressure = 21.861 + 5.465 kPa (164 + 41 mm Hg)) and tachycardic (HR = 107 + 31/min). Following nasal tracheal intubation and insufflation, the % O2Sa and PaO2 increased while blood pHa and PaCO2 remained unchanged.Tracheal intubation via the nose is not difficult, and when oxygen is insufflated, the PaO2 and the % O2Sa increases, markedly improving the safety of anaesthesia, but this technique does not correct the hypercapnoea or acidosis. After regaining their feet following reversal of the anaesthesia, the animals' blood gas values return towards normality.

scholarly journals Interrelationships between pulse arrival time and arterial blood pressure during postural transitions before and after spaceflight

2019 ◽  
Vol 127 (4) ◽  
pp. 1050-1057
Author(s):  
Katelyn N. Wood ◽  
Danielle K. Greaves ◽  
Richard L. Hughson
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Arrival Time ◽  
Standing Posture ◽  
Pulse Arrival Time ◽  
Arterial Blood ◽  
Increased Risk ◽  
Before And After ◽  
Acute Changes ◽  
Pulse Arrival

We tested the hypothesis that acute changes in arterial blood pressure (BP) when astronauts moved between supine and standing posture before and after spaceflight can be tracked by beat-to-beat changes in pulse arrival time (PAT). Nine male crewmembers (45 ± 7 yr of age; mean mission length: 165 ± 13 days) participated in a standardized supine-to-sit-to-stand test (5 min-30 s-3 min) before flight and 1 day following return to Earth with continuous monitoring of ECG and finger arterial BP. PAT was determined from the R-wave of the ECG to the foot of the BP waveform. On average, modest cardiovascular deconditioning was detected by ~10 beats/min increase in heart rate in supine and standing posture after spaceflight ( P < 0.05). When looking across the full data collection period, the r2 values between inverse of PAT (1/PAT) and systolic (SBP) and diastolic BP (DBP) varied considerably between individuals (SBP preflight 0.142 ± 0.186, postflight 0.262 ± 0.243). Individual variability was consistent during periods of transition (SBP preflight 0.284 ± 0.324, postflight 0.297 ± 0.269); however, when SBP dropped >20 mmHg, r2 was significant in 5 of 5 preflight tests and 5 of 7 postflight tests. The standard error of the estimate based on a simple linear model during both pre- and postflight testing was 9–11 mmHg for SBP and 6–7 mmHg for DBP. Overall, the results support the hypothesis that PAT tracked dynamic changes in BP. PAT as a noninvasive, nonintrusive surrogate for changes in BP could be developed as an indicator of risk for syncope on return from spaceflight or other Earth-based applications. NEW & NOTEWORTHY Astronauts returning to Earth’s gravity are at increased risk of low blood pressure on standing. Arterial pulse arrival time tracked the decrease in arterial blood pressure on moving from supine to upright posture. Nonintrusive technology providing indicators sensitive to acute changes in blood pressure could act as an early warning system to identify risk for hypotension that place astronauts, or people on Earth, at risk of impaired cognitive performance, fainting, and falls.

Cardiopulmonary reflexes and blood pressure in exercising sinoaortic-denervated dogs

1984 ◽  
Vol 57 (5) ◽  
pp. 1417-1421 ◽  
Author(s):  
D. A. Daskalopoulos ◽  
J. T. Shepherd ◽  
S. C. Walgenbach
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Vagal Afferents ◽  
Systemic Resistance ◽  
Vigorous Exercise ◽  
Arterial Blood ◽  
Resistance Vessels ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Cardiopulmonary Receptors

To examine the role of cardiopulmonary receptors in arterial blood pressure regulation during and after exercise, conscious dogs with chronic sinoaortic denervation were subjected to 12 min of light exercise and 12 min of exercise that increased in severity every 3 min. Hemodynamic measurements were made before and after interruption of cardiopulmonary afferents by bilateral cervical vagotomy. During both exercise protocols, after an initial transient decrease, the arterial blood pressure remained close to resting values before and after vagotomy. On cessation of the graded exercise, the arterial blood pressure did not change before, but a rapid and sustained increase in pressure occurred after vagotomy. At the time of this increase the cardiac output and heart rate were returning rapidly to the resting level. The study demonstrates that in the chronic absence of arterial baroreflexes, vagal afferents prevent a rise in arterial blood pressure after vigorous exercise presumably by the action of cardiopulmonary receptors causing a rapid dilatation of systemic resistance vessels.

A role for NMDA receptors in posthypoxic frequency decline in the rat

1998 ◽  
Vol 274 (6) ◽  
pp. R1546-R1555 ◽  
Author(s):  
Sharon K. Coles ◽  
Paul Ernsberger ◽  
Thomas E. Dick
Keyword(s):  
Nmda Receptors ◽  
Receptor Activation ◽  
Respiratory Pattern ◽  
Breathing Frequency ◽  
Respiratory Response ◽  
Arterial Blood ◽  
Before And After ◽  
High Doses ◽  
The Brain ◽  
Nmda Receptor Activation

Posthypoxic frequency decline (PHFD) refers to the undershoot in respiratory frequency that follows brief hypoxic exposures. Lateral pontine neurons are required for PHFD. The neurotransmitters involved in the circuit that activate and/or are released by these pontine neurons regulating PHFD are unknown. We hypothesized that N-methyl-d-aspartate (NMDA) receptors are required for PHFD, because of the similarity in respiratory pattern after blocking lateral pontine activity or NMDA receptors. Furthermore, we hypothesized that the location of these NMDA receptors could be visualized by optimizing binding affinity with spermidine. In vagotomized, anesthetized rats ( n = 16), cardiorespiratory responses to hypoxia (8% O2, 30–90 s) were recorded before and after dizocilpine (10 μg-1 mg/kg iv), and NMDA receptors were mapped with [3H]dizocilpine ( n = 6). Dizocilpine elicited a dose-related effect on PHFD, blocking PHFD at high doses. Resting arterial blood pressure and breathing frequency decreased with high doses of dizocilpine, but the respiratory response to hypoxia remained intact. Our novel anatomical data indicate that NMDA receptors were widespread but distributed differentially in the brain stem. We conclude that NMDA receptors are located in pontine and medullary respiratory-related regions and that PHFD requires NMDA-receptor activation.

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