Relative latency of responses of chemoreceptor afferents from aortic and carotid bodies

1980 ◽  
Vol 48 (2) ◽  
pp. 362-369 ◽  
Author(s):  
S. Lahiri ◽  
T. Nishino ◽  
E. Mulligan ◽  
A. Mokashi

Discharges from aortic and carotid body chemoreceptor afferents were simultaneously recorded in 18 anesthetized cats to test the hypothesis that aortic chemoreceptors, because of their proximity to the heart, respond to changes in arterial blood gases before carotid chemoreceptors. We found that carotid chemoreceptor responses to the onset of hypoxia and hypercapnia, and to the intravenously administered excitatory drugs (cyanide, nicotine, and doxapram), preceded those of aortic chemoreceptors. Postulating that this unexpected result was due to differences in microcirculation and mass transport, we also investigated their relative speed of responses to changes in arterial blood pressure. The aortic chemoreceptors responded to decreases in arterial blood pressure before the carotid chemoreceptors, supporting the idea that the aortic body has microcirculatory impediments not generally present in the carotid body. These findings strengthened the concept that carotid bodies are more suited for monitoring blood gas changes due to respiration, whereas aortic bodies are for monitoring circulation.

2004 ◽  
Vol 96 (3) ◽  
pp. 865-870 ◽  
Author(s):  
Denise M. O'Driscoll ◽  
Guy E. Meadows ◽  
Douglas R. Corfield ◽  
Anita K. Simonds ◽  
Mary J. Morrell

The cardiovascular response to an arousal occurring at the termination of an obstructive apnea is almost double that to a spontaneous arousal. We investigated the hypothesis that central plus peripheral chemoreceptor stimulation, induced by hypercapnic hypoxia (HH), augments the cardiovascular response to arousal from sleep. Auditory-induced arousals during normoxia and HH (>10-s duration) were analyzed in 13 healthy men [age 24 ± 1 (SE) yr]. Subjects breathed on a respiratory circuit that held arterial blood gases constant, despite the increased ventilation associated with arousal. Arousals were associated with a significant increase in mean arterial blood pressure at 5 s ( P < 0.001) and with a significant decrease in the R-R interval at 3 s ( P < 0.001); however, the magnitude of the changes was not significantly different during normoxia compared with HH (mean arterial blood pressure: normoxia, 91 ± 4 to 106 ± 4 mmHg; HH, 91 ± 4 to 109 ± 5 mmHg; P = 0.32; R-R interval: normoxia, 1.12 ± 0.04 to 1.02 ± 0.05 s; HH, 1.09 ± 0.05 to 0.92 ± 0.04 s; P = 0.78). Mean ventilation increased significantly at the second breath postarousal for both conditions ( P < 0.001), but the increase was not significantly different between the two conditions (normoxia, 5.35 ± 0.40 to 9.57 ± 1.69 l/min; HH, 8.57 ± 0.63 to 11.98 ± 0.70 l/min; P = 0.71). We conclude that combined central and peripheral chemoreceptor stimulation with the use of HH does not interact with the autonomic outflow associated with arousal from sleep to augment the cardiovascular response.


1976 ◽  
Vol 230 (1) ◽  
pp. 19-24 ◽  
Author(s):  
G Mancia ◽  
JT Shepherd ◽  
DE Donald

Interactions among vascular reflexes evoked from carotid sinuses, carotid bodies, and cardiopulmonary region were examined in anesthetized, atropinized, and respired dogs with aortic nerves cut. The carotid sinuses were perfused at 220, 150, and 40-50 mmHg; the chemoreceptors were stimulated by perfusion with hypoxic hypercapnic blood. Cardiopulmonary vasomotor inhibition was interrupted by vagal cold block. Measurements were made of arterial blood pressure and of kidney and hindlimb vascular resistance. At sinus pressures less than 170-160 mmHg, cardiopulmonary vasomotor inhibition increased with increase in blood volume. At high sinus pressure, interruption of this augmented cardiopulmonary inhibition was as ineffective in changing vascular resistance as interruption of the lesser inhibition present during normovolemia. Chemoreceptor stimulation increased the response to vagal block at intermediate but not at high or low sinus pressure. The studies demonstrate the dominant role of the carotid sinus reflex when the three systems interact and the ineffectiveness of chemoreceptor stimulation when carotid or cardiopulmonary inhibition is maximal.


1994 ◽  
Vol 77 (1) ◽  
pp. 285-289 ◽  
Author(s):  
C. Suguihara ◽  
D. Hehre ◽  
E. Bancalari

To determine whether the neonatal hypoxic ventilatory depression is in part produced by an increased endogenous dopamine release that can depress the activity of central and peripheral chemoreceptors, 31 sedated and spontaneously breathing newborn piglets [age 5 +/- 1 (SD) days; weight 1.7 +/- 0.4 kg] were randomly assigned to an intact carotid body or a chemodenervated group. Minute ventilation (VE), arterial blood pressure, and cardiac output (CO) were measured in room air before infusion of saline or the dopamine antagonist flupentixol (0.2 mg/kg i.v.) and 15 min after drug infusion and were repeated after 10 min of hypoxia (inspiratory O2 fraction = 0.10). VE increased significantly after 10 min of hypoxia in the piglets that received flupentixol independent of whether the carotid bodies were intact or denervated. However, the increase in VE was largest and sustained throughout the 10 min of hypoxia only in the intact carotid body flupentixol group. As expected, the initial increase in VE with hypoxia was abolished by carotid body denervation. Changes in arterial blood gases, CO, and mean arterial blood pressure with hypoxia were not different among groups. These results demonstrate that flupentixol reverses the late hypoxic decrease in VE, acting through peripheral and central dopamine receptors. This effect is not related to changes in cardiovascular function or acid-base status.


Author(s):  
Yiannis Papachatzakis ◽  
Pantelis Theodoros Nikolaidis ◽  
Sofoklis Kontogiannis ◽  
Georgia Trakada

High-flow oxygen through nasal cannula (HFNC) provides adequate oxygenation and can be an alternative to noninvasive ventilation (NIV) for patients with hypoxemic respiratory failure. The aim of the present study was to assess the efficacy of HFNC versus NIV in hypercapnic respiratory failure. Patients (n = 40) who were admitted to the Emergency Department of Alexandra Hospital due to hypercapnic respiratory failure (PaCO2 ≥ 45 mmHg) were randomized assigned into two groups, i.e., an intervention group (use of HFNC, n = 20) and a control group (use of NIV, n = 20). During their hospitalization in the Intensive Care Unit, vital signs (respiratory and heart rate, arterial blood pressure) and arterial blood gases (ABG) were closely monitored on admission, after 24 h and at discharge. No difference between the two groups regarding the duration of hospitalization and the use of HFNC or NIV was observed (p > 0.05). On admission, the two groups did not differ in terms of gender, age, body mass index, APACHE score, predicted death rate, heart rate, arterial blood pressure and arterial blood gases (p > 0.05). Respiratory rate in the HFNC group was lower than in the NIV group (p = 0.023). At discharge, partial carbon dioxide arterial pressure (PaCO2) in the HFNC group was lower than in the NIV group (50.8 ± 9.4 mmHg versus 59.6 ± 13.9 mmHg, p = 0.024). The lowerPaCO2 in the HFNC group than in the NIV group indicated that HFNC was superior to NIV in the management of hypercapnic respiratory failure.


1982 ◽  
Vol 242 (1) ◽  
pp. R105-R108 ◽  
Author(s):  
R. S. Lillo ◽  
D. R. Jones

The precise role of carotid body chemoreceptors and systemic baroreceptors in cardiovascular responses during experimental diving in ducks is controversial. The diving responses of chronically baroreceptor-denervated, chemoreceptor-denervated, and combined baroreceptor- and chemoreceptor-denervated White Pekin ducks, Anas platyrhynchos, were compared with those of intact and sham-operated birds. All three types of denervation elevated predive heart rates on average by 100-150 beats/min. During submergence, the cardiac rate of the barodenervates quickly dropped and after 60 s stabilized at levels similar to those of submerged intact ducks for the remainder of a 2-min dive. However, arterial blood pressure declined drastically in the barodenervates. Ducks without functional carotid bodies showed significant bradycardia during submergence, although heart rate only fell to the predive rate of intact animals. Birds with combined baroreceptor and chemoreceptor denervation exhibited the same degree of bradycardia as chemoreceptor denervates, and arterial blood pressure rose spectacularly during a dive. It is concluded that during experimental diving in ducks 1) cardiac responses are not baroreflexive in origin, 2) the major portion of bradycardia is due to stimulation of carotid body chemoreceptors, and 3) intact system baroreceptors appear essential for maintenance of blood pressure.


2020 ◽  
Author(s):  
Bharti Bhandari ◽  
Manisha Mavai ◽  
Yogendra Raj Singh ◽  
Bharati Mehta ◽  
Omlata Bhagat

A single episode of breath-holding (BH) is known to elevate the blood pressure, and regular breathing exercise lowers the blood pressure. This prompted us to investigate how a series of BH epochs would affect the cardiovascular system. To observe arterial blood pressure (ABP) and heart rate (HR) changes associated with a series of “BH epochs” following maximum inspiration and maximum expiration and find the underlying mechanisms for the change by autonomic activity. Thirty-five healthy young adults were instructed to hold their breath repetitively, for 5 minutes, in two patterns, one following maximum inspiration and other following maximum expiration. ABP and ECG (for Heart Rate Variability) were continuously recorded at rest and during both the maneuvers. Capillary blood gases (BG) were zanalyzed at baseline and at the breakpoint of the last epoch of BH. ABP rose significantly at the breakpoint during both the maneuvers. No change in HR was observed. There was significant fall in PO2 from 94.7 (4.1) mmHg at baseline to 79.1 (9.0) mmHg during inspiratory and 76.90 (12.1) mmHg during expiratory BH. Similarly, SPO2 decreased from 96.3 (1.9) % at baseline to 95.4 (1.5) % and 94.5 (2.7) % during inspiratory and expiratory BH, respectively. Rise in PCO2 from 39.5(3.1) mmHg at baseline to 42.9 (2.7) mmHg and 42.1 (2.8) mmHg during inspiratory and expiratory BH respectively was observed. There was no significant correlation between blood gases and arterial blood pressure. Among HRV parameters, a significant decrease in SDNN, RMSSD, HFnu, total power and SD1/SD2 and the significant increase in LFnu, LF/HF and SD2 were observed during both BH patterns. Rhythmic BH patterns affect the cardiovascular system in similar way as a single episode of BH. Sympathetic overactivity could be the postulated mechanism for the same. © 2019 Tehran University of Medical Sciences. All rights reserved. Acta Med Iran 2019;57(8):492-498.


1986 ◽  
Vol 9 (6) ◽  
pp. 427-432 ◽  
Author(s):  
R. Fumagalli ◽  
T. Kolobow ◽  
P. Arosio ◽  
V. Chen ◽  
D.K. Buckhold ◽  
...  

A total of 44 preterm fetal lambs at great risk of developing respiratory failure were delivered by Cesarean section, and were then managed on conventional mechanical pulmonary ventilation. Fifteen animals initially fared well, and 14 of these were long term survivors. Twenty-nine other lambs showed a progressive deterioration in arterial blood gases within 30 minutes of delivery, of which 10 lambs were continued on mechanical pulmonary ventilation (20% survival), while the remaining 19 lambs were placed on an extracorporeal membrane lung respiratory assist (79% survival). Extracorporeal membrane lung bypass rapidly corrected arterial blood gas values, and permitted the use of high levels of CPAP instead of the continuation of mechanical pulmonary ventilation at high peak airway pressures. Improvement in lung function was gradual, and predictable. Early institution of extracorporeal respiratory assist using a membrane artificial lung rapidly corrected arterial blood gas values and significantly improved on neonate survival.


1999 ◽  
Vol 43 (4) ◽  
pp. 242
Author(s):  
MICHAEL ZAUGG ◽  
ELIANA LUCCHINETTI ◽  
MARCO P. ZALUNARDO ◽  
STEFAN ZUMSTEIN ◽  
DONAT R. SPAHN ◽  
...  

2006 ◽  
Vol 36 (5) ◽  
pp. 1444-1449
Author(s):  
Cláudio Corrêa Natalini ◽  
Renata Lehn Linardi ◽  
Alexandre da Silva Polydoro

The study was done to compare the heart rate, arterial blood pressure, arterial blood gases, respiratory rate, body temperature, and behavior after subarachnoid administration of hyperbaric morphine (MorphineD10), buprenorphine (BuprenorphineD10), methadone (Methadone D10), and 10% dextrose (D10) in conscious horses. Six adult horses were studied. Treatments were administered into the lombo-sacral subarachnoid space through an epidural catheter, MorphineD10 at 0.01mg kg-1, BuprenorphineD10 at 0.001mg kg-1, MethadoneD10 at 0.01mg kg-1, and 10% dextrose as a control group. The results showed that there are minimum changes in heart and respiratory rate, blood gases, blood pressure, and body temperature after subarachnoid administration of hyperbaric opioids in horses. No sedation and nor motor impairment or behavioral changes occur.


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