Rapid and transient excitation of respiration mediated by central chemoreceptor

1988 ◽  
Vol 64 (4) ◽  
pp. 1369-1375 ◽  
Author(s):  
H. Arita ◽  
N. Kogo ◽  
K. Ichikawa
Keyword(s):  
Control System ◽  
Dynamic Properties ◽  
Respiratory Rhythm ◽  
Respiratory Control ◽  
Facilitatory Effect ◽  
Onset Latency ◽  
Central Chemoreceptors ◽  
Spontaneously Breathing ◽  
Respiratory Phases ◽  
Stimulation Of

We evaluated rapid and transient changes in phrenic nerve (PN) and internal intercostal (IIC) activities when 0.2-0.5 ml of saline saturated with 100% CO2 was injected into the vertebral artery during various respiratory phases in decerebrated spontaneously breathing cats. The injections evoked an initial transient inhibition of ongoing PN or IIC activity with a mean onset latency of 0.17 s, followed by excitation of subsequent respiratory activities with an onset latency ranging from 0.4 to 2.7 s; the average onset latency of expiratory excitation (1.49 s) was significantly longer than that of inspiratory facilitation (0.89 s). The initial inhibitory responses were analogous to reflex effects of injections of phenyl biguanide, indicating that the initial inhibition was due to activation of vascular nociceptors and the subsequent excitation was due to stimulation of the central chemoreceptors. In addition, CO2-saline injections during hypocapnic apnea developed a quick reappearance of respiratory rhythm, and the first facilitatory effect appeared in tonic IIC activity, which became more active before rhythm started. In summary, the present study, by use of a technique of vertebral arterial injections of 100% CO2-saline, revealed dynamic properties of respiratory control system mediated by central chemoreceptors and vascular nociceptors.

In vivo study on medullary H(+)-sensitive neurons

1990 ◽  
Vol 69 (4) ◽  
pp. 1408-1412 ◽  
Author(s):  
N. Kogo ◽  
H. Arita
Keyword(s):  
Time Course ◽  
Direct Application ◽  
Ventrolateral Medulla ◽  
Similar Time ◽  
Central Chemoreceptors ◽  
Ph Dependent ◽  
Spontaneously Breathing ◽  
Medullary Neurons ◽  
Stimulation Of

Using the micro pressure ejection technique, we examined responses of medullary neurons with nonphasic discharges (164 units) to direct application of acidified mock cerebrospinal fluid (CSF, pH 6.85-7.05) in decerebrated spontaneously breathing cats. We found 16 H(+)-sensitive cells; they were excited promptly on application of approximately 500 pl of acidified mock CSF in the vicinity of the neuron under investigation, whereas they were unaffected by microejection of the control mock CSF (pH 7.25-7.60). Of the 16 H(+)-sensitive cells, 10 units were further found to be excited by transcapillary stimulation of the central chemoreceptors by using a method of intravertebral arterial injection of CO2-saturated saline. The discharges increased in a similar time course to that of ventilatory augmentation. Distributions of these 10 specific H(+)-sensitive cells were found in the vicinity of nucleus tractus solitarii as well as deep in the ventrolateral medulla. The present results suggest a possibility that pH-dependent central chemoreceptors, if any, would be located in two distinct medullary regions described in this study.

Coupling between respiratory and stepping rhythms during locomotion in decerebrate cats

1989 ◽  
Vol 67 (1) ◽  
pp. 110-115 ◽  
Author(s):  
K. Kawahara ◽  
S. Kumagai ◽  
Y. Nakazono ◽  
Y. Miyamoto
Keyword(s):  
Gastrocnemius Muscle ◽  
Respiratory Rhythm ◽  
Mesencephalic Locomotor Region ◽  
Left Hemidiaphragm ◽  
The Mean ◽  
Locomotor Patterns ◽  
Gastrocnemius Muscles ◽  
Spontaneously Breathing ◽  
Decerebrate Cats ◽  
Stimulation Of

To determine whether and how the strength of coupling between respiratory and stepping rhythms varies depending on locomotor patterns, correlation analysis was done of diaphragmatic and gastrocnemius muscle activities. In spontaneously breathing cats decerebrated at the precollicular-post-mammillary level, tonic electrical stimulation was delivered to the mesencephalic locomotor region to induce locomotion on a treadmill. Electromyograms were recorded from the left hemidiaphragm and the bilateral gastrocnemius muscles. Various locomotor patterns were elicited by changes in the belt speed of the treadmill and in the intensity of stimulation of the mesencephalic locomotor region. Cross-correlograms between diaphragmatic and gastrocnemius activities showed that coupling was absent or weak when the cats walked slowly. The strength of locomotor-respiratory coupling tended to increase as the mean stepping interval shortened. When the animals were galloping, the respiratory rhythm was entrained 1:1 with the stepping rhythm. This study showed that the strength of coupling between respiratory and stepping rhythms varied depending on the locomotor patterns elicited, especially on whether the animals were running.

CO2 microdialysis in retrotrapezoid nucleus of the rat increases breathing in wakefulness but not in sleep

1999 ◽  
Vol 87 (3) ◽  
pp. 910-919 ◽  
Author(s):  
Aihua Li ◽  
Margaret Randall ◽  
Eugene E. Nattie
Keyword(s):  
Control System ◽  
Respiratory Control ◽  
Semipermeable Membrane ◽  
Ph Change ◽  
Microdialysis Probe ◽  
Retrotrapezoid Nucleus ◽  
Central Chemoreceptors ◽  
End Tidal ◽  
The Brain ◽  
Behavioral Criteria

Central chemoreceptors are widespread within the brain stem. We suggest that their function at some sites may vary with the state of arousal. In this study, we tested the hypothesis that the function of chemoreceptors in the retrotrapezoid nucleus (RTN) varies with sleep and wakefulness. In unanesthetized rats, we produced focal acidification of the RTN by means of a microdialysis probe (tip containing the semipermeable membrane = 1-mm length, 240-μm diameter, and 45-nl volume). With the use of a dialysate equilibrated with 25% CO2, the tissue pH change (measured in anesthetized animals) was 1) limited to within 550 μm of the probe and, 2) at the probe tip, was equivalent to that observed with end-tidal[Formula: see text] of 63 Torr. This focal acidification of the RTN increased ventilation significantly by 24% above baseline, on average, in 13 trials in seven rats only during wakefulness. The effect was entirely due to an increase in tidal volume. During sleep defined by behavioral criteria, ventilation was unaffected, on average, in 10 trials in seven rats. During sleep, the chemoreceptors in the RTN appear to be inactive, or, if active, the respiratory control system either is not responding or is responding with very low gain. Because ventilation is increased during sleep with all central chemoreceptor sites stimulated via systemic CO2 application, other central chemoreceptor locations must have enhanced effectiveness.

scholarly journals Periodic Breathing in Heart Failure Explained by Dynamic and Static Properties of Respiratory Control

2015 ◽  
Vol 9s1 ◽  
pp. CMC.S18761 ◽  
Author(s):  
Tadayoshi Miyamoto ◽  
Hidehiro Nakahara ◽  
Shinya Ueda ◽  
Kou Manabe ◽  
Eriko Kawai ◽  
...  
Keyword(s):  
Heart Failure ◽  
Control System ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
Lag Time ◽  
Open Loop ◽  
Regulation Of Respiration ◽  
Respiratory Chemoreflex

Objective The respiratory operating point is determined by the interplay between the controller and plant subsystem elements within the respiratory chemoreflex feedback system. This study aimed to establish the methodological basis for quantitative analysis of the open-loop dynamic properties of the human respiratory control system and to apply the results to explore detailed mechanisms of the regulation of respiration and the possible mechanism of periodic breathing in chronic heart failure. Methods and Results In healthy volunteers, we measured arterial CO2 partial pressure (PaCO2) and minute ventilation (V̇E) to estimate the dynamic properties of the controller (PaCO2→V̇E relation) and plant (V̇E→PaCO2 relation). The dynamic properties of the controller and plant approximated first- and second-order exponential models, respectively, and were described using parameters including gain, time constant, and lag time. We then used the open-loop transfer functions to simulate the closed-loop respiratory response to an exogenous disturbance, while manipulating the parameter values to deviate from normal values but within physiological ranges. By increasing both the product of gains of the two subsystem elements (total loop gain) and the lag time, the condition of system oscillation (onset of periodic breathing) was satisfied. Conclusion When abnormality occurs in a part of the respiratory chemoreflex system, instability of the control system is amplified and may result in the manifestation of respiratory abnormalities such as periodic breathing.

Neural Patterns Associated with Ventilatory Movements in Dragonfly Larvae

1970 ◽  
Vol 52 (1) ◽  
pp. 167-175
Author(s):  
P. J. MILL
Keyword(s):  
Control System ◽  
Motor Activity ◽  
Action Potentials ◽  
Motor Units ◽  
The Other ◽  
Ventilatory Control ◽  
Expiratory Phase ◽  
Segmental Nerve ◽  
Ventral Muscle ◽  
Stimulation Of

1. Rhythmic bursts of motor activity associated with the expiratory phase of ventilation have been recorded from the second lateral segmental nerves of posterior abdominal ganglia in Aeshna and Anax larvae. 2. In Aeshna the rhythmic expiratory bursts contain one, or sometimes two, motor units; whereas in Anax there are almost invariably three units. In both animals only one unit is associated with action potentials in the respiratory dorso-ventral muscle. 3. Motor activity synchronized with the expiratory bursts in the second nerves has been recorded from the other lateral nerves and from the last unpaired nerve. In addition the fifth lateral nerves carry inspiratory bursts. 4. It has been confirmed that stimulation of a first segmental nerve can re-set the ventilatory rhythm by initiating an expiratory burst in the second nerves. The original frequency is immediately resumed on cessation of stimulation. 5. The nature of the ventilatory control system in dragonfly larvae is discussed in relation to other rhythmic systems in the arthropods.

Fastigial nucleus-mediated respiratory responses depend on the medullary gigantocellular nucleus

2001 ◽  
Vol 91 (4) ◽  
pp. 1713-1722 ◽  
Author(s):  
Fadi Xu ◽  
Tongrong Zhou ◽  
Tonya Gibson ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Ibotenic Acid ◽  
Major Effect ◽  
Fastigial Nucleus ◽  
Respiratory Response ◽  
The Right ◽  
Spontaneously Breathing ◽  
Respiratory Responses ◽  
Gigantocellular Nucleus ◽  
Stimulation Of

Electrical stimulation of the rostral fastigial nucleus (FNr) alters respiration via activation of local neurons. We hypothesized that this FNr-mediated respiratory response was dependent on the integrity of the nucleus gigantocellularis of the medulla (NGC). Electrical stimulation of the FNr in 15 anesthetized and tracheotomized spontaneously breathing rats significantly altered ventilation by 35.2 ± 11.0% ( P < 0.01) with the major effect being excitatory (78%). This respiratory response did not significantly differ from control after lesions of the NGC via bilateral microinjection of kainic or ibotenic acid (4.5 ± 1.9%; P > 0.05) but persisted in sham controls. Eight other rats, in which horseradish peroxidase (HRP) solution was previously microinjected into the left NGC, served as nonstimulation controls or were exposed to either 15-min repeated electrical stimulation of the right FNr or hypercapnia for 90 min. Histochemical and immunocytochemical data showed that the right FNr contained clustered HRP-labeled neurons, most of which were double labeled with c-Fos immunoreactivity in both electrically and CO2-stimulated rats. We conclude that the NGC receives monosynaptic FNr inputs and is required for fully expressing FNr-mediated respiratory responses.

Adaptation in the respiratory control system

2003 ◽  
Vol 81 (8) ◽  
pp. 765-773 ◽  
Author(s):  
James Duffin ◽  
Safraaz Mahamed
Keyword(s):  
Experimental Data ◽  
Control System ◽  
Steady State ◽  
Graphical Model ◽  
Respiratory Control ◽  
Ventilatory Responses ◽  
System A ◽  
Hypoxia Adaptation ◽  
Peripheral Chemoreflex

Exposure to hypoxia, whether for short or prolonged periods or for repeated episodes, produces alterations in the ventilatory responses. This review presents evidence that these adaptations are likely to be mediated by adaptations in the respiratory chemoreflexes, particularly the peripheral chemoreflex, and proposes models of respiratory control explaining the observed changes in ventilation. After a brief introduction to the respiratory control system, a graphical model is developed that illustrates the operation of the system in the steady state, which will be used later. Next, the adaptations in ventilatory responses to hypoxia that have been observed are described, and methods of measuring the alterations in the chemoreflexes that might account for them are discussed. Finally, experimental data supporting the view that changes in the activity of the peripheral chemoreflex can account for the ventilatory adaptations to hypoxia are presented and incorporated into models of chemoreflex behaviour during exposures to hypoxia of various durations.Key words: respiration, chemoreflexes, hypoxia, adaptation, models.

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