Do Carotid Chemoreceptors Inhibit the Hyperventilatory Response to Heavy Exercise?

1994 ◽  
Vol 19 (3) ◽  
pp. 350-359 ◽  
Author(s):  
Jerome A. Dempsey ◽  
Curtis A. Smith
Keyword(s):  
Tidal Volume ◽  
Key Words ◽  
Carotid Body ◽  
Motor Output ◽  
Heavy Exercise ◽  
Feed Forward ◽  
Carotid Chemoreceptors ◽  
Carotid Body Denervation

In this paper two types of evidence are presented which question the commonly presumed role of carotid chemoreceptor stimulation as the primary mediator of the hyperventilatory response to heavy exercise. First, carotid-body denervation in ponies increases their hyperventilatory response to heavy exercise. Second, the awake dog and the goat at rest show an immediate and substantial depression of tidal volume and of ventilation when their isolated carotid chemoreceptors are made hypocapnic. Accordingly, it is proposed that during heavy exercise the carotid chemoreceptors are inhibitory to respiratory motor output and that the cause of the hyperventilatory response originates from extrachemoreceptor, locomotor-linked, feed-forward stimuli. Key words: hypocapnic inhibition, medullary chemoreceptors, locomotor-linked stimuli, feed-forward

Hypoxic arousal in intact and carotid chemodenervated sleeping cats

1981 ◽  
Vol 51 (5) ◽  
pp. 1294-1299 ◽  
Author(s):  
J. A. Neubauer ◽  
T. V. Santiago ◽  
N. H. Edelman
Keyword(s):  
Eye Movement ◽  
Slow Wave ◽  
Carotid Body ◽  
Rem Sleep ◽  
Severe Hypoxia ◽  
Rapid Eye Movement ◽  
Carotid Chemoreceptors ◽  
Carotid Bodies ◽  
Arterial O2 Saturation ◽  
Carotid Body Denervation

To determine whether the carotid chemoreceptors or hyperpnea are required for arousal from sleep by hypoxia, 14 sleep-deprived cats were studied during slow-wave (SWS) and rapid-eye-movement (REM) sleep. Rapid hypoxia was produced by inhalation of 5% O2 in N2 or 6% CO in 40% O2 by intact cats and 5% O2 in N2 after carotid body denervation. Preliminary studies identified a period of SWS unassociated with spontaneous arousals. In 69 studies during SWS unassociated with spontaneous arousals, arterial O2 saturation (SaO2) values at arousal were: 47.1 +/- 1.5% (mean +/- SE) (5% O2, intact); 48.9 +/- 1.4% (6% CO, intact); and 49.9 +/- 2.0% (5% O2, denervated). During SWS associated with spontaneous arousals, SaO2 values at arousal were 71.6 +/- 1.8% (5% O2, intact). Arousal from REM occurred at significantly lower values: 31.7 +/- 3.9% (6% CO, intact) and 43.5 +/- 2.3% (5% O2, intact). During both SWS and REM, inhalation of 5% O2 by intact animals caused a substantial increase in ventilation while 6% CO did not. We conclude that more severe hypoxia is required for arousal from SWS when studies are done in a period unassociated with spontaneous arousals than from SWS associated with spontaneous arousals. Hypoxic arousal does not appear to require activation of the carotid bodies or hyperpnea.

Role of the carotid bodies in chemosensory ventilatory responses in the anesthetized mouse

2004 ◽  
Vol 97 (4) ◽  
pp. 1401-1407 ◽  
Author(s):  
Masahiko Izumizaki ◽  
Mieczyslaw Pokorski ◽  
Ikuo Homma
Keyword(s):  
Tidal Volume ◽  
Carotid Body ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Whole Body ◽  
Sudden Increase ◽  
Ventilatory Responses ◽  
Carotid Bodies ◽  
Before And After ◽  
Carotid Body Denervation

We examined the effects of carotid body denervation on ventilatory responses to normoxia (21% O2 in N2 for 240 s), hypoxic hypoxia (10 and 15% O2 in N2 for 90 and 120 s, respectively), and hyperoxic hypercapnia (5% CO2 in O2 for 240 s) in the spontaneously breathing urethane-anesthetized mouse. Respiratory measurements were made with a whole body, single-chamber plethysmograph before and after cutting both carotid sinus nerves. Baseline measurements in air showed that carotid body denervation was accompanied by lower minute ventilation with a reduction in respiratory frequency. On the basis of measurements with an open-circuit system, no significant differences in O2 consumption or CO2 production before and after chemodenervation were found. During both levels of hypoxia, animals with intact sinus nerves had increased respiratory frequency, tidal volume, and minute ventilation; however, after chemodenervation, animals experienced a drop in respiratory frequency and ventilatory depression. Tidal volume responses during 15% hypoxia were similar before and after carotid body denervation; during 10% hypoxia in chemodenervated animals, there was a sudden increase in tidal volume with an increase in the rate of inspiration, suggesting that gasping occurred. During hyperoxic hypercapnia, ventilatory responses were lower with a smaller tidal volume after chemodenervation than before. We conclude that the carotid bodies are essential for maintaining ventilation during eupnea, hypoxia, and hypercapnia in the anesthetized mouse.

Effects of carotid body denervation on respiratory pattern of awake cats

1979 ◽  
Vol 46 (6) ◽  
pp. 1127-1131 ◽  
Author(s):  
H. Gautier ◽  
M. Bonora
Keyword(s):  
Tidal Volume ◽  
Carotid Body ◽  
Inspiratory Flow ◽  
Respiratory Pattern ◽  
Oxygen Breathing ◽  
Before And After ◽  
Inspiratory Activity ◽  
The Mean ◽  
Awake Cats ◽  
Carotid Body Denervation

Eight awake cats have been studied before and after carotid denervation during air and oxygen breathing, and during hypercapnia. Analysis of the variables that characterize the spirogram shows that carotid denervation consistently results in a decrease of the mean inspiratory flow (VT/TI), causing a decrease in tidal volume (VT) and ventilation with a relative alveolar hypercapnia. In carotid-denervated animals, inhalation of oxygen results in an increase in ventilation due to an augmentation of VT/TI and VT and a relative hypocapnia. TI does not significantly change in the different conditions whereas TE is significantly affected. TE seems therefore to be more closely related to the rate of rise of inspiratory activity than to inspiratory duration.

Respiratory adaptations to dead space loading during maximal incremental exercise

1991 ◽  
Vol 70 (1) ◽  
pp. 55-62 ◽  
Author(s):  
C. McParland ◽  
J. Mink ◽  
C. G. Gallagher
Keyword(s):  
Tidal Volume ◽  
Carotid Body ◽  
Dead Space ◽  
Breathing Pattern ◽  
Normal Subjects ◽  
Time Profile ◽  
Incremental Exercise ◽  
Respiratory Frequency ◽  
Heavy Exercise ◽  
Ventilatory Capacity

We examined the effects of dead space (VD) loading on breathing pattern during maximal incremental exercise in eight normal subjects. Addition of external VD was associated with a significant increase in tidal volume (VT) and decrease in respiratory frequency (f) at moderate and high levels of ventilation (VI); at a VI of 120 l/min, VT and f with added VD were 3.31 +/- 0.33 liters and 36.7 +/- 6.7 breaths/min, respectively, compared with 2.90 +/- 0.29 liters and 41.8 +/- 7.3 breaths/min without added VD. Because breathing pattern does not change with CO2 inhalation during heavy exercise (Gallagher et al. J. Appl. Physiol. 63: 238–244, 1987), the breathing pattern response to added VD is probably a consequence of alteration in the PCO2 time profile, possibly sensed by the carotid body and/or airway-pulmonary chemoreceptors. The increase in VT during heavy exercise with VD loading indicates that the tachypneic breathing pattern of heavy exercise is not due to mechanical limitation of maximum ventilatory capacity at high levels of VT.

Dynamic ventilatory responses to CO2 in the awake lamb: role of the carotid chemoreceptors

1991 ◽  
Vol 71 (6) ◽  
pp. 2198-2205 ◽  
Author(s):  
J. L. Carroll ◽  
E. Canet ◽  
M. A. Bureau
Keyword(s):  
Time Delay ◽  
Carotid Body ◽  
Time Course ◽  
Step Change ◽  
Co2 Response ◽  
Carotid Chemoreceptors ◽  
Ventilatory Responses ◽  
Central Chemoreceptors ◽  
Volume Response

In awake lambs we investigated the role of the peripheral chemoreceptors in producing dynamic ventilatory (VE) responses to CO2. The immediate VE response, within 15 s, to transient CO2 inhalation was studied in two groups: 1) five lambs before carotid denervation and 2) the same lambs after carotid denervation. The time course of VE responses during the first 60 s after a step change to 8% inspired CO2 was also studied in lambs after carotid denervation and in a group of six carotid body-intact lambs 10–11 days of age. Acute CO2 responses were assessed using step changes to various concentrations of CO2 + air and CO2 + O2, while VE was recorded breath by breath. Intact lambs exhibited a brisk VE response to step changes in CO2, beginning after 3–5 s. Hyperoxia altered but did not suppress the dynamic VE CO2 response when the carotid chemoreceptors were intact. Carotid denervation markedly reduced the VE response during the first 25 s after a CO2 step change, revealing the time delay required for the central chemoreceptors to produce an effective VE response. The residual VE response remaining after CD was thought to be mediated by the remaining aortic body chemoreceptors and was eliminated by adding O2 to the CO2 challenges. However, after carotid denervation, even with CO2 + hyperoxia, the onset of a small tidal volume response was apparent by 10–12 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid chemoreceptors influence arterial pressure in intact and aortic-denervated rats

1992 ◽  
Vol 262 (4) ◽  
pp. R677-R683 ◽  
Author(s):  
K. G. Franchini ◽  
E. M. Krieger
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Carotid Body ◽  
Hypotensive Effect ◽  
Carotid Chemoreceptors ◽  
Arterial Pressure Variability ◽  
Before And After ◽  
The Mean

The objective of the present study was to analyze the role of the arterial chemoreceptors in arterial pressure alterations produced by sinoaortic denervation (SAD) in rats. The mean arterial pressure during 2 h of continuous computerized beat-to-beat recordings was higher after aortic denervation (AD; 130 +/- 2 and 124 +/- 3 mmHg, respectively), lower after sinus denervation (SD; 101 +/- 1 and 101 +/- 3 mmHg), and remained unaltered after SAD (121 +/- 3 and 108 +/- 2 mmHg) 1 and 20 days after denervation compared with control rats (114 +/- 1 mmHg). Hypotensive effect of SD was confirmed when arterial pressure was recorded in the same animal before and after SD (from 112 +/- 2 to 103 +/- 2 mmHg). A similar effect was observed after isolated carotid body artery (CBA) ligation (from 114 +/- 3 to 104 +/- 3 mmHg). Furthermore, CBA ligation attenuated by 13% the hypertension after AD (from 136 +/- 2 to 118 +/- 3 mmHg). Bradycardic response to phenylephrine and arterial pressure variability were markedly altered by SAD and AD but remained normal after SD. In contrast, the chemoreflex (intravenous KCN) was abolished after SAD, SD, and CBA ligation but was preserved after AD. These data suggest that the arterial pressure alteration produced by SAD in rats represents the net effect of the abolition of inhibitory (baroreceptor deafferentation) and excitatory (chemoreceptor deafferentation) influences on the arterial pressure.

THE ROLE OF COMMUNICATIVE AND FUNCTIONAL APPROACH IN THE TRANSLATION OF SCIENTIFIC AND TECHNICAL LITERATURE (Ukrainian — German discourse)

2019 ◽  
Vol 26 (27) ◽  
pp. 68-74
Author(s):  
Svitlana Gruschko
Keyword(s):  
Key Words ◽  
Information Exchange ◽  
Functional Approach ◽  
Communication Structure ◽  
Technical Literature ◽  
Translation Strategy ◽  
Purposeful Activity

The article investigates the role of communicative-functional approach in the translation of scientific and technical literature, when the translation itself is seen as a tool to accomplish purposeful activity of communicators, representatives of different interlingual groups. In practical terms, the difficulties of translating scientific and technical texts are due to the peculiarities of scientific style, insufficient understanding of the terminology of a particular field of knowledge, which complicates the choice of adequate translation solutions. In this context, an important role is played by the translation strategy, where the communicativefunctional approach dominates. The translation is implicitly included in the communication structure between the author and the recipient. The relevance of the article is determined by the necessity of studying the problems of scientific and technical literature translation, taking into account the current realities of interlanguage information exchange. Key words: communicative-functional approach, interlingual communication, translation, structure

INTERPRETATIONAL FIELD OF THE CONCEPT “WOMAN” IN ENGLISH AND KYRGYZ LINGUOCULTURES

2019 ◽  
pp. 54-56
Author(s):  
Баяманова М.С.
Keyword(s):  
Comparative Study ◽  
Key Words ◽  
Analytical Data ◽  
Semantic Field ◽  
Traditional Values ◽  
Lexical Unit ◽  
Semantic Fields ◽  
Field Culture

Summary: The article deals with the analysis of the interpretational field of the basic lexical units which represent the meaning of the concept “woman” in English and Kyrgyz languages and cultures. Comparative – contrastive analytical data of the most frequently used in both languages variants of the interpretation of the concept “woman” have been given. The semantic fields of nuclear and nearnuclear meanings of the lexical units, transforming the notion of “woman” in English and Kyrgyz languages and also the place and role of these notions in cultures and philosophy of the nations on the basis of mentality and traditional values have been studied and described. The situations of the use of this or that variant of the meaning of lexical unit. A comparative study of the definitions of the word “woman’ in English and Kyrgyz languages have been given. Key words: concept, woman, interpretational field, notion, definition, semantic field, culture, language, linguoculture, transformation Аннотация: В статье рассматриваются интерпретационные поля основных лексических единиц, репрезентирующих значение концепта «женщина» в английской и кыргызской лингвокультурах. Приводятся сравнительно-сопоставительные аналитические данные наиболее употребительных в речи обоих языков вариантов интерпретации концепта «женщина». Изучены и описаны семантические поля ядерных и околоядерных значений лексических единиц, трансформирующих понятие «женщина» в английском и кыргызском языке, а также роль и место этих понятий в культурах и философии народов на основе менталитета и традиционных ценностей. Приводятся ситуации использования того или ино- го варианта значения лексической единицы, проведено сравнительное изучение определений слова «женщина» в английском и кыргызском языках. Ключевые слова: концепт, женщина, интерпретационное поле, понятие, определение, семантическое поле, культура, язык, лингвокультура, трансформация Аннотация: Макалада англис жана кыргыз тилдеринде жана маданияттарында «аял» концептинин маанисин репрезентациалаган негизги лексикалык бирдиктер каралат. «Аял» концептин эки тилдеги кѳп колдонулуучу интерпретациялоо варианттарынын аналитикалык салыштырма маалыматтары изил- делип берилген. Англис жана кыргыз тилдеринде «аял» түшүнүгүн трансформациялаган лексикалык бирдиктердин түп нуска жана ага жакындашкан маанилери иликтелип каралган. Берилген түшүнүктѳрдүн элдик философиясында жана маданиятында, менталитеттин жана салттын негизинде эл арасына кеӊири тараган, элдик тилде жана маданиятта ойногон ролу менен орду чагылдырылган. Ар түрдү ситацияларда колдонулуучу тиги же бул лексикалык бирдиктердин маанисинин варианттары каралган, «аял» деген сѳздун англис жана кыргыз тилдериндеги түшүндүрмѳлѳрү салыштырылып изилделген. Түйүндүү сѳздѳр: концепт, аял, интерпретациялоо мейкиндиги, түшүнүк, түшүндүрмѳ, семантикалык чѳйрѳ, маданият, тил, лингвомаданият, трансформациялоо

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