The Effect of Anoxemia in Normal Dogs Before and After Denervation of the Carotid Sinuses

Gemmill, Chalmers L.; Reeves, David

doi:10.1152/ajplegacy.1933.105.2.487

Cited by 42 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference between the response before and after denervation was significant, 0O025 > P > 0.01 and confirms the results obtained by in the new-born rabbit. These results also resemble those reported by Gemmill & Reeves (1933), Davenport, Brewer, Chambers & Goldschmidt (1947) and by Watt, Dumke & Comroe (1943) in dogs before and after chronic carotid chemoreceptor denervation.…”

Section: Lower Trace)supporting

confidence: 91%

The effects of hypoxia in the new‐born lamb before and after denervation of the carotid chemoreceptors*

Purves¹

1966

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Twenty-seven unanaesthetized new-born lambs, 6 hr-10 days old, responded to two levels of inspired oxygen, 125 and 110 mm Hg (alveolar CO2 being controlled) with a sustained increase in minute ventilation (1), a small increase in heart rate and a less consistent rise in systemic blood pressure.2. An increase in v was observed when arterial oxygen tension (Pa, 02) had fallen by 6-15 mm Hg. There appeared to be no fixed threshold of Pa,°a t which ventilation started to increase.3. The increase in ventilation caused by these levels of hypoxia was significantly and directly related to the age of the lamb and to its control alveolar C02.4. More severe hypoxia caused a progressive increase in v until Pa, 02 was about 25 mm Hg when respiration failed. This increase at P., 02 > 25 mm Hg was markedly potentiated when alveolar PCO2 (PA,co2) was increased and abolished after bilateral denervation of the carotid chemoreceptors.5. Significant (> 10%) left-to-right shunts were found in ten out of twelve lambs lightly anaesthetized with pentobarbitone sodium, breathing air. Hypoxia diminished the left-to-right pressure gradient largely by its pressor effect on the pulmonary circulation. When inspired 02 tension (P, 02) was 70 mm Hg, all seven lambs studied showed a reversal of the pressure gradient and evidence of right-to-left shunts (11-42 %) across the ductus arteriosus.6. The implications of these findings have been discussed with reference * This study was supported in part by USPHS grant HE-06285.

show abstract

Section: Lower Trace)supporting

confidence: 91%

The effects of hypoxia in the new‐born lamb before and after denervation of the carotid chemoreceptors*

Purves¹

1966

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Our estimate for the peripheral drive can be compared with other studies which have estimated it by various other methods; e.g. it made no contribution in unanaesthetized dogs (Gemmill & Reeves, 1933) and anaesthetized rabbits (Kiwull, Wiemer & Schone, 1972), contributed 10 % (Katsaros, 1965) and 20-50 % Berkenbosch, Van Dissel, Olievier, De Goede & Herringa, 1979) in anaesthetized cats, and 12 % (Gelfand & Lambertsen, 1973) and more than 15 % (Crawford & Severinghaus, 1978) in man. Thus there seems to be a species difference in the contribution of the 233 S. KUWANA AND T. NATSUI peripheral chemoreceptors.…”

Section: Relationship Between Pthco and [H+] The Linear Relationshimentioning

confidence: 69%

“…intact or denervated. The c.s.n.s on both sides were sectioned at the level of their emergence from the glossopharyngeal nerves; denervation was confirmed by observing the respiratory response to pure nitrogen inhalation (Gemmill & Reeves, 1933). Before starting the experimental observations, usually more than 1 hr had to be allowed for subsidence of neurogenic hypertension brought about by the simultaneous denervation of the carotid sinus baroreceptors.…”

Section: Generalmentioning

confidence: 99%

Effect of arterial [H+] on threshold PCO2 of the respiratory system in vagotomized and carotid sinus nerve denervated cats.

Kuwana¹,

Natsui²

1981

The Journal of Physiology

View full text Add to dashboard Cite

Phrenic nerve discharges were recorded as an output of respiratory activity in anaesthetized, vagotomized cats immobilized by gallamine and artificially ventilated with room air. 2. With the carotid sinus nerve (c.s.n.) intact or denervated, PcO2 threshold levels (Pth, CO2) were determined at arterial pH, varied between 7.0 and 7.6 ([H+] 25-100 nM) by successive intravenous infusions of 0.5 N-HCl or 1.0 M-NaHCO3. Ventilation was increased stepwise to induce a successive decrease in end-tidal PCO2. Pth, CO2 was defined as the level of end-tidal PCO2 at which phrenic discharges ceased. 3. With the c.s.n. intact, Pth, CO2 decreased linearly upon increasing arterial [H+]. The mean regression line, calculated from seven cats, was Pth, CO2 =-0.37 [H+] + 34.33. A similar inverse relationship was observed with the c.s.n. denervated. However, the slope of the regression line was significantly smaller, the mean regression line/eleven cats) being Pth,CO2 =-0.18 [H+]+ 35.06. 4. The relative contributions of arterial [H+] and PCO2 in stimulating the peripheral and central chemoreceptors could be estimated quantitatively. Arterial [H+] appears to be almost equally effective on both peripheral and central chemoreceptors; PCO2 acts exclusively on the central chemoreceptors. 5. Thus, the additive theory regarding the induction of respiratory activity by arterial [H+] and PCO2 was confirmed. In addition, the H+ drive was shown to be able to affect respiratory activity even in the absence of the peripheral chemoreceptors.

show abstract

“…The combined peripheral chemoreceptor-and central nervous system-mediated responses (the latter take at least a minute to develop) (10) were tested by continuous inhalation of 1% CO in 40% 02. To confirm the validity of this approach, and to elucidate the mechanisms involved in the ventilatory responses that were observed, additional studies were done.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the ventilatory response to carbon monoxide.

Santiago¹,

Edelman²

1976

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T The effects of carbon monoxide on ventilation were studied in unanesthetized goats. Responses to single breaths of 10-25% CO in 02, which rapidly raised carboxyhemoglobin (COHb) from 5 to 60%, were considered to reflect peripheral chemoreceptor-mediated reflexes whereas responses to continuous inhalation of 1% CO in 02, which slowly raised COHb from 0 to 60%, were considered to reflect both peripheral chemoreceptor and nonperipheral chemoreceptor mechanisms. In each of six goats, single breaths of CO failed to elicit any immediate ventilatory response.However, slow buildup of carboxyhemoglobinemia in the same animals always elicited ventilatory stimulation (from a mean of 7.43 to 16.02 liter/min, P < 0.001) beginning 5-6 min after onset of 1% CO in 02 inhalation when COHb saturation reached 50-60%. In eight studies of six animals HCOs-concentration fell (from 21.3 to 15.8 meq/liter; P <0.001) and lactate concentration rose (from 2.5 to 4.2 meq/liter; P < 0.05) in the cisternal cerebrospinal fluid during the CO-induced hyperpnea. Additional studies ruled out ventilatory stimulation from left heart failure or enhanced chemosensitivity to carbon dioxide. Although the delayed hyperpnea was associated with a hyperdynamic cardiovascular response to CO, blockade of these circulatory effects with propranolol (2 mg/kg) failed to abolish the delayed hyperpnea; however, the propranolol did unmask an element of ventilatory depression which preceded the hyperpnea. Conclusions were: (a) hyperventilation in response to CO inhalation is not mediated by the carotid bodies; (b) the delayed hyperpnea in response to CO inhalation is primarily due to braincerebrospinal fluid acidosis; (c) mobilization of body CO2 stores due to the circulatory response to CO may obscure an initial depression of ventilation by CO. INTRODUCTIONThe increase in ventilation caused by reduction in arterial 02 tension is well known and clearly ascribed

show abstract

The Effect of Anoxemia in Normal Dogs Before and After Denervation of the Carotid Sinuses

Cited by 42 publications

References 0 publications

The effects of hypoxia in the new‐born lamb before and after denervation of the carotid chemoreceptors*

The effects of hypoxia in the new‐born lamb before and after denervation of the carotid chemoreceptors*

Effect of arterial [H+] on threshold PCO2 of the respiratory system in vagotomized and carotid sinus nerve denervated cats.

Mechanism of the ventilatory response to carbon monoxide.

Contact Info

Product

Resources

About