Mechanisms of Carbon Dioxide and pH Effects on Metabolism

Nahas, Gabriel G.

doi:10.1007/978-1-4612-9831-1_9

Cited by 7 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Increased glucose concentration was also observed in blood collected from the orbital sinus in rats subjected to CO~/02 inhalation when compared with that collected from rats subjected to ether inhalation (5). Both of these findings are consistent with previous observations that plasma catecholamines are increased during CO, inhalation (11,12,16). Human volunteers indicated increasing levels of discomfort associated with breathing varying concentrations of CO2 as the concentration of CO~ increased (4).…”

Section: Discussionsupporting

confidence: 88%

“…Increased glucose concentration was also observed in blood collected from the orbital sinus in rats subjected to CO~/02 inhalation when compared with that collected from rats subjected to ether inhalation (5). Both of these findings are consistent with previous observations that plasma catecholamines are increased during CO, inhalation (11,12,16 (12), so it is unlikely that the release is the result of a fear or pain mechanism alone. CO2 has multiple effects, including the ability to directly increase cerebral blood flow by a vasodilatative mechanism, to excite neurons (especially the reticuloactivating system), and to decrease the intracellular pH (12).…”

Section: Introductionsupporting

confidence: 90%

“…Alterations in electrolyte values have been seen in some earlier studies. CO, inhalation results in respiratory acidosis (11,13,17). Dogs subjected to 30 min of inhalation of 30% C02 had an increase in ultrafilterable (ionized) calcium.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Carbon Dioxide Inhalation on Hematology, Coagulation, and Serum Clinical Chemistry Values in Rats

Walter

1999

Toxicol Pathol

View full text Add to dashboard Cite

Blood samples from adult male and female Charles River Cr1:CD® (SD) BR rats were collected at weekly intervals for 4 wk to evaluate the effects of inhalation of an anesthetic dose of carbon dioxide (CO 2 ) or of a carbon dioxide-oxygen mixture (CO 2 /O 2 ) on hematology, coagulation, and serum biochemistry values. During the first 3 wk of the study, rats were assigned to 1 of 3 groups and were bled from the orbital sinus once weekly. Prior to the blood collection, rats in group 1 were exposed to room air only, rats in group 2 received CO 2 /O 2 (approximately 66%:34% CO 2 :O 2 ) by inhalation, and rats in group 3 received 100% CO 2 by inhalation. In the rats exposed to CO 2 /O 2 or CO 2 , leukocyte counts, lymphocyte counts, and glucose values were higher, and aspartate aminotransferase, creatine kinase, and calcium values were lower compared with those of rats exposed to room air only. Rats exposed to 100% CO 2 had slightly (but statistically significant) lower mean corpuscular hemoglobin concentration when compared with rats exposed only to room air. During week 4, all rats were reassigned to 1 of 2 groups and were bled terminally via closed cardiac puncture following exposure to either CO 2 /O 2 or CO 2 . Increased lymphocyte counts (males only) and glucose and chloride concentrations were noted for rats exposed to CO 2 /O 2 compared with those exposed to CO 2 . These alterations reiterate the importance of comparing clinical pathology values to those of concurrent control groups that have experienced blood collection under identical conditions in order to avoid potential errors in the interpretation of data.

show abstract

Section: Discussionsupporting

confidence: 88%

“…Increased glucose concentration was also observed in blood collected from the orbital sinus in rats subjected to CO~/02 inhalation when compared with that collected from rats subjected to ether inhalation (5). Both of these findings are consistent with previous observations that plasma catecholamines are increased during CO, inhalation (11,12,16 (12), so it is unlikely that the release is the result of a fear or pain mechanism alone. CO2 has multiple effects, including the ability to directly increase cerebral blood flow by a vasodilatative mechanism, to excite neurons (especially the reticuloactivating system), and to decrease the intracellular pH (12).…”

Section: Introductionsupporting

confidence: 90%

See 1 more Smart Citation

Effects of Carbon Dioxide Inhalation on Hematology, Coagulation, and Serum Clinical Chemistry Values in Rats

Walter

1999

Toxicol Pathol

View full text Add to dashboard Cite

show abstract

“…The latter may be related to the relative degree of sympathoadrenal activation and acidemia elicited by hypercapnia, as these effects would have opposing actions on V O 2 (24). We found a drop in V O 2 with hypercapnia in the light phase of the chronic exposure, when activity was low and, similar to Peever and Stephenson (25), during the acute experiments when rats were quiet.…”

Section: Discussionsupporting

confidence: 66%

Circadian pattern of ventilation during acute and chronic hypercapnia in conscious adult rats

Seifert

Mortola

2002

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Seifert, Erin L., and Jacopo P. Mortola. Circadian pattern of ventilation during acute and chronic hypercapnia in conscious adult rats. Am J Physiol Regulatory Integrative Comp Physiol 282: R244-R251, 2002; 10.1152/ajpregu. 00290.2001.-Because metabolism is a determinant of the ventilatory chemosensitivity, we tested the hypothesis that the ventilatory response to acute and prolonged hypercapnia is adjusted to the circadian oscillations in oxygen consumption (V O2). Adult rats were instrumented for measurements of body temperature (Tb) and activity by telemetry. Pulmonary ventilation (V E) was measured by the barometric method and V O2 by the flow-through method. In the acute experiments, 16 conscious rats entrained to a 12:12-h light (L)-dark (D) cycle (lights on 7:00 AM) were exposed to air, 2%, and then 5% CO2 in normoxia (30-45 min each) at 11:00 AM and 11:00 PM. In a separate group of seven rats, simultaneous recordings of all variables were made continuously for 3 consecutive days in air followed by 3 days in 2% CO2 in normoxia, in a 12:12-h L-D cycle (lights on 7:00 AM). In air, all variables were significantly higher at night, whether rats were studied acutely or chronically. Acute CO2 exposure had similar significant effects at 11:00 AM and 11:00 PM on V E (ϳ25 and 100% increase with 2 and 5% CO2, respectively) and V O2 (ϳ8% drop with 5% CO2), such that the hyperventilatory response (% increase in V E/V O2 from air) was similar at both times. Chronic CO2 breathing increased V E at all times of the day, but less so during the L phase (ϳ15 vs. 22% increase in L and D, respectively), when activity was lower. However, V O2 was reduced from the air level (ϳ10% drop) in the L, such that the V E/V O2 response was similar between L and D. The same result was obtained when the V E/V O2 response was compared between the L and D phases for the same level of activity. These results suggest that, throughout the day, the hypercapnic hyperpnea, whether during acute or prolonged CO2, is perfectly adjusted to the metabolic level.control of breathing; chemosensitivity; barometric method; oxygen consumption IN MAMMALS AND BIRDS, blood gas homeostasis depends on the matching of pulmonary ventilation (V E) to metabolism. Indeed, a close coupling between V E and oxygen consumption (V O 2 ) has been found under a variety of conditions where V O 2 is either raised or lowered (20). Variations in metabolism are also associated with changes in V E chemosensitivity (19). A higher V O 2 , as during muscular exercise (35) or cold exposure (12), is accompanied by a greater absolute increase in V E in response to acute hypoxia or hypercapnia, whereas reflex hyperpnea is lower whenVO 2 is reduced, such as with myxedema (36) or semi-starvation (6). Hence, the V E chemoreflex response seems to track V O 2 . This would tend to minimize fluctuations in blood gases in normoxia and when chemosensory drive is elevated.Oxygen consumption presents a circadian oscillation. Although the daily high values of V O 2 generally occur when an animal i...

show abstract

“…Other mediators, such as catecholamines, serotonin, angiotensin, and "tissue CRF," may also play a certain role under certain conditions (9). Nahas (13) established that the increased pCO2 and/or acidosis can influence both catecholamine production and activity. Probably this mechanism acts mainly in our experimental procedure with a threefold breath-holding.…”

Section: Discussionmentioning

confidence: 99%

Human Growth Hormone, Cortisol, and Acid-Base Balance Changes After Hyperventilation and Breath-Holding

Djarova¹,

Ilkov²,

Varbanova³

et al. 1986

Int J Sports Med

View full text Add to dashboard Cite

The purpose of this study was to investigate the effects of hyperventilation and breath-holding on hormonal activity and the acid-base balance in men. Three different experimental procedures were carried out with 11 trained subjects aged 24.5 years. In experiment I, all subjects performed hyperventilation for 3 min maintaining a paced ventilation of 47 l X min-1. In experiment II, they performed a threefold maximal voluntary breath-holding, separated by 1-min periods of normal breathing. Experiment III consisted of a combination of hyperventilation immediately followed by maximal voluntary breath-holding. Capillary blood samples were taken for determination of pO2, pCO2, and pH. Venous blood samples were drawn before and at the 5th and 30th min after the cessation of the applied procedure for RIA determination of human growth hormone (HGH) and cortisol. During the last 15 s of hyperventilation, pO2 increased to 89.4 +/- 16.2 mm Hg, pCO2 decreased to 19.6 +/- 1.6 mm Hg, and pH increased to 7.652 +/- 0.041. During the last 15 s of the third breath-holding, the results were pO2 = 58.0 +/- 5.1, pCO2 = 45.7 +/- 3.7, and pH = 7.367 +/- 0.053. In experiment III, the mean values were pO2 = 42.6 +/- 7.9 mmHg, pCO2 = 39.2 +/- 4.6 mmHg, and pH = 7.320 +/- 0.024. A significant hormonal response after the applied experimental procedures was found for HGH (1.5- to 5.56-fold increase) and cortisol (1.5- to 2.2-fold increase).(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

Mechanisms of Carbon Dioxide and pH Effects on Metabolism

Cited by 7 publications

References 28 publications

Effects of Carbon Dioxide Inhalation on Hematology, Coagulation, and Serum Clinical Chemistry Values in Rats

Effects of Carbon Dioxide Inhalation on Hematology, Coagulation, and Serum Clinical Chemistry Values in Rats

Circadian pattern of ventilation during acute and chronic hypercapnia in conscious adult rats

Human Growth Hormone, Cortisol, and Acid-Base Balance Changes After Hyperventilation and Breath-Holding

Contact Info

Product

Resources

About