Interactions between cutaneous ion-exchange mechanisms and acid–base balance in amphibians

1989 ◽  
Vol 67 (12) ◽  
pp. 3070-3077 ◽  
Author(s):  
Daniel F. Stiffler
Keyword(s):  
Ion Exchange ◽  
Ion Transport ◽  
Extracellular Fluid ◽  
Ambystoma Tigrinum ◽  
Acid Base Balance ◽  
Acid Base ◽  
Homeostatic Process ◽  
Base Balance ◽  
Net Flux ◽  
Exercise Induced

It has been suspected for over 50 years that amphibian ion exchange involves independent transport of Na+ and Cl− in an inward direction across the skin in exchange for acidic cations and basic anions, respectively. Although a role for such exchange mechanisms has obvious utility in acid–base balance, their participation in this homeostatic process has only recently been documented. We now know that in aquatic Ambystoma tigrinum, the presence of NaCl in the water bathing the skin is required for acid–base regulatory responses to hypercapnia and exercise-induced lactacidosis. Acidotic and alkalotic conditions in the animals' extracellular fluid cause changes in both Na+ and Cl− influx and net flux which are consistent with a role for ion transport in acid–base balance. These processes appear to be under the control of both catecholamines and interrenal steroids.

scholarly journals Extracellular Acid-Base Balance and Ion Transport Between Body Fluid Compartments

Physiology ◽  
2017 ◽  
Vol 32 (5) ◽  
pp. 367-379 ◽  
Author(s):  
Julian L. Seifter ◽  
Hsin-Yun Chang
Keyword(s):  
Ion Transport ◽  
Ph Regulation ◽  
Extracellular Fluid ◽  
Transport Processes ◽  
Electrolyte Balance ◽  
Ph Homeostasis ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Fluid Compartments

Clinical assessment of acid-base disorders depends on measurements made in the blood, part of the extracellular compartment. Yet much of the metabolic importance of these disorders concerns intracellular events. Intracellular and interstitial compartment acid-base balance is complex and heterogeneous. This review considers the determinants of the extracellular fluid pH related to the ion transport processes at the interface of cells and the interstitial fluid, and between epithelial cells lining the transcellular contents of the gastrointestinal and urinary tracts that open to the external environment. The generation of acid-base disorders and the associated disruption of electrolyte balance are considered in the context of these membrane transporters. This review suggests a process of internal and external balance for pH regulation, similar to that of potassium. The role of secretory gastrointestinal epithelia and renal epithelia with respect to normal pH homeostasis and clinical disorders are considered. Electroneutrality of electrolytes in the ECF is discussed in the context of reciprocal changes in Cl−or non Cl−anions and [Formula: see text].

scholarly journals Photobiomodulation 30 min or 6 h Prior to Cycling Does Not Alter Resting Blood Flow Velocity, Exercise-Induced Physiological Responses or Time to Exhaustion in Healthy Men

2021 ◽  
Vol 11 ◽  
Author(s):  
Yago Medeiros Dutra ◽  
Gabriel Machado Claus ◽  
Elvis de Souza Malta ◽  
Daniela Moraes de Franco Seda ◽  
Anderson Saranz Zago ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Femoral Artery ◽  
Blood Flow Velocity ◽  
Time To Exhaustion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Exercise Induced ◽  
Plasma Nitrite

PurposeThe aim of the current study was to investigate the effects of photobiomodulation therapy (PBMT) applied 30 min or 6 h prior to cycling on blood flow velocity and plasma nitrite concentrations at rest, time to exhaustion, cardiorespiratory responses, blood acid-base balance, and K+ and lactate concentrations during exercise.MethodsIn a randomized, crossover design, 13 healthy untrained men randomly completed four cycling bouts until exhaustion at the severe-intensity domain (i.e., above respiratory compensation point). Thirty minutes or 6 h prior to the cycling trials, participants were treated with PBMT on the quadriceps, hamstrings, and gastrocnemius muscles of both limbs using a multi-diode array (11 cm × 30 cm with 264 diodes) at doses of 152 J or a sham irradiation (with device turned off, placebo). Blood samples were collected before and 30 min or 6 h after treatments to measure plasmatic nitrite concentrations. Doppler ultrasound exams of the femoral artery were also performed at the same time points. Cardiorespiratory responses, blood acid-base balance, and K+ and lactate concentrations were monitored during exercise sessions.ResultsPBMT did not improve the time to exhaustion (p = 0.30). At rest, no differences were found in the peak systolic velocity (p = 0.97) or pulsatility index (p = 0.83) in the femoral artery, and in plasma nitrite concentrations (p = 0.47). During exercise, there were no differences for any cardiorespiratory response monitored (heart rate, p = 0.15; oxygen uptake, p = 0.15; pulmonary ventilation, p = 0.67; carbon dioxide output, p = 0.93; and respiratory exchange ratio, p = 0.32), any blood acid-base balance indicator (pH, p = 0.74; base excess, p = 0.33; bicarbonate concentration, p = 0.54), or K+ (p = 0.22) and lactate (p = 0.55) concentrations.ConclusionsPBMT at 152 J applied 30 min or 6 h before cycling at severe-intensity did not alter resting plasma nitrite and blood flow velocity in the femoral artery, exercise-induced physiological responses, or time to exhaustion in healthy untrained men.

Aldosterone inhibits HCO-3 absorption via a nongenomic pathway in medullary thick ascending limb

2002 ◽  
Vol 283 (4) ◽  
pp. F699-F706 ◽  
Author(s):  
David W. Good ◽  
Thampi George ◽  
Bruns A. Watts
Keyword(s):  
Actinomycin D ◽  
Renal Tubule ◽  
Extracellular Fluid ◽  
Transepithelial Transport ◽  
Thick Ascending Limb ◽  
The Novel ◽  
Acid Base Balance ◽  
Acid Base ◽  
Medullary Thick Ascending Limb ◽  
Base Balance

Rapid actions of aldosterone that are independent of transcription and translation have been described in a variety of cells; however, whether nongenomic pathways mediate aldosterone-induced regulation of renal tubule transport has not been determined. We report here that aldosterone induces rapid (<3.5 min) inhibition of HCO[Formula: see text] absorption in the medullary thick ascending limb (MTAL) of the rat. This inhibition is observed over the physiological range of hormone concentrations (IC50 ≃ 0.6 nM) and is not affected by pretreatment with actinomycin D (12.5 μg/ml), cycloheximide (40 μg/ml), or spironolactone (10 μM). The glucocorticoids dexamethasone, cortisol, and corticosterone (1 or 500 nM) did not affect HCO[Formula: see text]absorption in the absence or presence of carbenoxolone. Thus the specificity of rapid aldosterone action is not dependent on 11β-hydroxysteroid dehydrogenase activity. The inhibition by aldosterone is additive to inhibition by angiotensin II and vasopressin, indicating that these factors regulate MTAL transport through distinct pathways. These results demonstrate that aldosterone inhibits HCO[Formula: see text] absorption in the MTAL via a pathway that is rapid, highly selective, independent of transcription and protein synthesis, and not mediated through the classic mineralocorticoid receptor. The results establish a role for nongenomic pathways in mediating aldosterone-induced regulation of transepithelial transport in the mammalian kidney. The novel action of aldosterone to inhibit luminal acidification in the MTAL may play a role in enabling the kidney to regulate acid-base balance independently of Na+ balance and extracellular fluid volume.

Acid-base and ionic balance in Ambystoma tigrinum and Necturus maculosus during hypercapnia

1983 ◽  
Vol 245 (5) ◽  
pp. R689-R694 ◽  
Author(s):  
D. F. Stiffler ◽  
B. L. Tufts ◽  
D. P. Toews
Keyword(s):  
Prolonged Exposure ◽  
Epithelial Transport ◽  
Ambystoma Tigrinum ◽  
Ionic Balance ◽  
Acid Base Balance ◽  
Acid Base ◽  
Necturus Maculosus ◽  
Arterial Ph ◽  
Partial Pressure Of Co2 ◽  
Base Balance

The aquatic urodeles Ambystoma tigrinum and Necturus maculosus responded to hypercapnia quite differently. A. tigrinum, after 2-h exposure to 22 Torr partial pressure of CO2 (PCO2), decreased arterial pH (pHa) from 7.85 to 7.32 and increased arterial pressure of CO2 (PaCO2) to 26 Torr. Plasma [HCO-3] [( HCO-3]pl) remained constant at about 17 mM. Prolonged exposure (24 h) led to a 26% extracellular compensation as pHa rose to 7.46 while [HCO-3]pl increased to 24 mM. Plasma [K+] increased and [Cl-] decreased while [Na+] remained unchanged. Recovery in normocapnic water reversed these changes. N. maculosus did not display similar compensatory changes. Two-hour exposure to 17 Torr PCO2 resulted in a decline of pHa from 7.66 to 7.24, which was not compensated (pHa = 7.19) after 24 h. There were no significant changes in plasma [Na+], [K+], [Cl-], or [HCO-3]. The pHa decline reversed after recovery in normocapnic water, however. The fact that compensation for hypercapnic in A. tigrinum was accompanied by changes in Cl- and K+ concentrations may indicate the participation of epithelial transport mechanisms involving these ions in acid-base balance.

Distribution of H+ and HCO3 minus between CSF and blood during metabolic acidosis in dogs

1975 ◽  
Vol 228 (4) ◽  
pp. 1134-1140 ◽  
Author(s):  
EG Pavlin ◽  
TF Hornbein
Keyword(s):  
Metabolic Acidosis ◽  
Extracellular Fluid ◽  
Acid Base Balance ◽  
Ion Distribution ◽  
Acid Base ◽  
Control Series ◽  
Base Balance ◽  
Active Ion Transport ◽  
Arterial Plasma ◽  
Lumbar Cerebrospinal Fluid

To determine whether the regulation of brain extracellular fluid acid-base balance is by active ion transport or passive distribution, changes in cisternal and lumbar cerebrospinal fluid (CSF) (H+) and (HCO3 minus) were assessed in five dogs with normal acid-base status and in six dogs during metabolic acidosis. Both groups were mechanically ventilated to maintain a constant PaCO2. The pH, PCO2, (HCO3 minus), and (lactate) in CSF and arterial plasma and the CSF/plasma DC potential difference were determined at intervals, and the electrochemical potential differnces (mu) for H+ and HCO3 minus were calculated. Following control measurements at pHa equal to 7.40, metabolic acidosis was induced by infusion of 0.6 N HCl. Measurements were made 0, 3, 4.5, and 6 h thereafter and at 0, 3, and 6 h in the control series. A steady state for ion distribution was reached by 4.5 h. In the control series at 6 h the values of mu for H+ and HCO3 minus were within minus 0.2 and +0.5 mV of initial values at the cistern and +0.1 and +0.9 mV at the lumbar site. During metabolic acidosis, the 6-h values at the cistern returned to 0.0 and +0.7 mV of control for muH+ and muHCO3 minus while lumbar values returned to +0.5 and minus 0.4 mV. The closeness of these 6-h values of mu to control is compatible with passive distribution of H+ and HCO3 minus between CSF and blood.

Supramaximal exercise after training-induced hypervolemia. I. Gas exchange and acid-base balance

1987 ◽  
Vol 62 (5) ◽  
pp. 1944-1953 ◽  
Author(s):  
H. J. Green ◽  
R. L. Hughson ◽  
J. A. Thomson ◽  
M. T. Sharratt
Keyword(s):  
Gas Exchange ◽  
Carrying Capacity ◽  
Minute Ventilation ◽  
Hemoglobin Concentration ◽  
O2 Consumption ◽  
Supramaximal Exercise ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Exercise Induced

The effect of an exercise-induced reduction in blood O2-carrying capacity on ventilatory gas exchange and acid-base balance during supramaximal exercise was studied in six males [peak O2 consumption (VO2peak), 3.98 +/- 0.49 l/min]. Three consecutive days of supramaximal exercise resulted in a preexercise reduction of hemoglobin concentration from 15.8 to 14.0 g/dl (P less than 0.05). During exercise (120% VO2peak) performed intermittently (1 min work to 4 min rest); a small but significant (P less than 0.05) increase was found for both O2 consumption (VO2) (l X min) and heart rate (beats/min) on day 2 of the training. On day 3, VO2 (l/min) was reduced 3.2% (P less than 0.05) over day 1 values. No changes were found in CO2 output and minute ventilation during exercise between training days. Similarly, short-term training failed to significantly alter the changes in arterialized blood PCO2, pH, and [HCO-3] observed during exercise. It is concluded that hypervolemia-induced reductions in O2-carrying capacity in the order of 10–11% cause minimal impairment to gas exchange and acid-base balance during supramaximal non-steady-state exercise.

scholarly journals The effect of 60 km endurance exercise on serum electrolytes and acid–base balance in the Žemaitukai horses

2020 ◽  
Vol 89 (2) ◽  
pp. 125-131
Author(s):  
Indrė Poškienė ◽  
Vida Juozaitienė ◽  
Renata Gruodytė ◽  
Ramūnas Antanaitis
Keyword(s):  
Carbon Dioxide ◽  
Endurance Exercise ◽  
Base Excess ◽  
Haemoglobin Concentration ◽  
Extracellular Fluid ◽  
Total Carbon ◽  
Acid Base Balance ◽  
Acid Base ◽  
Blood Indices ◽  
Base Balance

The Lithuanian Žemaitukai horse breed is one of the oldest in Europe. Currently, there is a lack of information about the effect of endurance competition on blood indices and acid–base balance in the Žemaitukai horses. The aim of this study was to evaluate the effect of endurance exercise on the acid–base balance and electrolyte indicators of the Žemaitukai horses in an official endurance competition. In total, 48 horses of the Žemaitukai breed competed in endurance competitions over the same distance (60 km). Samples were taken before and immediately after the exercise. The following indicators were analysed: the hydrogen potential (pH), partial carbon dioxide pressure (pCO2), partial oxygen pressure (pO2), base excess in blood (BE), base excess in the extracellular fluid [BE (ecf)], cHCO3 (bicarbonate), cSO2 (oxygen saturation), tCO2 (blood total carbon dioxide), haematocrit (HCT), haemoglobin concentration (cHgb), sodium (Na), potassium (K), calcium (Ca), chlorides (Cl), and lactate (Lac). Increase in pH showed adaptation of the horse metabolism to exercise. Blood changes were caused by the development of dehydration and metabolic alkalosis. According to Lac results, all horses were fit and tolerated well physical activity. The exercise did not significantly affect the demand for minerals. Based on the results obtained, it can be stated that horses of the Žemaitukai breed are suitable for endurance competing.

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