Electrolyte secretion from rabbit pancreas in vitro

A technic has been developed permitting direct collection of undiluted rabbit pancreatic secretion in vitro without vascular perfusion. The rates of secretion and output of electrolytes were comparable to those obtained in situ. When secretin was added, flow and bicarbonate concentration increased. Secretion in vitro ceased when inhibitors of glycolysis and aerobic metabolism were added to the bathing solution. The sodium concentration of the secretion exceeded that of the bathing solution in all but one observation. Potassium concentrations in secretion were linearly related (slope = 0.93) to the potassium concentration in the bath over a range of 5.8–12.0 mm. After 4–5 hr in vitro, the total carbon dioxide concentration of secretion had decreased while chloride concentration increased with no significant change in the rate of secretion. When secretory rate changed over a range of approximately 30–600 µliters/hr, chloride and carbon dioxide output varied directly with the rate of secretion. The osmolarity of the bathing solution and secretion were always equivalent. These results are incompatible with direct plasma filtration and bicarbonate-chloride exchange as the main mechanisms of pancreatic secretion.

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Acid-base regulation and blood gas transport following exhaustive exercise in an agnathan, the sea lamprey Petromyzon marinus

Journal of Experimental Biology ◽

10.1242/jeb.159.1.371 ◽

1991 ◽

Vol 159 (1) ◽

pp. 371-385

Author(s):

B. L. Tufts

Keyword(s):

Carbon Dioxide ◽

Oxygen Transport ◽

Petromyzon Marinus ◽

Carbon Dioxide Concentration ◽

Exhaustive Exercise ◽

Total Carbon ◽

Acid Base ◽

Carbon Dioxide Transport ◽

Arterial Blood

Exhaustive exercise in cannulated sea lampreys, Petromyzon marinus, resulted in a marked extracellular acidosis in the arterial blood which had both a respiratory and a metabolic component. Blood CO2 tension (PCO2) returned to control levels within an hour after exercise, but the metabolic acidosis had a somewhat longer time course and the extracellular pH (pHe) did not fully recover until the 4 h recovery sample. The magnitude and duration of the changes in both the plasma lactate concentration and the concentration of metabolic protons were very similar and the maximal proton deficit after exercise was, therefore, only 1.5 mequiv l-1. In contrast to the changes in pHe, there were no significant changes in the erythrocyte pH (pHi) following the exercise period. The regulation of pHi was apparently not adrenergically mediated, however, since addition of catecholamines to lamprey blood in vitro had no significant effect on pHi. In addition, the period of exhaustive exercise in vivo was not associated with any significant changes in the mean cellular hemoglobin concentration. The total carbon dioxide concentration in the arterial whole blood and true plasma were both significantly reduced after exercise, but the total carbon dioxide concentration within the erythrocytes was transiently increased. Finally, there was a marked decrease in the arterial PO2 immediately after exercise, which was associated with a significant reduction in the amount of oxygen bound to hemoglobin; however, within 30 min, these values had both returned to normal. The maintenance of pHi presumably contributes to the regulation of oxygen transport in lampreys and it may be particularly important during the brief period immediately after exercise when oxygen transport is clearly compromised. Although several studies have provided evidence that chloride/bicarbonate exchange limitations may exist in agnathan blood in vitro, the present results demonstrate that the characteristics of carbon dioxide transport and acid-base regulation after exercise in P. marinus are not markedly different from those in other lower vertebrates.

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Evaluation of nutrient content and in-vitro gas production of complete feed based on corn stover (Zea mays) supplemented by mimosa powder and myristic acid

Livestock and Animal Research ◽

10.20961/lar.v18i2.42998 ◽

2020 ◽

Vol 18 (2) ◽

pp. 191

Author(s):

Muchamad Muchlas ◽

Siti Chuzaemi ◽

Mashudi Mashudi

Keyword(s):

Carbon Dioxide ◽

Zea Mays ◽

Corn Stover ◽

Myristic Acid ◽

Block Design ◽

Gas Production ◽

Total Carbon ◽

Methane Gas ◽

In Vitro Gas Production

Objective: The purpose of this research was to evaluate the effect supplementation of mimosa powder as a source of condensed tannins and a single fatty acid, myristic acid, in a complete feed based on corn stover (Zea mays) using the in-vitro gas production method. This research has been carried out at the Animal Nutrition and Food Laboratory, Faculty of Animal Husbandry, Brawijaya University. The time of the research was conducted in August until December 2019.Methods: The experimental design used randomized complete block design by ANOVA consisting four treatments and three replications which were P1= a complete feed based on corn stover (Zea mays) as control Diet (CD) (40% corn stover + 60 % concentrate), P2= (CD) + Mimosa Powder(MP) 1.5 %/kg DM + myristic acid (MA)2% /kg DM, P3= CD + MP 1.5 % /kg DM + MA 3% /kg DM, and P4= CD + MP 1.5 %/kg DM + MA 4 %/kg DM.Results: The results showed that the treatments affected total gas production (p<0.01). The highest value for total gas production was found in P1 (86.67 ml/500 mg DM) and the lowest was found in P3 (73.30 ml/500 mg DM). The results showed that gas production decreased concurrently with the increase of MA level. In vitro methane gas and carbon dioxide production was showed different (p<0.05) from the control treatment. The lowest concentration of methane production was in P4 (82863.07 ppm) and the highest concentration was in treatment P1 86530.89 ppm. The highest total carbon dioxide content was P1 (436711.57 ppm) and the lowest concentration was P3 (350287.72 ppm).Conclusions: The results of the research concluded that the addition of mimosa powder and 3 different levels of myristic acid in a complete feed based on corn stover can increase the nutritional value of a complete feed and reduce the production of methane gas.

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Effects of step changes in pH on isometric tetanic tension of toad sartorius muscle

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y83-127 ◽

1983 ◽

Vol 61 (8) ◽

pp. 830-835 ◽

Cited By ~ 2

Author(s):

J. M. Renaud ◽

E. Don Stevens

Keyword(s):

Carbon Dioxide ◽

Steady State ◽

Rapid Change ◽

Carbon Dioxide Concentration ◽

Physiological Solution ◽

Acclimation Temperature ◽

Sartorius Muscle ◽

Bathing Solution ◽

Ph Change ◽

Tetanic Tension

The effect of a rapid change in pHe (pH of bathing solution) on the isometric tetanic tension developed by sartorius muscles of toads acclimated to 5 and 25 °C was measured at 5 and 25 °C. The pH was altered by changing the carbon dioxide concentration of a bicarbonate buffered physiological solution. Acclimation temperature did not modify the response to a rapid change in pH, but test temperature did. Following a pH decrease from 9.0 to 6.0, tetanic tension decreased at a faster rate at 5 °C than at 25 °C. A new steady state was reached in 15 min at 5 °C but in 40 min at 25 °C. Following a pH increase from 6.0 to 8.5, tetanic tension increased at a faster rate at 25 °C than at 5 °C. A new steady state was reached in 60 min at 5 °C but in 10 min at 25 °C. We conclude that the rate of carbon dioxide diffusion through the sartorius muscle is only one factor that determines how rapidly tetanic tension changes following the step change in pH, and that muscle resists pH change more effectively at higher temperatures.

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Inhibitory Component of the Resistance Reflex in the Locomotor Network of the Crayfish

Journal of Neurophysiology ◽

10.1152/jn.00178.2002 ◽

2002 ◽

Vol 88 (5) ◽

pp. 2575-2588 ◽

Cited By ~ 9

Author(s):

Morgane Le Bon-Jego ◽

Daniel Cattaert

Keyword(s):

Sensory Nerve ◽

Chloride Concentration ◽

Chordotonal Organ ◽

Bathing Solution ◽

Postsynaptic Potentials ◽

Inhibitory Pathways ◽

In Series ◽

Chloride Channel Blocker ◽

Inhibitory Components

The aim of this study was to investigate the inhibitory components of a resistance reflex in the walking system of the crayfish. This study was performed using an in vitro preparation of several thoracic ganglia including motor nerves and the proprioceptor that codes movements of the second joint (coxo-basipodite chordotonal organ—CBCO). Sinusoidal movements were imposed on the CBCO, and intracellular responses were recorded from levator (Lev) and depressor (Dep) motoneurons (MNs). We found that in MNs that oppose the imposed movements (e.g., the Lev MNs during the imposed downward movement), the response consists in a depolarization resulting from the summation of excitatory postsynaptic potentials (EPSPs). A movement in the opposite direction resulted in hyperpolarization during which inhibitory postsynaptic potentials (IPSPs) summated. The inhibitory pathway to each MN is oligosynaptic (i.e., composed of a small number of neurons in series) and involves spiking interneurons because it was blocked in the presence of a high-divalent cation solution. The IPSPs were mediated by a chloride conductance because their amplitude was sensitive to the chloride concentration of the bathing solution and because they were blocked by the chloride channel blocker, picrotoxin. Resistance reflex IPSPs related to single CBCO neurons could be identified. These unitary IPSPs were blocked in the presence of 3-mercapto-propionic acid, an inhibitor of gamma-amino-butyric acid (GABA) synthesis, indicating that they are mediated by GABA. In addition to this GABAergic pathway, electrical stimulation of the CBCO sensory nerve induced compound IPSPs that were blocked by glutamate pyruvate transaminase (GPT), indicating the presence of glutamatergic inhibitory pathways. These glutamatergic interneurons do not appear to be involved in the resistance reflex, however, as GPT did not block the unitary IPSPs. Functionally, the resistance reflex is mainly supported by movement-coding CBCO sensory neurons. We demonstrate that such movement-coding CBCO neurons produce both monosynaptic EPSPs in the MNs opposing imposed movements and oligosynaptic IPSPs in the antagonistic motoneurons. These results highlight the similarities between the inhibitory pathways in resistance reflex of the crayfish and in the stretch reflex of vertebrates mediated by Ia inhibitory interneurons.

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Comparison of two analyzers for measurement of plasma total carbon dioxide concentration in horses

American Journal of Veterinary Research ◽

10.2460/ajvr.74.8.1091 ◽

2013 ◽

Vol 74 (8) ◽

pp. 1091-1102

Author(s):

Peter D. Constable ◽

Stacy H. Tinkler ◽

Laurent. L. Couëtil

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Concentration ◽

Total Carbon

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Oxygenation of frog gastric mucosa in vitro

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.229.6.1510 ◽

1975 ◽

Vol 229 (6) ◽

pp. 1510-1513 ◽

Cited By ~ 10

Author(s):

GW Kidder ◽

CW Montgomery

Keyword(s):

Oxygen Consumption ◽

Gastric Mucosa ◽

Acid Secretion ◽

Normal Pressure ◽

Bathing Solution ◽

Hyperbaric Chamber ◽

Secretory Rate ◽

Co2 Diffusion ◽

Rate Of Oxygen Consumption

We have recently shown that 5% CO2/95% O2 in the serosal bathing solution, with 100% O2 in the mucosal solution, results in CO2-diffusion limitation of acid secretion in bullfrog gastric mucosa. Changing to 10% CO2/90% 02 on both surfaces doubles the acid secretory rate. We calculate that, were the rate of oxygen consumption to increase significantly as a result of secretory stimulation, the tissue would now be oxygen limited. This prediction is tested by raising the P02 by increasing the total pressure in a hyperbaric chamber. Since no change in acid secretory rate or potential difference was observed upon changing from PO2 = 0.9 to PO2 = 1.9 atm, we conclude that the tissue is not O2 limited at normal pressure. Decreasing PO2 below 0.9 atm, by contrast, decreases the acid secretory rate and raises both PD and resistance. We infer that the rate of oxygen consumption did not rise significantly when acid secretion was increased by supplying sufficient CO2.

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Relationship between serum total carbon dioxide concentration and bicarbonate concentration in patients undergoing hemodialysis

Kidney Research and Clinical Practice ◽

10.23876/j.krcp.19.126 ◽

2020 ◽

Vol 39 (4) ◽

pp. 441-450

Author(s):

Keiji Hirai ◽

Susumu Ookawara ◽

Junki Morino ◽

Saori Minato ◽

Shohei Kaneko ◽

...

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Concentration ◽

Total Carbon ◽

Bicarbonate Concentration

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Organic Acids Interfere in the Measurement of Carbon Dioxide Concentration by the Kodak Ektachem 700

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456329202900117 ◽

1992 ◽

Vol 29 (1) ◽

pp. 105-108 ◽

Cited By ~ 5

Author(s):

Nader Rifai ◽

John Hyde ◽

Mariet Iosefsohn ◽

Allen M. Glasgow ◽

Steven J Soldin

Keyword(s):

Carbon Dioxide ◽

Organic Acids ◽

Carbon Dioxide Concentration ◽

Total Carbon ◽

Blood Gas ◽

Total Plasma ◽

Bicarbonate Concentration ◽

Significant Discrepancy ◽

Maple Syrup ◽

Urine Disease

A significant discrepancy was noted in our laboratory between the total plasma carbon dioxide concentration measured by the Kodak Ektachem 700 and the bicarbonate concentration derived from the Corning 170 pH/Blood Gas analyser in an 8-day-old patient. The concentration of total carbon dioxide was 18 mmol/L while the derived bicarbonate was 13 mmol/L. The patient was eventually diagnosed as maple syrup urine disease. This finding led us to examine the effect of various organic acids on the measurement of carbon dioxide by the Ektachem 700. Several interfered significantly. Clinicians should be aware that when organic acid concentrations are increased, the Ektachem 700 total carbon dioxide result may be falsely raised.

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