Muscle ammonia stores are not determined by pH gradients
1Department of Zoology, University of British Columbia, V6T 2A9, Vancouver, British Columbia, Canada.
Fish Physiology and Biochemistry
|November 15, 2013
Summary
Ammonia distribution in trout muscle doesn't follow pH gradients, indicating cell membranes are permeable to ammonium. Intracellular ammonia stores are not solely determined by pH differences.
Area of Science:
- Physiological and biochemical responses of fish to environmental stressors.
- Cellular transport mechanisms and membrane permeability.
Background:
- Non-ionic diffusion theory predicts ammonia distribution based on pH gradients.
- Previous studies suggest pH gradients influence ammonia levels in aquatic organisms.
Purpose of the Study:
- To investigate ammonia distribution in rainbow trout white muscle and plasma.
- To determine if ammonia distribution aligns with transmembrane pH gradients under resting and exercise conditions.
Main Methods:
- Comparison of ammonia and (14)C-DMO distribution in rainbow trout.
- Measurements taken at rest and after exhaustive exercise.
Main Results:
- Intracellular ammonia levels significantly exceeded predictions from pH gradients.
- Calculated equilibrium potentials for ammonium ions were close to resting membrane potentials.
Conclusions:
- Ammonium ions (NH4+) are permeable across fish white muscle cell membranes.
- Intracellular ammonia storage is not solely dictated by transmembrane pH gradients.
More Related Videos
11:54Optical Quantification of Intracellular pH in Drosophila melanogaster Malpighian Tubule Epithelia with a Fluorescent Genetically-encoded pH Indicator
Published on: August 11, 2017
9.5K
09:40Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle
Published on: January 19, 2017
10.8K
Related Concept Videos
01:24Muscle Recovery and Fatigue
4.5K
Muscle fatigue refers to the decline in a muscle's ability to maintain the force of contraction after prolonged activity. It primarily stems from changes within muscle fibers. Even before experiencing muscle fatigue, one may feel tired and have the urge to stop the activity. This response, known as central fatigue, occurs due to changes in the central nervous system, namely the brain and spinal cord. While there is no single mechanism that induces fatigue, it may serve as a protective...
4.5K
01:20Titration of a Weak Base with a Strong Acid
9.1K
The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
9.1K
01:25Energy Supply for Muscle Contraction
5.4K
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
5.4K
01:19NMR Spectroscopy Of Amines
10.0K
In proton NMR spectroscopy, primary amines and secondary amines showcase their N–H protons as a broad signal in the chemical shift range between δ 0.5 and 5 ppm. The exact position in this range depends on several factors, including sample concentration, hydrogen bonding, and the type of solvent used. Since amine protons undergo fast proton exchange in solution, the protons are labile and therefore do not participate in any splitting with adjacent protons. Thus, the observed peak is...
10.0K
01:23Urea Cycle
44.2K
The urea cycle describes how liver cells convert ammonia to urea. Ammonia is a toxic waste product of protein catabolism. Land animals must convert ammonia into the less toxic urea which can be safely eliminated by the kidneys through urine. Marine animals excrete ammonia directly, and the surrounding water dilutes the ammonia to safe levels.
44.2K
01:20Overview of Nitrogen Metabolism
8.6K
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
8.6K