An endogenous substance found mainly in skeletal muscle of vertebrates. It has been tried in the treatment of cardiac disorders and has been added to cardioplegic solutions. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1996)
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
An amino acid that occurs in vertebrate tissues and in urine. In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as CREATININE in the urine.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Inorganic salts of phosphoric acid.
Stable phosphorus atoms that have the same atomic number as the element phosphorus, but differ in atomic weight. P-31 is a stable phosphorus isotope.
A transferase that catalyzes formation of PHOSPHOCREATINE from ATP + CREATINE. The reaction stores ATP energy as phosphocreatine. Three cytoplasmic ISOENZYMES have been identified in human tissues: the MM type from SKELETAL MUSCLE, the MB type from myocardial tissue and the BB type from nervous tissue as well as a mitochondrial isoenzyme. Macro-creatine kinase refers to creatine kinase complexed with other serum proteins.
A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
A form of creatine kinase found in the BRAIN.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
An isoenzyme of creatine kinase found in the MUSCLE.
A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
A form of creatine kinase found in the MITOCHONDRIA.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.
A metabolic process that converts GLUCOSE into two molecules of PYRUVIC ACID through a series of enzymatic reactions. Energy generated by this process is conserved in two molecules of ATP. Glycolysis is the universal catabolic pathway for glucose, free glucose, or glucose derived from complex CARBOHYDRATES, such as GLYCOGEN and STARCH.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
Contractile tissue that produces movement in animals.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
This enzyme catalyzes the last step of CREATINE biosynthesis by catalyzing the METHYLATION of guanidinoacetate to CREATINE.
Glycogen is a multibranched polysaccharide of glucose serving as the primary form of energy storage in animals, fungi, and bacteria, stored mainly in liver and muscle tissues. (Two sentences combined as per your request)
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.
A reduction in brain oxygen supply due to ANOXEMIA (a reduced amount of oxygen being carried in the blood by HEMOGLOBIN), or to a restriction of the blood supply to the brain, or both. Severe hypoxia is referred to as anoxia, and is a relatively common cause of injury to the central nervous system. Prolonged brain anoxia may lead to BRAIN DEATH or a PERSISTENT VEGETATIVE STATE. Histologically, this condition is characterized by neuronal loss which is most prominent in the HIPPOCAMPUS; GLOBUS PALLIDUS; CEREBELLUM; and inferior olives.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.
Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.
Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety.
A derivative of ACETIC ACID that contains two CHLORINE atoms attached to its methyl group.
Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.
Inorganic compounds that contain phosphorus as an integral part of the molecule.
Any method of measuring the amount of work done by an organism, usually during PHYSICAL EXERTION. Ergometry also includes measures of power. Some instruments used in these determinations include the hand crank and the bicycle ergometer.
The rate dynamics in chemical or physical systems.
Treatment process involving the injection of fluid into an organ or tissue.
Diet modification and physical exercise to improve the ability to carry out daily tasks and perform physical activities.
A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.
A derivative of ACETIC ACID that contains one IODINE atom attached to its methyl group.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.
An acetic acid ester of CARNITINE that facilitates movement of ACETYL COA into the matrices of mammalian MITOCHONDRIA during the oxidation of FATTY ACIDS.
Contractile activity of the MYOCARDIUM.
A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.
A component of PHOSPHATIDYLCHOLINES or LECITHINS, in which the two hydroxy groups of GLYCEROL are esterified with fatty acids. (From Stedman, 26th ed) It counteracts the effects of urea on enzymes and other macromolecules.
Iodinated derivatives of acetic acid. Iodoacetates are commonly used as alkylating sulfhydryl reagents and enzyme inhibitors in biochemical research.
Muscular contractions characterized by increase in tension without change in length.
2-(2,2-Dicyclohexylethyl)piperidine. Coronary vasodilator used especially for angina of effort. It may cause neuropathy and hepatitis.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The hollow, muscular organ that maintains the circulation of the blood.
A multienzyme complex responsible for the formation of ACETYL COENZYME A from pyruvate. The enzyme components are PYRUVATE DEHYDROGENASE (LIPOAMIDE); dihydrolipoamide acetyltransferase; and LIPOAMIDE DEHYDROGENASE. Pyruvate dehydrogenase complex is subject to three types of control: inhibited by acetyl-CoA and NADH; influenced by the energy state of the cell; and inhibited when a specific serine residue in the pyruvate decarboxylase is phosphorylated by ATP. PYRUVATE DEHYDROGENASE (LIPOAMIDE)-PHOSPHATASE catalyzes reactivation of the complex. (From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed)
Freedom from activity.
Irritants and reagents for labeling terminal amino acid groups.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
An intermediate compound in the metabolism of carbohydrates, proteins, and fats. In thiamine deficiency, its oxidation is retarded and it accumulates in the tissues, especially in nervous structures. (From Stedman, 26th ed)
Elements of limited time intervals, contributing to particular results or situations.
Derivatives of propionic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxyethane structure.
The mitochondria of the myocardium.
The inferior part of the lower extremity between the KNEE and the ANKLE.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
The time span between the beginning of physical activity by an individual and the termination because of exhaustion.
Enzymes of a subclass of TRANSFERASES that catalyze the transfer of an amidino group from donor to acceptor. EC 2.1.4.
Pyruvates, in the context of medical and biochemistry definitions, are molecules that result from the final step of glycolysis, containing a carboxylic acid group and an aldehyde group, playing a crucial role in cellular metabolism, including being converted into Acetyl-CoA to enter the Krebs cycle or lactate under anaerobic conditions.
An enzyme that catalyzes the phosphorylation of AMP to ADP in the presence of ATP or inorganic triphosphate. EC 2.7.4.3.
Relatively complete absence of oxygen in one or more tissues.
Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.
The quadriceps femoris. A collective name of the four-headed skeletal muscle of the thigh, comprised of the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.

Myocardial oxygenation during high work states in hearts with postinfarction remodeling. (1/1198)

BACKGROUND: Postinfarction left ventricular remodeling (LVR) is associated with reductions in myocardial high-energy phosphate (HEP) levels, which are more severe in animals that develop overt congestive heart failure (CHF). During high work states, further HEP loss occurs, which suggests demand-induced ischemia. This study tested the hypothesis that inadequate myocyte oxygen availability is the basis for these HEP abnormalities. METHODS AND RESULTS: Myocardial infarction was produced by left circumflex coronary artery ligation in swine. Studies were performed in 20 normal animals, 14 animals with compensated LVR, and 9 animals with CHF. Phosphocreatine (PCr)/ATP was determined with 31P NMR and deoxymyoglobin (Mb-delta) with 1H NMR in myocardium remote from the infarct. Basal PCr/ATP tended to be decreased in postinfarct hearts, and this was significant in animals with CHF. Infusion of dobutamine (20 microg x kg-1 x min-1 IV) caused doubling of the rate-pressure product in both normal and LVR hearts and resulted in comparable significant decreases of PCr/ATP in both groups. This decrease in PCr/ATP was not associated with detectable Mb-delta. In CHF hearts, rate-pressure product increased only 40% in response to dobutamine; this attenuated response also was not associated with detectable Mb-delta. CONCLUSIONS: Thus, the decrease of PCr/ATP during dobutamine infusion is not the result of insufficient myocardial oxygen availability. Furthermore, in CHF hearts, the low basal PCr/ATP and the attenuated response to dobutamine occurred in the absence of myocardial hypoxia, indicating that the HEP and contractile abnormalities were not the result of insufficient oxygen availability.  (+info)

Preservation of canine myocardial high-energy phosphates during low-flow ischemia with modification of hemoglobin-oxygen affinity. (2/1198)

Conventional approaches for the treatment of myocardial ischemia increase coronary blood flow or reduce myocardial demand. To determine whether a rightward shift in the hemoglobin-oxygen saturation curve would reduce the metabolic and contractile effects of a myocardial oxygen-supply imbalance, we studied the impact of a potent synthetic allosteric modifier of hemoglobin-oxygen affinity, a 2-[4-[[(3,5-disubstituted anilino)carbonyl]methyl] phenoxy] -2-methylproprionic acid derivative (RSR13), during low-flow ischemia. Changes in myocardial high-energy phosphate levels and pH were studied by 31P nuclear magnetic resonance (NMR) spectroscopy in 12 open-chest dogs randomized to receive RSR13 or vehicle control during a reversible reduction of left anterior descending (LAD) coronary artery blood flow. Changes in cardiac metabolites and regional ventricular function studied by pressure segment-length relations were also investigated in additional animals before and after RSR13 administration during low-flow LAD ischemia. The intravenous administration of RSR13 before ischemia resulted in a substantial increase in the mean hemoglobin p50 and attenuated the decline in cardiac creatine phosphate/adenosine triphosphate (PCr/ATP), percent PCr, and pH during ischemia without a change in regional myocardial blood flow, heart rate, or systolic blood pressure. RSR13 given after the onset of low-flow ischemia also improved cardiac PCr/ATP ratios and regional function as measured by fractional shortening and regional work. Thus, synthetic allosteric reduction in hemoglobin-oxygen affinity may be a new and important therapeutic strategy to ameliorate the metabolic and functional consequences of cardiac ischemia.  (+info)

Absolute quantification of brain metabolites by proton magnetic resonance spectroscopy in normal-appearing white matter of multiple sclerosis patients. (3/1198)

The aim of this research was to obtain an absolute quantification of the N-acetyl-aspartate, choline, creatine and phosphocreatine levels in normal-appearing white matter by means of 1H magnetic resonance spectroscopy in a group of multiple sclerosis patients (27 with the relapsing-remitting form and 13 with the secondary progressive form). These values were compared with those of a group of 12 age-matched healthy control subjects. A significant decrease in the N-acetyl-aspartate concentration was found in normal-appearing white matter of frontal and parietal brain areas in multiple sclerosis patients compared with the same areas in control subjects. This reduction was more evident in progressive patients. The decrease in the N-acetyl-aspartate concentration in normal-appearing white matter significantly correlated with the Expanded Disability Status and the lesional load. No significant change was found in the concentration of creatine or choline. This finding concurs with previous evidence of heterogeneity in the multiple sclerosis pathological process which is not confined to the lesions and involves not only myelin, but also axons, even in white matter which appears normal on MRI.  (+info)

Human muscle performance and PCr hydrolysis with varied inspired oxygen fractions: a 31P-MRS study. (4/1198)

The purpose of this study was to use 31P-magnetic resonance spectroscopy to examine the relationships among muscle PCr hydrolysis, intracellular H+ concentration accumulation, and muscle performance during incremental exercise during the inspiration of gas mixtures containing different fractions of inspired O2 (FIO2). We hypothesized that lower FIO2 would result in a greater disruption of intracellular homeostasis at submaximal workloads and thereby initiate an earlier onset of fatigue. Six subjects performed plantar flexion exercise on three separate occasions with the only variable altered for each exercise bout being the FIO2 (either 0.1, 0.21, or 1.00 O2 in balance N2). Work rate was increased (1-W increments starting at 0 W) every 2 min until exhaustion. Time to exhaustion (and thereby workload achieved) was significantly (P < 0.05) greater as FIO2 was increased. Muscle phosphocreatine (PCr) concentration, Pi concentration, and pH at exhaustion were not significantly different among the three FIO2 conditions. However, muscle PCr concentration and pH were significantly reduced at identical submaximal workloads (and thereby equivalent rates of respiration) above 4-5 W during the lowest FIO2 condition compared with the other two FIO2 conditions. These results demonstrate that exhaustion during all FIO2 occurred when a particular intracellular environment was achieved and suggest that during the lowest FIO2 condition, the greater PCr hydrolysis and intracellular acidosis at submaximal workloads may have contributed to the significantly earlier time to exhaustion.  (+info)

Effect of long-term caloric restriction and exercise on muscle bioenergetics and force development in rats. (5/1198)

We evaluated the hypothesis that long-term caloric restriction and exercise would have beneficial effects on muscle bioenergetics and performance in the rat. By themselves, each of these interventions is known to increase longevity, and bioenergetic improvements are thought to be important in this phenomenon. Accordingly, we investigated rats that underwent long-term caloric restriction and were sedentary, ad libitum-fed rats permitted to exercise by daily spontaneous wheel running (AE), and the combination of the dietary and exercise interventions (RE). Ad libitum-fed, sedentary rats comprised the control group. 31P NMR spectra of the gastrocnemius muscle (GM) were collected in vivo at rest and during two periods of electrical stimulation. Neither caloric restriction nor exercise affected the ratio of phosphocreatine to ATP or pH at rest. During the first stimulation and after recovery, the RE group had a significantly smaller decline in pH than did the other groups (P < 0.05). During the second period of stimulation, the decrease in pH was much smaller in all groups than during the first stimulation, with no differences observed among the groups. The combination of caloric restriction and exercise resulted in a significant attenuation in the decline in developed force during the second period of stimulation (P < 0.05). A biochemical correlate of this was a significantly higher concentration of citrate synthase in the GM samples from the RE rats (32.7 +/- 5.4 micromol. min-1. g-1) compared with the AE rats (17.6 +/- 5.7 micromol. min-1. g-1; P < 0.05). Our experiments thus demonstrated a synergistic effect of long-term caloric restriction and free exercise on muscle bioenergetics during electrical stimulation.  (+info)

Relation of impaired energy metabolism to apoptosis and necrosis following transient cerebral hypoxia-ischaemia. (6/1198)

This study investigated whether both mild and severe hypoxia-ischaemia (HI) caused significant numbers of cells to die by apoptosis in the developing brain in vivo. Newborn piglets were subjected to transient global HI and the fraction of all cells in the cingulate gyrus that were apoptotic or necrotic counted 48 h after resuscitation. The mean (S.D.) proportion of apoptotic cells was 11.9% (6.7%) (sham operated controls 4.1% (2.7%)), while 11.4% (8.4%) were necrotic (controls 0.7% (1.3%)) (P<0.05). Apoptotic and necrotic cell counts were both linearly related to the severity of impaired cerebral energy metabolism measured by magnetic resonance spectroscopy (P<0.05), as shown by: (1) the decline in the ratio of nucleotide triphosphates to the exchangeable phosphate pool during HI; (2) the fall in the ratio of phosphocreatine to inorganic phosphate 8 - 48 h after HI; and (3) an increased ratio of lactate to total creatine at both these times. Thus both apoptosis and necrosis occurred in the cingulate gyrus after both severe and mild HI in vivo in proportion to the severity of the insult.  (+info)

Temporal differences in actions of calcium channel blockers on K+ accumulation, cardiac function, and high-energy phosphate levels in ischemic guinea pig hearts. (7/1198)

We investigated temporal differences in the protective action of three types of Ca2+ channel blockers in myocardial ischemia, focusing particularly on the blocking ability under depolarizing conditions. The effects of diltiazem, verapamil, and nifedipine on extracellular potassium concentration ([K+]e), acidosis, and level of metabolic markers were examined during 30-min global ischemia and postischemic left ventricular (LV) function in isolated guinea pig hearts. Diltiazem and verapamil, but not nifedipine, inhibited the late phase (15-30 min) of [K+]e elevation, whereas all three blockers delayed the onset of the early phase (0-8 min) of [K+]e elevation. Diltiazem and verapamil inhibited ischemic contracture and improved postischemic LV function to a greater extent. These differences appeared to be linked to preservation of ATP and creatine phosphate and delay of cessation of anaerobic glycolytic activity. Maneuvers to preserve energy sources during ischemia (decrease in external Ca2+ concentration or pacing at a lower frequency) attenuated the late phase of [K+]e elevation. Inhibition of LV pressure was potentiated 12- and 8.2-fold by diltiazem and verapamil, respectively, at 8.9 mM K+ as compared with 2.9 mM K+, whereas that by nifedipine was unchanged. These results indicate that the differential cardioprotection of Ca2+ channel blockers in the late period of ischemia correlates with preservation of high-energy phosphates as a result of different Ca2+ channel blocking abilities under high [K+]e conditions.  (+info)

An improved capillary electrophoresis method for measuring tissue metabolites associated with cellular energy state. (8/1198)

An improved method for the measurement of tissue metabolites associated with cellular energetic state by capillary electrophoresis is described. This method allows 17 compounds present in a mixture of standards to be determined simultaneously within 43 min with good reproducibility. ATP, ADP, AMP, UTP, IMP, inosine, hypoxanthine, creatine, phosphocreatine, UDP-galactose, NAD and NADH were detected in samples of either rat heart tissue or rat neonatal cardiomyocytes. This method can detect compounds at concentrations of 5 microm in samples. Recoveries for ATP and phosphocreatine added to cardiomyocyte samples were 99.4 +/- 2.1% and 103.1 +/- 3.3%, respectively (mean +/- SEM, n = 3). Our method has been comprehensively validated and is capable of measuring a wider range of tissue metabolites important in assessing cellular energy status than existing methods.  (+info)

Phosphocreatine (PCr) is a high-energy phosphate compound found in the skeletal muscles, cardiac muscle, and brain. It plays a crucial role in energy metabolism and storage within cells. Phosphocreatine serves as an immediate energy reserve that helps regenerate ATP (adenosine triphosphate), the primary source of cellular energy, during short bursts of intense activity or stress. This process is facilitated by the enzyme creatine kinase, which catalyzes the transfer of a phosphate group from phosphocreatine to ADP (adenosine diphosphate) to form ATP.

In a medical context, phosphocreatine levels may be assessed in muscle biopsies or magnetic resonance spectroscopy (MRS) imaging to evaluate muscle energy metabolism and potential mitochondrial dysfunction in conditions such as muscular dystrophies, mitochondrial disorders, and neuromuscular diseases. Additionally, phosphocreatine depletion has been implicated in various pathological processes, including ischemia-reperfusion injury, neurodegenerative disorders, and heart failure.

Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.

During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.

There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.

Creatine is a organic acid that is produced naturally in the liver, kidneys and pancreas. It is also found in small amounts in certain foods such as meat and fish. The chemical formula for creatine is C4H9N3O2. In the body, creatine is converted into creatine phosphate, which is used to help produce energy during high-intensity exercise, such as weightlifting or sprinting.

Creatine can also be taken as a dietary supplement, in the form of creatine monohydrate, with the goal of increasing muscle creatine and phosphocreatine levels, which may improve athletic performance and help with muscle growth. However, it is important to note that while some studies have found that creatine supplementation can improve exercise performance and muscle mass in certain populations, others have not found significant benefits.

Creatine supplements are generally considered safe when used as directed, but they can cause side effects such as weight gain, stomach discomfort, and muscle cramps in some people. It is always recommended to consult a healthcare professional before starting any new supplement regimen.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

Energy metabolism is the process by which living organisms produce and consume energy to maintain life. It involves a series of chemical reactions that convert nutrients from food, such as carbohydrates, fats, and proteins, into energy in the form of adenosine triphosphate (ATP).

The process of energy metabolism can be divided into two main categories: catabolism and anabolism. Catabolism is the breakdown of nutrients to release energy, while anabolism is the synthesis of complex molecules from simpler ones using energy.

There are three main stages of energy metabolism: glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation. Glycolysis occurs in the cytoplasm of the cell and involves the breakdown of glucose into pyruvate, producing a small amount of ATP and nicotinamide adenine dinucleotide (NADH). The citric acid cycle takes place in the mitochondria and involves the further breakdown of pyruvate to produce more ATP, NADH, and carbon dioxide. Oxidative phosphorylation is the final stage of energy metabolism and occurs in the inner mitochondrial membrane. It involves the transfer of electrons from NADH and other electron carriers to oxygen, which generates a proton gradient across the membrane. This gradient drives the synthesis of ATP, producing the majority of the cell's energy.

Overall, energy metabolism is a complex and essential process that allows organisms to grow, reproduce, and maintain their bodily functions. Disruptions in energy metabolism can lead to various diseases, including diabetes, obesity, and neurodegenerative disorders.

Phosphates, in a medical context, refer to the salts or esters of phosphoric acid. Phosphates play crucial roles in various biological processes within the human body. They are essential components of bones and teeth, where they combine with calcium to form hydroxyapatite crystals. Phosphates also participate in energy transfer reactions as phosphate groups attached to adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Additionally, they contribute to buffer systems that help maintain normal pH levels in the body.

Abnormal levels of phosphates in the blood can indicate certain medical conditions. High phosphate levels (hyperphosphatemia) may be associated with kidney dysfunction, hyperparathyroidism, or excessive intake of phosphate-containing products. Low phosphate levels (hypophosphatemia) might result from malnutrition, vitamin D deficiency, or certain diseases affecting the small intestine or kidneys. Both hypophosphatemia and hyperphosphatemia can have significant impacts on various organ systems and may require medical intervention.

Phosphorus isotopes are different forms of the element phosphorus that have different numbers of neutrons in their atomic nuclei, while the number of protons remains the same. The most common and stable isotope of phosphorus is 31P, which contains 15 protons and 16 neutrons. However, there are also several other isotopes of phosphorus that exist, including 32P and 33P, which are radioactive and have 15 protons and 17 or 18 neutrons, respectively. These radioactive isotopes are often used in medical research and treatment, such as in the form of radiopharmaceuticals to diagnose and treat various diseases.

Creatine kinase (CK) is a muscle enzyme that is normally present in small amounts in the blood. It is primarily found in tissues that require a lot of energy, such as the heart, brain, and skeletal muscles. When these tissues are damaged or injured, CK is released into the bloodstream, causing the levels to rise.

Creatine kinase exists in several forms, known as isoenzymes, which can be measured in the blood to help identify the location of tissue damage. The three main isoenzymes are:

1. CK-MM: Found primarily in skeletal muscle
2. CK-MB: Found primarily in heart muscle
3. CK-BB: Found primarily in the brain

Elevated levels of creatine kinase, particularly CK-MB, can indicate damage to the heart muscle, such as occurs with a heart attack. Similarly, elevated levels of CK-BB may suggest brain injury or disease. Overall, measuring creatine kinase levels is a useful diagnostic tool for assessing tissue damage and determining the severity of injuries or illnesses.

Phosphorus is an essential mineral that is required by every cell in the body for normal functioning. It is a key component of several important biomolecules, including adenosine triphosphate (ATP), which is the primary source of energy for cells, and deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which are the genetic materials in cells.

Phosphorus is also a major constituent of bones and teeth, where it combines with calcium to provide strength and structure. In addition, phosphorus plays a critical role in various metabolic processes, including energy production, nerve impulse transmission, and pH regulation.

The medical definition of phosphorus refers to the chemical element with the atomic number 15 and the symbol P. It is a highly reactive non-metal that exists in several forms, including white phosphorus, red phosphorus, and black phosphorus. In the body, phosphorus is primarily found in the form of organic compounds, such as phospholipids, phosphoproteins, and nucleic acids.

Abnormal levels of phosphorus in the body can lead to various health problems. For example, high levels of phosphorus (hyperphosphatemia) can occur in patients with kidney disease or those who consume large amounts of phosphorus-rich foods, and can contribute to the development of calcification of soft tissues and cardiovascular disease. On the other hand, low levels of phosphorus (hypophosphatemia) can occur in patients with malnutrition, vitamin D deficiency, or alcoholism, and can lead to muscle weakness, bone pain, and an increased risk of infection.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

Creatine kinase (CK) is an enzyme found in various tissues in the body, including the heart, brain, and skeletal muscles. It plays a crucial role in energy metabolism by catalyzing the conversion of creatine and adenosine triphosphate (ATP) to phosphocreatine and adenosine diphosphate (ADP). This reaction helps regenerate ATP, which is the primary source of energy for cellular functions.

There are three main isoforms of CK in the human body: CK-MM, CK-MB, and CK-BB. The BB form of creatine kinase (CK-BB) is primarily found in the brain and is present in very low concentrations in other tissues. It is mainly located in the cytosol of neurons and glial cells.

An elevated level of CK-BB in the blood can indicate damage to the central nervous system, particularly in cases of stroke, traumatic brain injury, brain tumors, or neurodegenerative disorders like multiple sclerosis and Alzheimer's disease. However, it is essential to note that CK-BB levels alone are not considered a definitive diagnostic marker for these conditions, as other factors can influence its concentration in the bloodstream. Measurement of CK-BB, along with other biomarkers and clinical assessments, contributes to a more comprehensive understanding of the patient's condition.

Adenosine diphosphate (ADP) is a chemical compound that plays a crucial role in energy transfer within cells. It is a nucleotide, which consists of a adenosine molecule (a sugar molecule called ribose attached to a nitrogenous base called adenine) and two phosphate groups.

In the cell, ADP functions as an intermediate in the conversion of energy from one form to another. When a high-energy phosphate bond in ADP is broken, energy is released and ADP is converted to adenosine triphosphate (ATP), which serves as the main energy currency of the cell. Conversely, when ATP donates a phosphate group to another molecule, it is converted back to ADP, releasing energy for the cell to use.

ADP also plays a role in blood clotting and other physiological processes. In the coagulation cascade, ADP released from damaged red blood cells can help activate platelets and initiate the formation of a blood clot.

Lactates, also known as lactic acid, are compounds that are produced by muscles during intense exercise or other conditions of low oxygen supply. They are formed from the breakdown of glucose in the absence of adequate oxygen to complete the full process of cellular respiration. This results in the production of lactate and a hydrogen ion, which can lead to a decrease in pH and muscle fatigue.

In a medical context, lactates may be measured in the blood as an indicator of tissue oxygenation and metabolic status. Elevated levels of lactate in the blood, known as lactic acidosis, can indicate poor tissue perfusion or hypoxia, and may be seen in conditions such as sepsis, cardiac arrest, and severe shock. It is important to note that lactates are not the primary cause of acidemia (low pH) in lactic acidosis, but rather a marker of the underlying process.

Creatine kinase (CK) is an enzyme found in various tissues in the body, including the heart, brain, and skeletal muscles. It plays a crucial role in energy metabolism by catalyzing the conversion of creatine and adenosine triphosphate (ATP) to phosphocreatine and adenosine diphosphate (ADP). This reaction helps regenerate ATP, which is the primary source of energy for cellular functions.

There are three main isoforms of CK in the human body: CK-MM, CK-MB, and CK-BB. The CK-MM form is primarily found in skeletal muscles and constitutes approximately 95% to 99% of the total CK activity in healthy individuals. It is a dimer composed of two muscle-specific subunits (M-CK).

Elevated levels of CK-MM in the blood can indicate damage or injury to skeletal muscles. This can occur due to various reasons, such as muscle trauma, strenuous exercise, muscle diseases, and certain medications. Measuring CK-MM levels is essential in diagnosing and monitoring conditions associated with muscle damage or disease.

Lactic acid, also known as 2-hydroxypropanoic acid, is a chemical compound that plays a significant role in various biological processes. In the context of medicine and biochemistry, lactic acid is primarily discussed in relation to muscle metabolism and cellular energy production. Here's a medical definition for lactic acid:

Lactic acid (LA): A carboxylic acid with the molecular formula C3H6O3 that plays a crucial role in anaerobic respiration, particularly during strenuous exercise or conditions of reduced oxygen availability. It is formed through the conversion of pyruvate, catalyzed by the enzyme lactate dehydrogenase (LDH), when there is insufficient oxygen to complete the final step of cellular respiration in the Krebs cycle. The accumulation of lactic acid can lead to acidosis and muscle fatigue. Additionally, lactic acid serves as a vital intermediary in various metabolic pathways and is involved in the production of glucose through gluconeogenesis in the liver.

Oxygen consumption, also known as oxygen uptake, is the amount of oxygen that is consumed or utilized by the body during a specific period of time, usually measured in liters per minute (L/min). It is a common measurement used in exercise physiology and critical care medicine to assess an individual's aerobic metabolism and overall health status.

In clinical settings, oxygen consumption is often measured during cardiopulmonary exercise testing (CPET) to evaluate cardiovascular function, pulmonary function, and exercise capacity in patients with various medical conditions such as heart failure, chronic obstructive pulmonary disease (COPD), and other respiratory or cardiac disorders.

During exercise, oxygen is consumed by the muscles to generate energy through a process called oxidative phosphorylation. The amount of oxygen consumed during exercise can provide important information about an individual's fitness level, exercise capacity, and overall health status. Additionally, measuring oxygen consumption can help healthcare providers assess the effectiveness of treatments and rehabilitation programs in patients with various medical conditions.

Creatine kinase (CK), also known as creatine phosphokinase (CPK), is an enzyme found in various tissues in the body, including the heart, brain, and skeletal muscles. It plays a crucial role in energy metabolism by catalyzing the conversion of creatine and adenosine triphosphate (ATP) to phosphocreatine and adenosine diphosphate (ADP). This reaction helps regenerate ATP, which is the primary source of energy for cellular functions.

There are three main forms of CK found in the body: CK-MM (muscle form), CK-BB (brain form), and CK-MB (mixture of muscle and brain forms). Additionally, there is a mitochondrial form of creatine kinase called CKmt or CK-MT, which is primarily located within the mitochondria.

Mitochondrial creatine kinase (CKmt) has two main isoforms: ubiquitous CKmt1 and sarcomeric CKmt2. These isoforms are responsible for catalyzing the transfer of high-energy phosphates between ATP and phosphocreatine within the mitochondria, which helps maintain energy homeostasis in the cell.

Abnormal levels of creatine kinase, including the mitochondrial form, can indicate tissue damage or disease. For example, increased CKmt levels may be associated with mitochondrial disorders, neurodegenerative diseases, or muscle-wasting conditions. However, measuring CKmt specifically is not as common in clinical practice as measuring other CK isoforms, and its interpretation requires specialized knowledge and context.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Oxidative phosphorylation is the metabolic process by which cells use enzymes to generate energy in the form of adenosine triphosphate (ATP) from the oxidation of nutrients, such as glucose or fatty acids. This process occurs in the inner mitochondrial membrane of eukaryotic cells and is facilitated by the electron transport chain, which consists of a series of protein complexes that transfer electrons from donor molecules to acceptor molecules. As the electrons are passed along the chain, they release energy that is used to pump protons across the membrane, creating a gradient. The ATP synthase enzyme then uses the flow of protons back across the membrane to generate ATP, which serves as the main energy currency for cellular processes.

Glycolysis is a fundamental metabolic pathway that occurs in the cytoplasm of cells, consisting of a series of biochemical reactions. It's the process by which a six-carbon glucose molecule is broken down into two three-carbon pyruvate molecules. This process generates a net gain of two ATP molecules (the main energy currency in cells), two NADH molecules, and two water molecules.

Glycolysis can be divided into two stages: the preparatory phase (or 'energy investment' phase) and the payoff phase (or 'energy generation' phase). During the preparatory phase, glucose is phosphorylated twice to form glucose-6-phosphate and then converted to fructose-1,6-bisphosphate. These reactions consume two ATP molecules but set up the subsequent breakdown of fructose-1,6-bisphosphate into triose phosphates in the payoff phase. In this second stage, each triose phosphate is further oxidized and degraded to produce one pyruvate molecule, one NADH molecule, and one ATP molecule through substrate-level phosphorylation.

Glycolysis does not require oxygen to proceed; thus, it can occur under both aerobic (with oxygen) and anaerobic (without oxygen) conditions. In the absence of oxygen, the pyruvate produced during glycolysis is further metabolized through fermentation pathways such as lactic acid fermentation or alcohol fermentation to regenerate NAD+, which is necessary for glycolysis to continue.

In summary, glycolysis is a crucial process in cellular energy metabolism, allowing cells to convert glucose into ATP and other essential molecules while also serving as a starting point for various other biochemical pathways.

Mitochondria in muscle, also known as the "powerhouses" of the cell, are organelles that play a crucial role in generating energy for muscle cells through a process called cellular respiration. They convert the chemical energy found in glucose and oxygen into ATP (adenosine triphosphate), which is the main source of energy used by cells.

Muscle cells contain a high number of mitochondria due to their high energy demands for muscle contraction and relaxation. The number and size of mitochondria in muscle fibers can vary depending on the type of muscle fiber, with slow-twitch, aerobic fibers having more numerous and larger mitochondria than fast-twitch, anaerobic fibers.

Mitochondrial dysfunction has been linked to various muscle disorders, including mitochondrial myopathies, which are characterized by muscle weakness, exercise intolerance, and other symptoms related to impaired energy production in the muscle cells.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

Exercise is defined in the medical context as a physical activity that is planned, structured, and repetitive, with the primary aim of improving or maintaining one or more components of physical fitness. Components of physical fitness include cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, and body composition. Exercise can be classified based on its intensity (light, moderate, or vigorous), duration (length of time), and frequency (number of times per week). Common types of exercise include aerobic exercises, such as walking, jogging, cycling, and swimming; resistance exercises, such as weightlifting; flexibility exercises, such as stretching; and balance exercises. Exercise has numerous health benefits, including reducing the risk of chronic diseases, improving mental health, and enhancing overall quality of life.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

Guanidinoacetate N-Methyltransferase (GAMT) is an enzyme that plays a crucial role in the biosynthesis of creatine, a nitrogenous organic acid that occurs naturally in vertebrates and helps to supply energy to all cells in the body, primarily muscle.

The GAMT enzyme catalyzes the reaction of guanidinoacetate and a methyl group donor (S-adenosylmethionine) to produce creatine, as well as S-adenosylhomocysteine. A deficiency in this enzyme leads to a rare genetic disorder called Guanidinoacetate Methyltransferase Deficiency (GAMT deficiency), which is characterized by an accumulation of guanidinoacetate in the body and low levels of creatine, resulting in neurological symptoms such as developmental delay, seizures, and movement disorders.

Glycogen is a complex carbohydrate that serves as the primary form of energy storage in animals, fungi, and bacteria. It is a polysaccharide consisting of long, branched chains of glucose molecules linked together by glycosidic bonds. Glycogen is stored primarily in the liver and muscles, where it can be quickly broken down to release glucose into the bloodstream during periods of fasting or increased metabolic demand.

In the liver, glycogen plays a crucial role in maintaining blood glucose levels by releasing glucose when needed, such as between meals or during exercise. In muscles, glycogen serves as an immediate energy source for muscle contractions during intense physical activity. The ability to store and mobilize glycogen is essential for the proper functioning of various physiological processes, including athletic performance, glucose homeostasis, and overall metabolic health.

Adenine nucleotides are molecules that consist of a nitrogenous base called adenine, which is linked to a sugar molecule (ribose in the case of adenosine monophosphate or AMP, and deoxyribose in the case of adenosine diphosphate or ADP and adenosine triphosphate or ATP) and one, two, or three phosphate groups. These molecules play a crucial role in energy transfer and metabolism within cells.

AMP contains one phosphate group, while ADP contains two phosphate groups, and ATP contains three phosphate groups. When a phosphate group is removed from ATP, energy is released, which can be used to power various cellular processes such as muscle contraction, nerve impulse transmission, and protein synthesis. The reverse reaction, in which a phosphate group is added back to ADP or AMP to form ATP, requires energy input and often involves the breakdown of nutrients such as glucose or fatty acids.

In addition to their role in energy metabolism, adenine nucleotides also serve as precursors for other important molecules, including DNA and RNA, coenzymes, and signaling molecules.

Aspartic acid is an α-amino acid with the chemical formula HO2CCH(NH2)CO2H. It is one of the twenty standard amino acids, and it is a polar, negatively charged, and hydrophilic amino acid. In proteins, aspartic acid usually occurs in its ionized form, aspartate, which has a single negative charge.

Aspartic acid plays important roles in various biological processes, including metabolism, neurotransmitter synthesis, and energy production. It is also a key component of many enzymes and proteins, where it often contributes to the formation of ionic bonds and helps stabilize protein structure.

In addition to its role as a building block of proteins, aspartic acid is also used in the synthesis of other important biological molecules, such as nucleotides, which are the building blocks of DNA and RNA. It is also a component of the dipeptide aspartame, an artificial sweetener that is widely used in food and beverages.

Like other amino acids, aspartic acid is essential for human health, but it cannot be synthesized by the body and must be obtained through the diet. Foods that are rich in aspartic acid include meat, poultry, fish, dairy products, eggs, legumes, and some fruits and vegetables.

Brain hypoxia is a medical condition characterized by a reduced supply of oxygen to the brain. The brain requires a continuous supply of oxygen to function properly, and even a brief period of hypoxia can cause significant damage to brain cells.

Hypoxia can result from various conditions, such as cardiac arrest, respiratory failure, carbon monoxide poisoning, or high altitude exposure. When the brain is deprived of oxygen, it can lead to a range of symptoms, including confusion, disorientation, seizures, loss of consciousness, and ultimately, brain death.

Brain hypoxia is a medical emergency that requires immediate treatment to prevent long-term neurological damage or death. Treatment typically involves addressing the underlying cause of hypoxia, such as administering oxygen therapy, resuscitating the heart, or treating respiratory failure. In some cases, more invasive treatments, such as therapeutic hypothermia or mechanical ventilation, may be necessary to prevent further brain damage.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Muscle fatigue is a condition characterized by a reduction in the ability of a muscle to generate force or power, typically after prolonged or strenuous exercise. It is often accompanied by sensations of tiredness, weakness, and discomfort in the affected muscle(s). The underlying mechanisms of muscle fatigue are complex and involve both peripheral factors (such as changes in muscle metabolism, ion handling, and neuromuscular transmission) and central factors (such as changes in the nervous system's ability to activate muscles). Muscle fatigue can also occur as a result of various medical conditions or medications that impair muscle function.

Adenosine monophosphate (AMP) is a nucleotide that is the monophosphate ester of adenosine, consisting of the nitrogenous base adenine attached to the 1' carbon atom of ribose via a β-N9-glycosidic bond, which in turn is esterified to a phosphate group. It is an important molecule in biological systems as it plays a key role in cellular energy transfer and storage, serving as a precursor to other nucleotides such as ADP and ATP. AMP is also involved in various signaling pathways and can act as a neurotransmitter in the central nervous system.

Inosine monophosphate (IMP) is a nucleotide that plays a crucial role in the metabolic pathways of energy production and purine synthesis in cells. It is an ester of the nucleoside inosine and phosphoric acid. IMP is an important intermediate in the conversion of adenosine monophosphate (AMP) to guanosine monophosphate (GMP) in the purine nucleotide cycle, which is critical for maintaining the balance of purine nucleotides in the body. Additionally, IMP can be converted back to AMP through the action of the enzyme adenylosuccinate lyase. IMP has been studied for its potential therapeutic benefits in various medical conditions, including neurodegenerative disorders and ischemia-reperfusion injury.

Dichloroacetic acid (DCA) is a chemical compound with the formula CCl2CO2H. It is a colorless liquid that is used as a reagent in organic synthesis and as a laboratory research tool. DCA is also a byproduct of water chlorination and has been found to occur in low levels in some chlorinated drinking waters.

In the medical field, DCA has been studied for its potential anticancer effects. Preclinical studies have suggested that DCA may be able to selectively kill cancer cells by inhibiting the activity of certain enzymes involved in cell metabolism. However, more research is needed to determine whether DCA is safe and effective as a cancer treatment in humans.

It is important to note that DCA is not currently approved by regulatory agencies such as the U.S. Food and Drug Administration (FDA) for use as a cancer treatment. It should only be used in clinical trials or under the supervision of a qualified healthcare professional.

Physical exertion is defined as the act of applying energy to physically demandable activities or tasks, which results in various body systems working together to produce movement and maintain homeostasis. It often leads to an increase in heart rate, respiratory rate, and body temperature, among other physiological responses. The level of physical exertion can vary based on the intensity, duration, and frequency of the activity.

It's important to note that engaging in regular physical exertion has numerous health benefits, such as improving cardiovascular fitness, strengthening muscles and bones, reducing stress, and preventing chronic diseases like obesity, diabetes, and heart disease. However, it is also crucial to balance physical exertion with adequate rest and recovery time to avoid overtraining or injury.

Phosphorus compounds refer to chemical substances that contain phosphorus (P) combined with one or more other elements. Phosphorus can form a variety of compounds due to its ability to exist in several oxidation states, most commonly +3 and +5.

In biological systems, phosphorus is an essential element for life, playing crucial roles in energy transfer, metabolism, and structural components of cells. Some common examples of phosphorus compounds include:

1. Phosphoric acid (H3PO4): A weak triprotic acid that forms salts called phosphates when combined with metal ions or basic radicals.
2. Phosphates (PO4^3-): The salt or ester form of phosphoric acid, widely found in nature and essential for various biological processes such as bone formation, energy metabolism, and nucleic acid synthesis.
3. Phosphorus pentachloride (PCl5): A pungent, white crystalline solid used in organic chemistry as a chlorinating agent.
4. Phosphorus trichloride (PCl3): A colorless liquid with a suffocating odor, used in the production of various chemical compounds, including pharmaceuticals and agrochemicals.
5. Dicalcium phosphate (CaHPO4): A calcium salt of phosphoric acid, commonly found in mineral supplements and used as a dietary supplement for animals and humans.
6. Adenosine triphosphate (ATP): A high-energy molecule that stores and transfers energy within cells, playing a critical role in metabolic processes such as muscle contraction and biosynthesis.

Phosphorus compounds have numerous applications across various industries, including agriculture, food processing, pharmaceuticals, and chemical manufacturing.

Ergometry is a medical term that refers to the process of measuring the amount of work or energy expended by an individual during physical exercise. It is often used in clinical settings to assess cardiopulmonary function, functional capacity, and exercise tolerance in patients with various medical conditions such as heart disease, lung disease, and metabolic disorders.

Ergometry typically involves the use of specialized equipment, such as a treadmill or stationary bike, which is connected to a computer that measures and records various physiological parameters such as heart rate, blood pressure, oxygen consumption, and carbon dioxide production during exercise. The data collected during an ergometry test can help healthcare providers diagnose medical conditions, develop treatment plans, and monitor the effectiveness of interventions over time.

There are several types of ergometry tests, including:

1. Cardiopulmonary Exercise Testing (CPET): This is a comprehensive assessment that measures an individual's cardiovascular, respiratory, and metabolic responses to exercise. It typically involves the use of a treadmill or stationary bike and provides detailed information about an individual's functional capacity, exercise tolerance, and overall health status.
2. Stress Echocardiography: This is a type of ergometry test that uses ultrasound imaging to assess heart function during exercise. It involves the use of a treadmill or stationary bike and provides information about blood flow to the heart, wall motion abnormalities, and valve function.
3. Nuclear Stress Test: This is a type of ergometry test that uses radioactive tracers to assess heart function during exercise. It involves the use of a treadmill or stationary bike and provides information about blood flow to the heart, myocardial perfusion, and viability.
4. Six-Minute Walk Test: This is a simple ergometry test that measures an individual's distance walked in six minutes. It is often used to assess functional capacity and exercise tolerance in patients with chronic lung disease or heart failure.

Overall, ergometry is an important tool in the diagnosis and management of various medical conditions and can provide valuable information about an individual's health status and response to treatment.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Perfusion, in medical terms, refers to the process of circulating blood through the body's organs and tissues to deliver oxygen and nutrients and remove waste products. It is a measure of the delivery of adequate blood flow to specific areas or tissues in the body. Perfusion can be assessed using various methods, including imaging techniques like computed tomography (CT) scans, magnetic resonance imaging (MRI), and perfusion scintigraphy.

Perfusion is critical for maintaining proper organ function and overall health. When perfusion is impaired or inadequate, it can lead to tissue hypoxia, acidosis, and cell death, which can result in organ dysfunction or failure. Conditions that can affect perfusion include cardiovascular disease, shock, trauma, and certain surgical procedures.

Physical conditioning in the context of human health refers to the process of improving physical fitness and overall health through regular exercise and physical activity. This involves engaging in various forms of exercise such as cardio, strength training, flexibility exercises, and balance exercises to enhance various components of physical fitness including:

1. Cardiovascular endurance: The ability of the heart and lungs to supply oxygen to the muscles during sustained physical activity.
2. Muscular strength: The amount of force a muscle can exert in a single effort.
3. Muscular endurance: The ability of a muscle or muscle group to sustain repeated contractions over time.
4. Flexibility: The range of motion around a joint.
5. Body composition: The proportion of lean body mass (muscle, bone, and organs) to fat mass in the body.

Physical conditioning aims to improve these components of fitness, leading to overall improvements in health, functional capacity, and reduced risk of chronic diseases such as obesity, diabetes, heart disease, and cancer. It is an essential component of a healthy lifestyle and is recommended for people of all ages and abilities.

Choline is an essential nutrient that is vital for the normal functioning of all cells, particularly those in the brain and liver. It is a water-soluble compound that is neither a vitamin nor a mineral, but is often grouped with vitamins because it has many similar functions. Choline is a precursor to the neurotransmitter acetylcholine, which plays an important role in memory, mood, and other cognitive processes. It also helps to maintain the structural integrity of cell membranes and is involved in the transport and metabolism of fats.

Choline can be synthesized by the body in small amounts, but it is also found in a variety of foods such as eggs, meat, fish, nuts, and cruciferous vegetables. Some people may require additional choline through supplementation, particularly if they follow a vegetarian or vegan diet, are pregnant or breastfeeding, or have certain medical conditions that affect choline metabolism.

Deficiency in choline can lead to a variety of health problems, including liver disease, muscle damage, and neurological disorders. On the other hand, excessive intake of choline can cause fishy body odor, sweating, and gastrointestinal symptoms such as diarrhea and vomiting. It is important to maintain adequate levels of choline through a balanced diet and, if necessary, supplementation under the guidance of a healthcare professional.

Iodoacetic acid is not typically defined in the context of medical terminology, but rather it is a chemical compound with the formula CH2ICO2H. It is a colorless, oily liquid that is used in organic synthesis as an alkylating agent and also has been studied for its potential antibacterial and antifungal properties.

In medical contexts, iodoacetic acid may be mentioned in relation to its use in research or in the discussion of certain chemical reactions that may occur in the body. For example, it can inhibit the enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which plays a crucial role in energy metabolism. However, iodoacetic acid itself is not a medical treatment or therapy.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Brain chemistry refers to the chemical processes that occur within the brain, particularly those involving neurotransmitters, neuromodulators, and neuropeptides. These chemicals are responsible for transmitting signals between neurons (nerve cells) in the brain, allowing for various cognitive, emotional, and physical functions.

Neurotransmitters are chemical messengers that transmit signals across the synapse (the tiny gap between two neurons). Examples of neurotransmitters include dopamine, serotonin, norepinephrine, GABA (gamma-aminobutyric acid), and glutamate. Each neurotransmitter has a specific role in brain function, such as regulating mood, motivation, attention, memory, and movement.

Neuromodulators are chemicals that modify the effects of neurotransmitters on neurons. They can enhance or inhibit the transmission of signals between neurons, thereby modulating brain activity. Examples of neuromodulators include acetylcholine, histamine, and substance P.

Neuropeptides are small protein-like molecules that act as neurotransmitters or neuromodulators. They play a role in various physiological functions, such as pain perception, stress response, and reward processing. Examples of neuropeptides include endorphins, enkephalins, and oxytocin.

Abnormalities in brain chemistry can lead to various neurological and psychiatric conditions, such as depression, anxiety disorders, schizophrenia, Parkinson's disease, and Alzheimer's disease. Understanding brain chemistry is crucial for developing effective treatments for these conditions.

Acetyl-L-carnitine, also known as ALCAR, is a form of the amino acid carnitine. It is a naturally occurring substance in the body that plays a crucial role in energy production in cells, particularly within mitochondria, the "powerhouses" of the cell.

Acetyl-L-carnitine is involved in the transport of fatty acids into the mitochondria, where they can be broken down to produce energy. It also functions as an antioxidant, helping to protect cells from damage caused by free radicals.

This compound has been studied for its potential benefits in various medical conditions, including neurological disorders, cardiovascular diseases, and liver diseases. Some research suggests that Acetyl-L-carnitine may help improve cognitive function, reduce fatigue, and alleviate pain. However, more studies are needed to confirm these findings and establish the optimal dosage and safety profiles for different medical conditions.

It is important to note that while Acetyl-L-carnitine is available as a dietary supplement, its use should be discussed with a healthcare provider before starting any new supplement regimen, especially if you have a medical condition or are taking medication.

Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.

During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.

Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.

Acidosis is a medical condition that occurs when there is an excess accumulation of acid in the body or when the body loses its ability to effectively regulate the pH level of the blood. The normal pH range of the blood is slightly alkaline, between 7.35 and 7.45. When the pH falls below 7.35, it is called acidosis.

Acidosis can be caused by various factors, including impaired kidney function, respiratory problems, diabetes, severe dehydration, alcoholism, and certain medications or toxins. There are two main types of acidosis: metabolic acidosis and respiratory acidosis.

Metabolic acidosis occurs when the body produces too much acid or is unable to eliminate it effectively. This can be caused by conditions such as diabetic ketoacidosis, lactic acidosis, kidney failure, and ingestion of certain toxins.

Respiratory acidosis, on the other hand, occurs when the lungs are unable to remove enough carbon dioxide from the body, leading to an accumulation of acid. This can be caused by conditions such as chronic obstructive pulmonary disease (COPD), asthma, and sedative overdose.

Symptoms of acidosis may include fatigue, shortness of breath, confusion, headache, rapid heartbeat, and in severe cases, coma or even death. Treatment for acidosis depends on the underlying cause and may include medications, oxygen therapy, fluid replacement, and dialysis.

Glycerylphosphorylcholine (GPC) is not typically considered a medical term, but it is a choline-containing phospholipid that can be found in various tissues and fluids within the human body. It is also available as a dietary supplement. Here's a definition of Glycerylphosphorylcholine:

Glycerylphosphorylcholine (GPC) is a natural choline-containing compound that is present in various tissues and fluids within the human body, including neural tissue, muscle, and blood. It plays an essential role in the synthesis of the neurotransmitter acetylcholine, which is involved in memory, learning, and other cognitive functions. GPC can also be found in some foods, such as egg yolks and soybeans, and is available as a dietary supplement. In the body, GPC can be converted to phosphatidylcholine, another important phospholipid that is necessary for maintaining cell membrane structure and function.

Iodoacetates are salts or esters of iodoacetic acid, an organic compound containing iodine. In medicine, iodoacetates have been used as topical antiseptics and anti-inflammatory agents. However, their use is limited due to potential skin irritation and the availability of safer alternatives.

In a broader context, iodoacetates are also known for their chemical properties. They can act as alkylating agents, which means they can react with proteins and enzymes in living organisms, disrupting their function. This property has been exploited in research to study various cellular processes.

Isometric contraction is a type of muscle activation where the muscle contracts without any change in the length of the muscle or movement at the joint. This occurs when the force generated by the muscle matches the external force opposing it, resulting in a balanced state with no visible movement. It is commonly experienced during activities such as holding a heavy object in static position or trying to push against an immovable object. Isometric contractions are important in maintaining posture and providing stability to joints.

Perhexiline is a prescription medication that belongs to a class of drugs called anti-anginal agents. It works by increasing the supply of oxygen to the heart muscle and decreasing its demand for oxygen, which helps prevent angina (chest pain) caused by coronary artery disease.

The medical definition of Perhexiline is:

Perhexiline is a cardiac anti-anginal agent with a mechanism of action that involves inhibition of the mitochondrial enzyme carnitine palmitoyltransferase, which results in increased myocardial oxygen delivery and decreased myocardial oxygen demand. It is used in the management of chronic stable angina pectoris that is refractory to other anti-anginal therapies. Perhexiline has a narrow therapeutic index and requires careful monitoring of plasma concentrations to avoid toxicity, which can manifest as neurological, hepatic, or cardiac adverse effects.

Glucose is a simple monosaccharide (or single sugar) that serves as the primary source of energy for living organisms. It's a fundamental molecule in biology, often referred to as "dextrose" or "grape sugar." Glucose has the molecular formula C6H12O6 and is vital to the functioning of cells, especially those in the brain and nervous system.

In the body, glucose is derived from the digestion of carbohydrates in food, and it's transported around the body via the bloodstream to cells where it can be used for energy. Cells convert glucose into a usable form through a process called cellular respiration, which involves a series of metabolic reactions that generate adenosine triphosphate (ATP)—the main currency of energy in cells.

Glucose is also stored in the liver and muscles as glycogen, a polysaccharide (multiple sugar) that can be broken down back into glucose when needed for energy between meals or during physical activity. Maintaining appropriate blood glucose levels is crucial for overall health, and imbalances can lead to conditions such as diabetes mellitus.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

The Pyruvate Dehydrogenase Complex (PDC) is a multi-enzyme complex that plays a crucial role in cellular energy metabolism. It is located in the mitochondrial matrix and catalyzes the oxidative decarboxylation of pyruvate, the end product of glycolysis, into acetyl-CoA. This reaction links the carbohydrate metabolism (glycolysis) to the citric acid cycle (Krebs cycle), enabling the continuation of energy production in the form of ATP through oxidative phosphorylation.

The Pyruvate Dehydrogenase Complex consists of three main enzymes: pyruvate dehydrogenase (E1), dihydrolipoyl transacetylase (E2), and dihydrolipoyl dehydrogenase (E3). Additionally, two regulatory enzymes are associated with the complex: pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP). These regulatory enzymes control the activity of the PDC through reversible phosphorylation and dephosphorylation, allowing the cell to adapt to varying energy demands and substrate availability.

Deficiencies or dysfunctions in the Pyruvate Dehydrogenase Complex can lead to various metabolic disorders, such as pyruvate dehydrogenase deficiency, which may result in neurological impairments and lactic acidosis due to disrupted energy metabolism.

Medical Definition of Rest:

1. A state of motionless, inactivity, or repose of the body.
2. A period during which such a state is experienced, usually as a result of sleep or relaxation.
3. The cessation of mental or physical activity; a pause or interval of rest is a period of time in which one does not engage in work or exertion.
4. In medical contexts, rest may also refer to the treatment or management strategy that involves limiting physical activity or exertion in order to allow an injury or illness to heal, reduce pain or prevent further harm. This can include bed rest, where a person is advised to stay in bed for a certain period of time.
5. In physiology, rest refers to the state of the body when it is not engaged in physical activity and the muscles are at their resting length and tension. During rest, the body's systems have an opportunity to recover from the demands placed on them during activity, allowing for optimal functioning and overall health.

Dinitrofluorobenzene (DNFB) is a chemical compound that is often used in laboratory settings for research purposes. It is an aromatic organic compound that contains two nitro groups and a fluorine atom attached to a benzene ring. Dinitrofluorobenzene is primarily known for its ability to act as a hapten, which means it can bind to proteins in the body and stimulate an immune response.

In medical research, DNFB has been used as a contact sensitizer to study the mechanisms of allergic contact dermatitis, a type of skin reaction that occurs when the immune system becomes sensitized to a particular substance and then reacts to it upon subsequent exposure. When applied to the skin, DNFB can cause a red, itchy, and painful rash in individuals who have been previously sensitized to the compound. By studying this reaction, researchers can gain insights into the immune responses that underlie allergic reactions more broadly.

It is important to note that dinitrofluorobenzene is not used as a therapeutic agent in clinical medicine and should only be handled by trained professionals in a controlled laboratory setting due to its potential hazards, including skin and eye irritation, respiratory problems, and potential long-term health effects.

In the context of medicine, particularly in relation to cancer treatment, protons refer to positively charged subatomic particles found in the nucleus of an atom. Proton therapy, a type of radiation therapy, uses a beam of protons to target and destroy cancer cells with high precision, minimizing damage to surrounding healthy tissue. The concentrated dose of radiation is delivered directly to the tumor site, reducing side effects and improving quality of life during treatment.

Pyruvic acid, also known as 2-oxopropanoic acid, is a key metabolic intermediate in both anaerobic and aerobic respiration. It is a carboxylic acid with a ketone functional group, making it a β-ketoacid. In the cytosol, pyruvate is produced from glucose during glycolysis, where it serves as a crucial link between the anaerobic breakdown of glucose and the aerobic process of cellular respiration in the mitochondria.

During low oxygen availability or high energy demands, pyruvate can be converted into lactate through anaerobic glycolysis, allowing for the continued production of ATP (adenosine triphosphate) without oxygen. In the presence of adequate oxygen and functional mitochondria, pyruvate is transported into the mitochondrial matrix where it undergoes oxidative decarboxylation to form acetyl-CoA by the enzyme pyruvate dehydrogenase complex (PDC). This reaction also involves the reduction of NAD+ to NADH and the release of CO2. Acetyl-CoA then enters the citric acid cycle, where it is further oxidized to produce energy in the form of ATP, NADH, FADH2, and GTP (guanosine triphosphate) through a series of enzymatic reactions.

In summary, pyruvic acid is a vital metabolic intermediate that plays a significant role in energy production pathways, connecting glycolysis to both anaerobic and aerobic respiration.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Propionates, in a medical context, most commonly refer to a group of medications that are used as topical creams or gels to treat fungal infections of the skin. Propionic acid and its salts, such as propionate, are the active ingredients in these medications. They work by inhibiting the growth of fungi, which causes the infection. Common examples of propionate-containing medications include creams used to treat athlete's foot, ringworm, and jock itch.

It is important to note that there are many different types of medications and compounds that contain the word "propionate" in their name, as it refers to a specific chemical structure. However, in a medical context, it most commonly refers to antifungal creams or gels.

I'm happy to help! However, it seems like there are two terms combined into one request: "Mitochondria" and "Heart." I will provide separate definitions for each.

Mitochondrion (singular) or Mitochondria (plural): These are specialized structures found in the cytoplasm of most eukaryotic cells (cells with a true nucleus), including human cells. They are often referred to as the "powerhouse" of the cell because they generate energy in the form of ATP (adenosine triphosphate) through a process called oxidative phosphorylation. Mitochondria contain their own DNA, which is distinct from the nuclear DNA, and are believed to have originated from ancient bacteria that established a symbiotic relationship with primitive eukaryotic cells.

Heart: In human anatomy, the heart is a muscular organ responsible for pumping blood throughout the body. It is located in the thoracic cavity, slightly left of the center, and is enclosed by the pericardium, a double-walled sac that provides protection and lubrication for the heart's movement. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it to the rest of the body. The heart's pumping action is regulated by electrical signals that originate in a group of specialized cardiac muscle cells called the sinoatrial node (SA node).

In medical terms, the leg refers to the lower portion of the human body that extends from the knee down to the foot. It includes the thigh (femur), lower leg (tibia and fibula), foot, and ankle. The leg is primarily responsible for supporting the body's weight and enabling movements such as standing, walking, running, and jumping.

The leg contains several important structures, including bones, muscles, tendons, ligaments, blood vessels, nerves, and joints. These structures work together to provide stability, support, and mobility to the lower extremity. Common medical conditions that can affect the leg include fractures, sprains, strains, infections, peripheral artery disease, and neurological disorders.

Medical Definition:

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.

Physical endurance is the ability of an individual to withstand and resist physical fatigue over prolonged periods of strenuous activity, exercise, or exertion. It involves the efficient functioning of various body systems, including the cardiovascular system (heart, blood vessels, and blood), respiratory system (lungs and airways), and musculoskeletal system (muscles, bones, tendons, ligaments, and cartilage).

Physical endurance is often measured in terms of aerobic capacity or stamina, which refers to the body's ability to supply oxygen to muscles during sustained physical activity. It can be improved through regular exercise, such as running, swimming, cycling, or weightlifting, that challenges the body's major muscle groups and raises the heart rate for extended periods.

Factors that influence physical endurance include genetics, age, sex, fitness level, nutrition, hydration, sleep quality, stress management, and overall health status. It is essential to maintain good physical endurance to perform daily activities efficiently, reduce the risk of chronic diseases, and enhance overall well-being.

Amidinotransferases are a group of enzymes that play a role in the metabolism of amino acids and other biologically active compounds. These enzymes catalyze the transfer of an amidino group (-NH-C=NH) from one molecule to another, typically from an amino acid or related compound donor to an acceptor molecule.

The amidinotransferases are classified as a subgroup of the larger family of enzymes known as transferases, which catalyze the transfer of various functional groups between molecules. Within this family, the amidinotransferases are further divided into several subfamilies based on their specific functions and the types of donor and acceptor molecules they act upon.

One example of an amidinotransferase is arginine:glycine amidinotransferase (AGAT), which plays a role in the biosynthesis of creatine, a compound that is important for energy metabolism in muscles and other tissues. AGAT transfers an amidino group from arginine to glycine, forming guanidinoacetate and ornithine as products.

Abnormalities in the activity of amidinotransferases have been implicated in various diseases, including neurological disorders and certain genetic conditions. For example, mutations in the gene encoding AGAT have been associated with a rare inherited disorder called cerebral creatine deficiency syndrome type 1 (CCDS1), which is characterized by developmental delay, intellectual disability, and other neurological symptoms.

Pyruvate is a negatively charged ion or group of atoms, called anion, with the chemical formula C3H3O3-. It is formed from the decomposition of glucose and other sugars in the process of cellular respiration. Pyruvate plays a crucial role in the metabolic pathways that generate energy for cells.

In the cytoplasm, pyruvate is produced through glycolysis, where one molecule of glucose is broken down into two molecules of pyruvate, releasing energy and producing ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide).

In the mitochondria, pyruvate can be further metabolized through the citric acid cycle (also known as the Krebs cycle) to produce more ATP. The process involves the conversion of pyruvate into acetyl-CoA, which then enters the citric acid cycle and undergoes a series of reactions that generate energy in the form of ATP, NADH, and FADH2 (reduced flavin adenine dinucleotide).

Overall, pyruvate is an important intermediate in cellular respiration and plays a central role in the production of energy for cells.

Adenylate kinase is an enzyme (EC 2.7.4.3) that catalyzes the reversible transfer of a phosphate group between adenine nucleotides, specifically between ATP and AMP to form two ADP molecules. This reaction plays a crucial role in maintaining the energy charge of the cell by interconverting these important energy currency molecules.

The general reaction catalyzed by adenylate kinase is:

AMP + ATP ↔ 2ADP

This enzyme is widely distributed in various organisms and tissues, including mammalian cells. In humans, there are several isoforms of adenylate kinase, located in different cellular compartments such as the cytosol, mitochondria, and nucleus. These isoforms have distinct roles in maintaining energy homeostasis and protecting cells under stress conditions. Dysregulation of adenylate kinase activity has been implicated in several pathological processes, including neurodegenerative diseases, ischemia-reperfusion injury, and cancer.

Anoxia is a medical condition that refers to the absence or complete lack of oxygen supply in the body or a specific organ, tissue, or cell. This can lead to serious health consequences, including damage or death of cells and tissues, due to the vital role that oxygen plays in supporting cellular metabolism and energy production.

Anoxia can occur due to various reasons, such as respiratory failure, cardiac arrest, severe blood loss, carbon monoxide poisoning, or high altitude exposure. Prolonged anoxia can result in hypoxic-ischemic encephalopathy, a serious condition that can cause brain damage and long-term neurological impairments.

Medical professionals use various diagnostic tests, such as blood gas analysis, pulse oximetry, and electroencephalography (EEG), to assess oxygen levels in the body and diagnose anoxia. Treatment for anoxia typically involves addressing the underlying cause, providing supplemental oxygen, and supporting vital functions, such as breathing and circulation, to prevent further damage.

Brain ischemia is the medical term used to describe a reduction or interruption of blood flow to the brain, leading to a lack of oxygen and glucose delivery to brain tissue. This can result in brain damage or death of brain cells, known as infarction. Brain ischemia can be caused by various conditions such as thrombosis (blood clot formation), embolism (obstruction of a blood vessel by a foreign material), or hypoperfusion (reduced blood flow). The severity and duration of the ischemia determine the extent of brain damage. Symptoms can range from mild, such as transient ischemic attacks (TIAs or "mini-strokes"), to severe, including paralysis, speech difficulties, loss of consciousness, and even death. Immediate medical attention is required for proper diagnosis and treatment to prevent further damage and potential long-term complications.

The Quadriceps muscle, also known as the Quadriceps Femoris, is a large muscle group located in the front of the thigh. It consists of four individual muscles - the Rectus Femoris, Vastus Lateralis, Vastus Intermedius, and Vastus Medialis. These muscles work together to extend the leg at the knee joint and flex the thigh at the hip joint. The Quadriceps muscle is crucial for activities such as walking, running, jumping, and kicking.

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

The cell's ability to generate phosphocreatine from excess ATP during rest, as well as its use of phosphocreatine for quick ... Once inside the cells it is transformed into phosphocreatine by the enzyme complex creatine kinase. Phosphocreatine is able to ... Phosphocreatine can be broken down into creatinine, which is then excreted in the urine. A 70 kg man contains around 120 g of ... Phosphocreatine can anaerobically donate a phosphate group to ADP to form ATP during the first five to eight seconds of a ...
Phosphocreatine is formed naturally within the body, with over 95% of the compound stored within the muscle cells. The body ... The substance was found to be neoton (phosphocreatine), which is used in cardiac surgery to protect the heart during periods of ... "Phosphocreatine". Faqs.org. Retrieved 7 June 2010. "Cannavaro injection video troubles Italian sports executive". Yahoo! Sports ...
This makes conversion of creatine to phosphocreatine a highly favored reaction. Phosphocreatine is a very-high-energy compound ... Thus, phosphocreatine breaks down to creatine, giving its inorganic phosphate for ATP formation. This is done by the enzyme ... This is part of phosphocreatine metabolism. In mitochondria, Adenosine triphosphate (ATP) levels are very high as a result of ... At the onset of exercise phosphocreatine is broken down to provide ATP for muscle contraction. ATP hydrolysis results in ...
The discovery of phosphocreatine was reported in 1927. In the 1960s, creatine kinase (CK) was shown to phosphorylate ADP using ... The typical creatine content of skeletal muscle (as both creatine and phosphocreatine) is 120 mmol per kilogram of dry muscle ... Creatine itself can be phosphorylated by creatine kinase to form phosphocreatine, which is used as an energy buffer in skeletal ... 95% of the human body's total creatine and phosphocreatine stores are found in skeletal muscle, while the remainder is ...
... it becomes the high-energy compound phosphocreatine. Creatine conversion to phosphocreatine is catalyzed by creatine kinase; ... Creatinine itself is produced via a biological system involving creatine, phosphocreatine (also known as creatine phosphate), ...
Phosphocreatine is used in the phosphagen system to produce ATP. The study found that low creatine and low phosphocreatine were ... The fibromyalgia patients were found to have lower phosphocreatine (PCr) and lower creatine (Cr) than the control group. ... and phosphocreatine, and increased levels of AMP and creatine (use of creatine kinase and myokinase in the phosphagen system ... Low phosphocreatine levels may disrupt glutamate neurotransmission within the brains of those with fibromyalgia. Glutamate/ ...
Another was Otto Folin, an American chemist who discovered Phosphocreatine. In 1923, Kossel was honored by being named ...
Mora B.; Narasimhan P.T.; Ross B.D.; Allman J.; Barker P. B. (1991). "P Saturation Transfer and Phosphocreatine Imaging in the ...
Kekelidze T, Khait I, Togliatti A, Benzecry JM, Wieringa B, Holtzman D (December 2001). "Altered brain phosphocreatine and ATP ...
Bogdanis, GC; Nevill, ME; Boobis, LH; Lakomy, HK (1 March 1996). "Contribution of phosphocreatine and aerobic metabolism to ... Possible physiological advantages from RSH include compensatory vasodilation and regeneration of phosphocreatine (PCr). The ...
The functions of these isoenzymes are to convert creatine, using ATP, into phosphocreatine expelling ADP. Mini columns were ...
The quick energy sources consist of the phosphocreatine (PCr) system, fast glycolysis, and adenylate kinase. All of these ... This enzyme catalyzes a reaction that combines phosphocreatine and adenosine diphosphate (ADP) into ATP and creatine. This ... resource is short lasting because oxygen is required for the resynthesis of phosphocreatine via mitochondrial creatine kinase. ...
Creatine and phosphocreatine: with its major peak at 3.0 ppm, creatine marks metabolism of brain energy. Gradual loss of ...
"The Determination of Phosphorus and the Discovery of Phosphocreatine and ATP: the Work of Fiske and SubbaRow". Journal of ...
... not to be confused with phosphocreatine. v t e (Articles with changed EBI identifier, ECHA InfoCard ID from Wikidata, Articles ...
... responsible for elucidating the role of phosphocreatine in energy production in muscles. Member Natl. Acad. Sci. USA Joseph ...
Generally, there are two types of phosphagens in animals, phosphoarginine (PA) in invertebrates and phosphocreatine (PC) in ...
The increase in mean power output was attributed to creatine's ability to counteract the lack of intramuscular phosphocreatine ... such as the buildup of lactic acid and the depletion of adenosine triphosphate and phosphocreatine. Resting 3-5 minutes between ...
Two of the three depend upon the food eaten, whereas the other depends upon a chemical compound called phosphocreatine. The ... phosphocreatine circuit' for cellular energy homeostasis". The Biochemical Journal. 281 (Pt 1): 21-40. doi:10.1042/bj2810021. ... When the phosphagen system has been depleted of phosphocreatine (creatine phosphate), the resulting AMP produced from the ...
... which facilitates the reaction of ADP and phosphocreatine into ATP and creatine. The interaction between actin and myosin ...
... catalyses the interconversion of phospho creatine to creatine . CPK exists in 3 isoenzymes. Each isoenzymes is a dimer of 2 ...
... (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme (EC 2.7.3.2) expressed ... CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create phosphocreatine (PCr) and adenosine ... While mitochondrial creatine kinase is directly involved in the formation of phosphocreatine from mitochondrial ATP, cytosolic ... Mitochondrial creatine kinase (CKm) is present in the mitochondrial intermembrane space, where it regenerates phosphocreatine ( ...
Two examples of natural phosphoramidates are phosphocreatine and the phosphoramidate formed when histidine residues in ...
In affected individuals with all three disorders, there is an almost complete absence of creatine and phosphocreatine in the ...
The encoded protein reversibly catalyzes the transfer of "energy-rich" phosphate between ATP and creatine and between phospho-creatine ...
creatine + ATP ⇌ phosphocreatine + ADP + H+ The reaction is reversible as well, allowing cellular ATP levels to be maintained ...
Downregulation of genes encoding for mitochondrial subunits, decreased concentration of phosphocreatine, decreased brain pH, ...
The encoded protein reversibly catalyzes the transfer of "energy-rich" phosphate between ATP and creatine or between phospho-creatine ...
... and is responsible for transferring a phosphate group from ATP to create a phosphocreatine molecule. BCAA supplementation has ...
... generating phosphocreatine and ADP. Creatine kinase plays an important role in energy metabolism of vertebrates. There are at ...
The cells ability to generate phosphocreatine from excess ATP during rest, as well as its use of phosphocreatine for quick ... Once inside the cells it is transformed into phosphocreatine by the enzyme complex creatine kinase. Phosphocreatine is able to ... Phosphocreatine can be broken down into creatinine, which is then excreted in the urine. A 70 kg man contains around 120 g of ... Phosphocreatine can anaerobically donate a phosphate group to ADP to form ATP during the first five to eight seconds of a ...
Interactions between PPAR alpha and triiodothyronine nuclear receptors altered cardiac phenotype and phosphocreatine metabolism ... Interactions between PPAR alpha and triiodothyronine nuclear receptors altered cardiac phenotype and phosphocreatine metabolism ...
... phosphocreatine (PCr) energy buffer and transport system in heart remains unclear. Guanidinoacetate-N-methyltransferase- ... BACKGROUND: The role of the creatine kinase (CK)/phosphocreatine (PCr) energy buffer and transport system in heart remains ... Reduced inotropic reserve and increased susceptibility to cardiac ischemia/reperfusion injury in phosphocreatine-deficient ... Reduced inotropic reserve and increased susceptibility to cardiac ischemia/reperfusion injury in phosphocreatine-deficient ...
Phosphocreatine resynthesis is not affected by creatine loading. Med Sci Sports Exerc 1999;31:236-42. View abstract. ... Combined use of phosphocreatine and nifedipine for treatment of patients with acute myocardial infarction. Current Therapeutic ... Inhibition of muscle phosphocreatine resynthesis by caffeine after creatine loading. Med Sci Sports Exerc 1997;29(5 Supplement ... Creatine and phosphocreatine analogs: anticancer activity and enzymatic analysis. Oncol Res 1996;8:121-30. View abstract. ...
After exercise has stopped, extra oxygen is required to metabolize lactic acid; to replenish ATP, phosphocreatine, and glycogen ...
The intracellular content of phosphocreatine was less than 0.2 fmol/cell.. Authors. ...
Phosphocreatine can be expected to play a role in supplying energy to metabolically active areas of the brain. There are ... When creatine combines with P to form phosphocreatine, it acts as a reserve of high-energy phosphate that is used to rapidly ... Creatine when combined with P forms phosphocreatine that acts as a reserve of high-energy phosphate. Creatine is found mostly ... several isoforms of creatine phosphokinase, the enzyme that converts creatine to phosphocreatine. The most common variety is ...
In the body, creatine is formed from amino acids and replenishes phosphocreatine, an important energy source for muscle cells. ...
The brain is as equally reliant as muscles on phosphocreatine for ATP to function well. The longer brain cells have energy, the ... The brain is as equally reliant as muscles on phosphocreatine for ATP to function well. The longer brain cells have energy, the ... Creatine combines with a phosphoryl group to produce phosphocreatine. It then donates the high-energy phosphate group to ADP to ... Creatine combines with a phosphoryl group to produce phosphocreatine. It then donates the high-energy phosphate group to ADP to ...
Muscle Phosphocreatine Support! Increase Total & Fat Free Mass, Increase Isometric Muscle Stre... ... Build Fast Formula Creatine - Muscle Phosphocreatine Support! Increase Total & Fat Free Mass, Increase Isometric Muscle ...
... the phosphocreatine to inorganic phosphate ratio is reduced in resting muscle of HD patients (Koroshetz et al., 1997); (3) ...
Kappenstein, J.; Ferrauti, A.; Runkel, B.; Fernandez-Fernandez, J.; Müller, K.; Zange, J. Changes in Phosphocreatine ... lower phosphocreatine (PCr) depletion, faster PCr resynthesis rates [111,112,113,114] and faster heart rate recovery [67,75,108 ... Skeletal Muscle Phosphocreatine Recovery after Submaximal Exercise in Children and Young and Middle-Aged Adults. J. Clin. ...
In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as CREATININE in the urine. Source: ...
Creatine kinase catalyzes the conversion of creatine and consumes adenosine triphosphate (ATP) to create phosphocreatine and ...
In the liver, creatine is combined with phosphorus to form the compound creatine phosphate (phosphocreatine). ...
Skeletal muscle phosphocreatine recovery in exercise-trained humans is dependent on O2 availability ... Skeletal muscle phosphocreatine recovery in exercise-trained humans is dependent on O2 availability ... Even during anaerobic bouts, when energy is derived from the transfer of phosphate from phosphocreatine to adenosine ...
Medscape - Indication-specific dosing for amidinosarcosine, creatine citrate, creatine monohydrate, creatine phosphate, N-amidinosarcosine (creatine), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and cost information.
ATP, AMP, ADP, and phosphocreatine were measured spectrophotometrically as previously described (8). Malonyl CoA was determined ...
... fast bursts will tax your phosphocreatine system (which fuels explosive anaerobic muscle contractions) and help you develop raw ...
... which promotes replenishment of phosphocreatine stores (used to resynthesize ATP), restoration of intramuscular pH (acid/base ...
... adenosine triphosphate or phosphocreatine [13]. Rather, it was postulated that T1 changes may be related to changes in both ...
The physiological importance of the phosphocreatine circuit fully operating in adult brain has been corroborated by recent data ...
Stimulation of phosphocreatine production results in more adenosine triphosphate (ATP) for your androgenicity of the hormone ...
keywords = "muscles, age, nutrition, physical activity, transcriptomes, metabolomes, elderly, creatine, phosphocreatine, ...
It increases phosphocreatine stores in the body which helps with adenosine triphosphate (ATP) formation - the fuel that all ... During exercise, OPTIMUM NUTRITION Serious Mass replenishes your phosphocreatine stores, allowing you to make more ATP to fuel ...
10.0 Na-Phosphocreatine, 0.3 Na-GTP, 10.0 HEPES, 8.0 Biocytin; pH 7.3, 295 mOsm). The intracellular electrode (Ag/AgCl) ...
CAMH: Access CAMH all-natural chemical increases phosphocreatine synthesis and other factors like your meals and type of ...
Asc: Ascorbate/vitamin C; tCr: total creatine + phosphocreatine; GABA: gamma-aminobutyric acid; Glc: glucose; Gln: glutamine; ...
... phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that ... phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that ...
  • It increases phosphocreatine stores in the body which helps with adenosine triphosphate (ATP) formation - the fuel that all cells prefer. (silabg.com)
  • CAMH: Access CAMH all-natural chemical increases phosphocreatine synthesis and other factors like your meals and type of workouts, you gain 20-50 lbs in a year. (katherinealbrecht.com)
  • Phosphocreatine, also known as creatine phosphate (CP) or PCr (Pcr), is a phosphorylated form of creatine that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle, myocardium and the brain to recycle adenosine triphosphate, the energy currency of the cell. (wikipedia.org)
  • Once inside the cells it is transformed into phosphocreatine by the enzyme complex creatine kinase. (wikipedia.org)
  • citation needed] Conversely, excess ATP can be used during a period of low effort to convert creatine back to phosphocreatine. (wikipedia.org)
  • BACKGROUND: The role of the creatine kinase (CK)/phosphocreatine (PCr) energy buffer and transport system in heart remains unclear. (ox.ac.uk)
  • Creatine when combined with P forms phosphocreatine that acts as a reserve of high-energy phosphate. (cambridge.org)
  • In the body, creatine is formed from amino acids and replenishes phosphocreatine, an important energy source for muscle cells. (time.com)
  • Creatine combines with a phosphoryl group to produce phosphocreatine. (purebulk.com)
  • Build Fast Formula Creatine - Muscle Phosphocreatine Support! (a1supplements.com)
  • In muscle tissue, creatine generally occurs as phosphocreatine. (loinc.org)
  • During exercise, OPTIMUM NUTRITION Serious Mass replenishes your phosphocreatine stores, allowing you to make more ATP to fuel your muscles. (silabg.com)
  • Phosphocreatine is able to donate its phosphate group to convert adenosine diphosphate (ADP) into adenosine triphosphate (ATP). (wikipedia.org)
  • Stimulation of phosphocreatine production results in more adenosine triphosphate (ATP) for your androgenicity of the hormone many women will avoid virilization. (htdig.org)
  • The physiological importance of the phosphocreatine circuit fully operating in adult brain has been corroborated by recent data from in vivo 31 P-NMR magnetization transfer measurements. (karger.com)
  • Phosphocreatine can be broken down into creatinine, which is then excreted in the urine. (wikipedia.org)
  • Reduced inotropic reserve and increased susceptibility to cardiac ischemia/reperfusion injury in phosphocreatine-deficient guanidinoacetate-N-methyltransferase-knockout mice. (ox.ac.uk)
  • The cell's ability to generate phosphocreatine from excess ATP during rest, as well as its use of phosphocreatine for quick regeneration of ATP during intense activity, provides a spatial and temporal buffer of ATP concentration. (wikipedia.org)
  • The brain is as equally reliant as muscles on phosphocreatine for ATP to function well. (purebulk.com)
  • This muscle burn or buildup of hydrogen ions make the muscles and blood highly acidic, which interferes with phosphocreatine resynthesis and inhibits glycolysis. (ironmanmagazine.com)
  • Phosphocreatine plays a particularly important role in tissues that have high, fluctuating energy demands such as muscle and brain. (wikipedia.org)
  • Finally, short, fast bursts will tax your phosphocreatine system (which fuels explosive anaerobic muscle contractions) and help you develop raw speed and power. (trainingpeaks.com)
  • During exercise, recovery is needed to reestablish intramuscular blood flow for oxygen delivery, which promotes replenishment of phosphocreatine stores (used to resynthesize ATP), restoration of intramuscular pH (acid/base balance), and regaining of muscle membrane potential (balance between sodium and potassium exchanges inside and outside of cell) (Weiss, 1991). (unm.edu)