Homovanillic acid (HVA) is a major metabolite of dopamine, formed in the body through the catabolic breakdown of this neurotransmitter by the enzyme catechol-O-methyltransferase and then further metabolized in the liver before excretion in urine.
Derivatives of phenylacetic acid. Included under this heading are a variety of acid forms, salts, esters, and amides that contain the benzeneacetic acid structure. Note that this class of compounds should not be confused with derivatives of phenyl acetate, which contain the PHENOL ester of ACETIC ACID.
Vanilmandelic acid (VMA) is a major metabolite of catecholamines, specifically normetanephrine and metanephrine, which are produced by the adrenal gland and can be measured in urine to help diagnose pheochromocytoma or neuroblastoma.
Hydroxyindoleacetic acid (5HIAA) is a major metabolite of serotonin, a neurotransmitter, formed by the action of monoamine oxidase and aldehyde dehydrogenase, and its measurement in urine is often used as a biomarker for serotonin synthesis in clinical and research settings.
A deaminated metabolite of LEVODOPA.
Synthesized from endogenous epinephrine and norepinephrine in vivo. It is found in brain, blood, CSF, and urine, where its concentrations are used to measure catecholamine turnover.
Biogenic amines having only one amine moiety. Included in this group are all natural monoamines formed by the enzymatic decarboxylation of natural amino acids.
One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.
A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.
An isoquinoline derivative that prevents dopamine reuptake into synaptosomes. The maleate was formerly used in the treatment of depression. It was withdrawn worldwide in 1986 due to the risk of acute hemolytic anemia with intravascular hemolysis resulting from its use. In some cases, renal failure also developed. (From Martindale, The Extra Pharmacopoeia, 30th ed, p266)
An inhibitor of DOPA DECARBOXYLASE, preventing conversion of LEVODOPA to dopamine. It is used in PARKINSON DISEASE to reduce peripheral adverse effects of LEVODOPA. It has no antiparkinson actions by itself.
A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific.
Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.
A group of naturally occurring amines derived by enzymatic decarboxylation of the natural amino acids. Many have powerful physiological effects (e.g., histamine, serotonin, epinephrine, tyramine). Those derived from aromatic amino acids, and also their synthetic analogs (e.g., amphetamine), are of use in pharmacology.
The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.
A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)
A hypnotic and sedative. Its use has been largely superseded by other drugs.
A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.
A central nervous system stimulant used in fatigue and depressive states and to treat hyperkinetic disorders in children.
A technique for measuring extracellular concentrations of substances in tissues, usually in vivo, by means of a small probe equipped with a semipermeable membrane. Substances may also be introduced into the extracellular space through the membrane.
An indirect sympathomimetic. Tyramine does not directly activate adrenergic receptors, but it can serve as a substrate for adrenergic uptake systems and monoamine oxidase so it prolongs the actions of adrenergic transmitters. It also provokes transmitter release from adrenergic terminals. Tyramine may be a neurotransmitter in some invertebrate nervous systems.
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.
A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.
A common neoplasm of early childhood arising from neural crest cells in the sympathetic nervous system, and characterized by diverse clinical behavior, ranging from spontaneous remission to rapid metastatic progression and death. This tumor is the most common intraabdominal malignancy of childhood, but it may also arise from thorax, neck, or rarely occur in the central nervous system. Histologic features include uniform round cells with hyperchromatic nuclei arranged in nests and separated by fibrovascular septa. Neuroblastomas may be associated with the opsoclonus-myoclonus syndrome. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2099-2101; Curr Opin Oncol 1998 Jan;10(1):43-51)
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
The prototypical uricosuric agent. It inhibits the renal excretion of organic anions and reduces tubular reabsorption of urate. Probenecid has also been used to treat patients with renal impairment, and, because it reduces the renal tubular excretion of other drugs, has been used as an adjunct to antibacterial therapy.
The prototypical phenothiazine antipsychotic drug. Like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking DOPAMINE RECEPTORS. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup.
An inhibitor of DOPA DECARBOXYLASE that does not enter the central nervous system. It is often given with LEVODOPA in the treatment of parkinsonism to prevent the conversion of levodopa to dopamine in the periphery, thereby increasing the amount that reaches the central nervous system and reducing the required dose. It has no antiparkinson actions when given alone.
A monoamine oxidase inhibitor with antihypertensive properties.
An inhibitor of the enzyme TYROSINE 3-MONOOXYGENASE, and consequently of the synthesis of catecholamines. It is used to control the symptoms of excessive sympathetic stimulation in patients with PHEOCHROMOCYTOMA. (Martindale, The Extra Pharmacopoeia, 30th ed)
A group of compounds that are methyl derivatives of the amino acid TYROSINE.
An enzyme that catalyzes the oxidative deamination of naturally occurring monoamines. It is a flavin-containing enzyme that is localized in mitochondrial membranes, whether in nerve terminals, the liver, or other organs. Monoamine oxidase is important in regulating the metabolic degradation of catecholamines and serotonin in neural or target tissues. Hepatic monoamine oxidase has a crucial defensive role in inactivating circulating monoamines or those, such as tyramine, that originate in the gut and are absorbed into the portal circulation. (From Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 8th ed, p415) EC 1.4.3.4.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A chemically heterogeneous group of drugs that have in common the ability to block oxidative deamination of naturally occurring monoamines. (From Gilman, et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p414)
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
A process of selective diffusion through a membrane. It is usually used to separate low-molecular-weight solutes which diffuse through the membrane from the colloidal and high-molecular-weight solutes which do not. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant.
Enzyme that catalyzes the movement of a methyl group from S-adenosylmethionone to a catechol or a catecholamine.
Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.
An enzyme that catalyzes the conversion of L-tyrosine, tetrahydrobiopterin, and oxygen to 3,4-dihydroxy-L-phenylalanine, dihydrobiopterin, and water. EC 1.14.16.2.
A condition caused by the neurotoxin MPTP which causes selective destruction of nigrostriatal dopaminergic neurons. Clinical features include irreversible parkinsonian signs including rigidity and bradykinesia (PARKINSON DISEASE, SECONDARY). MPTP toxicity is also used as an animal model for the study of PARKINSON DISEASE. (Adams et al., Principles of Neurology, 6th ed, p1072; Neurology 1986 Feb;36(2):250-8)
The phylogenetically newer part of the CORPUS STRIATUM consisting of the CAUDATE NUCLEUS and PUTAMEN. It is often called simply the striatum.
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.
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.
A progressive, degenerative neurologic disease characterized by a TREMOR that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression. Pathologic features include loss of melanin containing neurons in the substantia nigra and other pigmented nuclei of the brainstem. LEWY BODIES are present in the substantia nigra and locus coeruleus but may also be found in a related condition (LEWY BODY DISEASE, DIFFUSE) characterized by dementia in combination with varying degrees of parkinsonism. (Adams et al., Principles of Neurology, 6th ed, p1059, pp1067-75)
Any drugs that are used for their effects on dopamine receptors, on the life cycle of dopamine, or on the survival of dopaminergic neurons.

Kinetics of oxidation of aliphatic and aromatic thiols by myeloperoxidase compounds I and II. (1/435)

Myeloperoxidase (MPO) is the most abundant protein in neutrophils and plays a central role in microbial killing and inflammatory tissue damage. Because most of the non-steroidal anti-inflammatory drugs and other drugs contain a thiol group, it is necessary to understand how these substrates are oxidized by MPO. We have performed transient kinetic measurements to study the oxidation of 14 aliphatic and aromatic mono- and dithiols by the MPO intermediates, Compound I (k3) and Compound II (k4), using sequential mixing stopped-flow techniques. The one-electron reduction of Compound I by aromatic thiols (e.g. methimidazole, 2-mercaptopurine and 6-mercaptopurine) varied by less than a factor of seven (between 1.39 +/- 0.12 x 10(5) M(-1) s(-1) and 9.16 +/- 1.63 x 10(5) M(-1) s(-1)), whereas reduction by aliphatic thiols was demonstrated to depend on their overall net charge and hydrophobic character and not on the percentage of thiol deprotonation or redox potential. Cysteamine, cysteine methyl ester, cysteine ethyl ester and alpha-lipoic acid showed k3 values comparable to aromatic thiols, whereas a free carboxy group (e.g. cysteine, N-acetylcysteine, glutathione) diminished k3 dramatically. The one-electron reduction of Compound II was far more constrained by the nature of the substrate. Reduction by methimidazole, 2-mercaptopurine and 6-mercaptopurine showed second-order rate constants (k4) of 1.33 +/- 0.08 x 10(5) M(-1) s(-1), 5.25 +/- 0.07 x 10(5) M(-1) s(-1) and 3.03 +/- 0.07 x 10(3) M(-1) s(-1). Even at high concentrations cysteine, penicillamine and glutathione could not reduce Compound II, whereas cysteamine (4.27 +/- 0.05 x 10(3) M(-1) s(-1)), cysteine methyl ester (8.14 +/- 0.08 x 10(3) M(-1) s(-1)), cysteine ethyl ester (3.76 +/- 0.17 x 10(3) M(-1) s(-1)) and alpha-lipoic acid (4.78 +/- 0.07 x 10(4) M(-1) s(-1)) were demonstrated to reduce Compound II and thus could be expected to be oxidized by MPO without co-substrates.  (+info)

Dopamine correlates of neurological and psychological status in untreated Parkinsonism. (2/435)

Thirty-seven untreated Parkinsonism patients showed significant positive correlations among decreased excretion of free dopamine, MMPI scores indicative of schizophrenic-like looseness of thinking, and the severity of all Parkinsonism signs except tremor. The data could indicate that abnormalities of dopamine metabolism may underlie both the motor and mental abnormalities of Parkinsonism.  (+info)

Improvement by nefiracetam of beta-amyloid-(1-42)-induced learning and memory impairments in rats. (3/435)

1. We have previously demonstrated that continuous i.c.v. infusion of amyloid beta-peptide (A beta), the major constituent of senile plaques in the brains of patients with Alzheimer's disease, results in learning and memory deficits in rats. 2. In the present study, we investigated the effects of nefiracetam [N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, DM-9384] on A beta-(1-42)-induced learning and memory deficits in rats. 3. In the A beta-(1-42)-infused rats, spontaneous alternation behaviour in a Y-maze task, spatial reference and working memory in a water maze task, and retention of passive avoidance learning were significantly impaired as compared with A beta-(40-1)-infused control rats. 4. Nefiracetam, at a dose range of 1-10 mg kg(-1), improved learning and memory deficits in the A beta-(1-42)-infused rats when it was administered p.o. 1 h before the behavioural tests. 5. Nefiracetam at a dose of 3 mg kg(-1) p.o. increased the activity of choline acetyltransferase in the hippocampus of A beta-(1-42)-infused rats. 6. Nefiracetam increased dopamine turnover in the cerebral cortex and striatum of A beta-(1-42)-infused rats, but failed to affect the noradrenaline, serotonin and 5-hydroxyindoleacetic acid content. 7. These results suggest that nefiracetam may be useful for the treatment of patients with Alzheimer's disease.  (+info)

Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls. (4/435)

We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.  (+info)

Spinal reflexes and the concentrations of 5-HIAA, MHPG, and HVA in lumbar cereborspinal fluid after spinal lesions in man. (5/435)

Descending bulbospinal pathways that employ specific neurotransmitter substances are known to be capable of modulating segmental reflex activity in the experimental animal. To determine whether this might also occur in man correlations have been sought between the activity in spinal reflex pathways and the lumbar cerebrospinal fluid (CSF) concentrations of 5-hydroxyindolacetic acid (5-HIAA), 3 methoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA) in 12 patients with complete or virtually complete spinal lesions. The concentrations of 5-HIAA and MHPG in lumbar CSF ARE REDUCED AFTER COMPLETE OR VIRTUALLY COMPLETE SPINAL LESIONS IN MAN. This may occur within 18 days of the lesion. MHPG concentrations appear to be inversely related to the level of the lesion. The HVA concentration in lumbar CSF is reduced when there is obstruction of the CSF pathways. No relationship could be demonstrated between the concentrations of 5-HIAA or MHPG in lumbar CSF and the activity in the spinal monosynaptic pathway (estimated from the proportion of the motoneurone pool activated by the Achilles tendon reflex or H reflex) or the activity of a spinal inhibitory mechanism (estimated by the degree of vibratory inhibition of the monosynaptic reflex). Patients with a tonic vibration reflex (TVR) tended to have higher MHPG levels. There appeared to be an association between low CSF HVA and enhanced vibratory inhibition of the monosynaptic reflex in the nine patients whose spinal lesions were complete.  (+info)

Failure to thrive and death in early infancy associated with raised urinary homovanillic and vanillylmandelic acids. (6/435)

A case of failure to thrive in an infant with persistently raised urinary levels of homovanillic and vanillylmandelic acids is descirbed. No neural crest tumour was discovered at surgical exploration or at necropsy. The relation of this biochemical abnormality and failure to thrive is unclear.  (+info)

Increased dopaminergic and 5-hydroxytryptaminergic activities in male rat brain following long-term treatment with anabolic androgenic steroids. (7/435)

1. The effects of treating groups of rats with four different anabolic androgenic steroids (AAS) (testosterone, nandrolone, methandrostenolone, and oxymetholone) on 5-hydroxytryptamine (5-HT) and dopamine (DA) neurones in different brain regions were examined. The AAS was injected six times with 1 week's interval and the rats were sacrificed 2 days after the final injection. 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), DA and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured. The effect on DA and 5-HT synthesis rate was analysed as the accumulation of 3,4-dihydroxyphenyl-alanine (DOPA) and 5-hydroxytryptophan (5-HTP), respectively, after inhibition of the amino acid decarboxylase with NSD-1015 (3-hydroxy-benzylhydrazine dihydrochloride). Additionally, the monoamine oxidase (MAO) activity was analysed in the hypothalamus. 2. The DOPAC + HVA/DA ratio was increased in the striatum in all treatment groups. However, the synthesis rate of DA was significantly increased only in the methandrostenolone treated group. 3. The 5-HIAA/5-HT ratio was increased in all treatment groups in the hippocampus, in the frontal cortex in the methandrostenolone-treated animals and in the hypothalamus in the testosterone- and oxymetholone-treated rats, while the 5-HT synthesis rate was not affected by the AAS-treatments. 4. The MAO-A activity was increased in the oxymetholone-treated rats while the other treatment groups were unaffected. The MAO-B activity was not changed. 5. The results indicate that relatively high doses of AAS increase dopaminergic and 5-hydroxytryptaminergic metabolism in male rat brain, probably due to enhanced turnover in these monaminergic systems.  (+info)

Cerebrospinal fluid monoaminergic metabolites differ in wild anubis and hybrid (Anubis hamadryas) baboons: possible relationships to life history and behavior. (8/435)

The article reports monoaminergic metabolite [homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MHPG)], values from the cerebrospinal fluid (CSF) of 27 wild baboons (Papio hamadryas) aged 40 to 140 months. Animals were either anubis, or anubis with hamadryas admixture; males of the latter subspecies generally have a reduced tendency to disperse from their natal groups. Overall, the values and interrelationships among the CSF monoamine metabolites resembled data reported from closely related, captive-housed animals. For example, age was significantly correlated with HVA concentrations (r = -60, p < .05), but not with the other metabolites. Notably, males characterized by hamadryas admixture had significantly higher concentrations of HVA, 5-HIAA, and MHPG (p < .05, respectively), a result possibly driven by differences in serotonergic activity. These data provide initial evidence that variation in central monoaminergic activity, as indicated by CSF monoamine metabolite concentrations, may reflect differences in behavior and life history that have taxonomic and, perhaps, evolutionary significance.  (+info)

Homovanillic acid (HVA) is a major metabolite of dopamine, a neurotransmitter in the human body. It is formed in the body when an enzyme called catechol-O-methyltransferase (COMT) breaks down dopamine. HVA can be measured in body fluids such as urine, cerebrospinal fluid, and plasma to assess the activity of dopamine and the integrity of the dopaminergic system. Increased levels of HVA are associated with certain neurological disorders, including Parkinson's disease, while decreased levels may indicate dopamine deficiency or other conditions affecting the nervous system.

Phenylacetates are a group of organic compounds that contain a phenyl group (a benzene ring with a hydroxyl group) and an acetic acid group. In the context of medicine, sodium phenylacetate is used in the treatment of certain metabolic disorders, such as urea cycle disorders, to help remove excess ammonia from the body. It does this by conjugating with glycine to form phenylacetylglutamine, which can then be excreted in the urine.

It is important to note that the use of phenylacetates should be under the supervision of a medical professional, as improper use or dosage can lead to serious side effects.

Vanilmandelic acid (VMA) is a metabolite produced in the body as a result of the breakdown of catecholamines, which are hormones such as dopamine, norepinephrine, and epinephrine. Specifically, VMA is the major end product of epinephrine and norepinephrine metabolism.

In clinical medicine, measurement of VMA in urine is often used as a diagnostic test for pheochromocytoma, a rare tumor that arises from the chromaffin cells of the adrenal gland and can cause excessive production of catecholamines. Elevated levels of VMA in the urine may indicate the presence of a pheochromocytoma or other conditions associated with increased catecholamine secretion, such as neuroblastoma or ganglioneuroma.

It's important to note that while VMA is a useful diagnostic marker for pheochromocytoma and related conditions, it is not specific to these disorders and can be elevated in other medical conditions as well. Therefore, the test should be interpreted in conjunction with other clinical findings and diagnostic tests.

Hydroxyindoleacetic acid (5HIAA) is a major metabolite of the neurotransmitter serotonin, formed in the body through the enzymatic degradation of serotonin by monoamine oxidase and aldehyde dehydrogenase. 5HIAA is primarily excreted in the urine and its measurement can be used as a biomarker for serotonin synthesis and metabolism in the body.

Increased levels of 5HIAA in the cerebrospinal fluid or urine may indicate conditions associated with excessive serotonin production, such as carcinoid syndrome, while decreased levels may be seen in certain neurodegenerative disorders, such as Parkinson's disease. Therefore, measuring 5HIAA levels can have diagnostic and therapeutic implications for these conditions.

3,4-Dihydroxyphenylacetic Acid (3,4-DOPAC) is a major metabolite of dopamine, which is a neurotransmitter in the brain. Dopamine is metabolized by the enzyme monoamine oxidase to form dihydroxyphenylacetaldehyde, which is then further metabolized to 3,4-DOPAC by the enzyme aldehyde dehydrogenase.

3,4-DOPAC is found in the urine and can be used as a marker for dopamine turnover in the brain. Changes in the levels of 3,4-DOPAC have been associated with various neurological disorders such as Parkinson's disease and schizophrenia. Additionally, 3,4-DOPAC has been shown to have antioxidant properties and may play a role in protecting against oxidative stress in the brain.

Methoxyhydroxyphenylglycol (MHPG) is a major metabolite of the neurotransmitter norepinephrine, which is synthesized in the body from the amino acid tyrosine. Norepinephrine plays important roles in various physiological functions such as the cardiovascular system, respiratory system, and central nervous system. MHPG is formed when norepinephrine is metabolized by enzymes called catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO).

MHPG is primarily found in the urine, and its levels can be measured to assess norepinephrine turnover in the body. Changes in MHPG levels have been associated with various medical conditions, including depression, anxiety disorders, and neurodegenerative diseases such as Parkinson's disease. However, the clinical utility of measuring MHPG levels is still a subject of ongoing research and debate.

Biogenic monoamines are a type of neurotransmitter, which are chemical messengers that transmit signals in the brain and other parts of the nervous system. They are called "biogenic" because they are derived from biological substances, and "monoamines" because they contain one amine group (-NH2) and are derived from the aromatic amino acids: tryptophan, tyrosine, and phenylalanine.

Examples of biogenic monoamines include:

1. Serotonin (5-hydroxytryptamine or 5-HT): synthesized from the amino acid tryptophan and plays a crucial role in regulating mood, appetite, sleep, memory, and learning.
2. Dopamine: formed from tyrosine and is involved in reward, motivation, motor control, and reinforcement of behavior.
3. Norepinephrine (noradrenaline): also derived from tyrosine and functions as a neurotransmitter and hormone that modulates attention, arousal, and stress responses.
4. Epinephrine (adrenaline): synthesized from norepinephrine and serves as a crucial hormone and neurotransmitter in the body's fight-or-flight response to stress or danger.
5. Histamine: produced from the amino acid histidine, it acts as a neurotransmitter and mediates allergic reactions, immune responses, and regulates wakefulness and appetite.

Imbalances in biogenic monoamines have been linked to various neurological and psychiatric disorders, such as depression, anxiety, Parkinson's disease, and schizophrenia. Therefore, medications that target these neurotransmitters, like selective serotonin reuptake inhibitors (SSRIs) for depression or levodopa for Parkinson's disease, are often used in the treatment of these conditions.

Dopamine is a type of neurotransmitter, which is a chemical messenger that transmits signals in the brain and nervous system. It plays several important roles in the body, including:

* Regulation of movement and coordination
* Modulation of mood and motivation
* Control of the reward and pleasure centers of the brain
* Regulation of muscle tone
* Involvement in memory and attention

Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area. It is released by neurons (nerve cells) and binds to specific receptors on other neurons, where it can either excite or inhibit their activity.

Abnormalities in dopamine signaling have been implicated in several neurological and psychiatric conditions, including Parkinson's disease, schizophrenia, and addiction.

Glycols are a type of organic compound that contain two hydroxyl (OH) groups attached to adjacent carbon atoms. They are colorless, odorless, and have a sweet taste. The most common glycols are ethylene glycol and propylene glycol. Ethylene glycol is widely used as an automotive antifreeze and in the manufacture of polyester fibers and resins, while propylene glycol is used as a food additive, in pharmaceuticals, and as a solvent in various industries. Glycols are also used as a coolant, humectant, and in the production of unsaturated polyester resins. Exposure to high levels of glycols can cause irritation to the eyes, skin, and respiratory tract, and ingestion can be harmful or fatal.

Nomifensine is a medication that was previously used in the treatment of depression, but it is no longer available in many countries due to safety concerns. It is a non-tricyclic antidepressant that works by inhibiting the reuptake of dopamine and noradrenaline, which helps to increase the levels of these neurotransmitters in the brain and improve mood.

The medical definition of Nomifensine is:

"Nomifensine is a non-tricyclic antidepressant that is a potent inhibitor of dopamine and noradrenaline reuptake, with minimal effects on serotonin reuptake. It was used in the treatment of depression but has been withdrawn from the market due to safety concerns."

It's important to note that Nomifensine should only be taken under the supervision of a medical professional, and it is not available in many countries due to its potential for causing serious side effects such as liver toxicity and the risk of developing a rare but potentially fatal condition called hemolytic anemia.

Carbidopa is a peripheral decarboxylase inhibitor used in the treatment of Parkinson's disease. It works by preventing the conversion of levodopa to dopamine outside of the brain, allowing more levodopa to reach the brain and reduce the symptoms of Parkinson's disease. Carbidopa is often combined with levodopa in medication formulations and is available under various brand names, such as Sinemet.

Here are some key points about carbidopa:

* It is a peripheral decarboxylase inhibitor that prevents the conversion of levodopa to dopamine outside of the brain.
* Carbidopa is often combined with levodopa in medication formulations for the treatment of Parkinson's disease.
* By preventing the conversion of levodopa to dopamine outside of the brain, more levodopa can reach the brain and reduce the symptoms of Parkinson's disease.
* Common side effects of carbidopa include nausea, vomiting, and orthostatic hypotension.
* Carbidopa should be used under the guidance of a healthcare professional and dosed appropriately to minimize side effects and maximize therapeutic benefit.

Dihydroxyphenylalanine is not a medical term per se, but it is a chemical compound that is often referred to in the context of biochemistry and neuroscience. It is also known as levodopa or L-DOPA for short.

L-DOPA is a precursor to dopamine, a neurotransmitter that plays a critical role in regulating movement, emotion, and cognition. In the brain, L-DOPA is converted into dopamine through the action of an enzyme called tyrosine hydroxylase.

L-DOPA is used medically to treat Parkinson's disease, a neurological disorder characterized by motor symptoms such as tremors, rigidity, and bradykinesia (slowness of movement). In Parkinson's disease, the dopamine-producing neurons in the brain gradually degenerate, leading to a deficiency of dopamine. By providing L-DOPA as a replacement therapy, doctors can help alleviate some of the symptoms of the disease.

It is important to note that L-DOPA has potential side effects and risks, including nausea, dizziness, and behavioral changes. Long-term use of L-DOPA can also lead to motor complications such as dyskinesias (involuntary movements) and fluctuations in response to the medication. Therefore, it is typically used in combination with other medications and under the close supervision of a healthcare provider.

The corpus striatum is a part of the brain that plays a crucial role in movement, learning, and cognition. It consists of two structures called the caudate nucleus and the putamen, which are surrounded by the external and internal segments of the globus pallidus. Together, these structures form the basal ganglia, a group of interconnected neurons that help regulate voluntary movement.

The corpus striatum receives input from various parts of the brain, including the cerebral cortex, thalamus, and other brainstem nuclei. It processes this information and sends output to the globus pallidus and substantia nigra, which then project to the thalamus and back to the cerebral cortex. This feedback loop helps coordinate and fine-tune movements, allowing for smooth and coordinated actions.

Damage to the corpus striatum can result in movement disorders such as Parkinson's disease, Huntington's disease, and dystonia. These conditions are characterized by abnormal involuntary movements, muscle stiffness, and difficulty initiating or controlling voluntary movements.

Biogenic amines are organic compounds that are derived from the metabolic pathways of various biological organisms, including humans. They are formed by the decarboxylation of amino acids, which are the building blocks of proteins. Some examples of biogenic amines include histamine, serotonin, dopamine, and tyramine.

Histamine is a biogenic amine that plays an important role in the immune system's response to foreign invaders, such as allergens. It is also involved in regulating stomach acid production and sleep-wake cycles. Serotonin is another biogenic amine that acts as a neurotransmitter, transmitting signals between nerve cells in the brain. It is involved in regulating mood, appetite, and sleep.

Dopamine is a biogenic amine that functions as a neurotransmitter and is involved in reward and pleasure pathways in the brain. Tyramine is a biogenic amine that is found in certain foods, such as aged cheeses and fermented soy products. It can cause an increase in blood pressure when consumed in large quantities.

Biogenic amines can have various effects on the body, depending on their type and concentration. In general, they play important roles in many physiological processes, but high levels of certain biogenic amines can be harmful and may cause symptoms such as headache, nausea, and hypertension.

Levodopa, also known as L-dopa, is a medication used primarily in the treatment of Parkinson's disease. It is a direct precursor to the neurotransmitter dopamine and works by being converted into dopamine in the brain, helping to restore the balance between dopamine and other neurotransmitters. This helps alleviate symptoms such as stiffness, tremors, spasms, and poor muscle control. Levodopa is often combined with carbidopa (a peripheral decarboxylase inhibitor) to prevent the conversion of levodopa to dopamine outside of the brain, reducing side effects like nausea and vomiting.

Haloperidol is an antipsychotic medication, which is primarily used to treat schizophrenia and symptoms of psychosis, such as delusions, hallucinations, paranoia, or disordered thought. It may also be used to manage Tourette's disorder, tics, agitation, aggression, and hyperactivity in children with developmental disorders.

Haloperidol works by blocking the action of dopamine, a neurotransmitter in the brain, which helps to regulate mood and behavior. It is available in various forms, including tablets, liquid, and injectable solutions. The medication can cause side effects such as drowsiness, restlessness, muscle stiffness, and uncontrolled movements. In rare cases, it may also lead to more serious neurological side effects.

As with any medication, haloperidol should be taken under the supervision of a healthcare provider, who will consider the individual's medical history, current medications, and other factors before prescribing it.

Glutethimide is a sedative-hypnotic drug that was previously used for the treatment of insomnia and anxiety disorders. It belongs to the class of drugs known as non-barbiturate hypnotics. Glutethimide works by depressing the central nervous system (CNS), producing a calming effect on the brain.

Due to its potential for abuse, addiction, and its narrow therapeutic index, glutethimide is no longer commonly used in clinical practice. It has been replaced by safer and more effective sleep aids with fewer side effects and lower potential for misuse.

It's important to note that the use of glutethimide should be under the strict supervision of a healthcare professional, and it should only be taken as prescribed. Misuse or overuse of this medication can lead to serious health consequences, including respiratory depression, coma, and even death.

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter that is found primarily in the gastrointestinal (GI) tract, blood platelets, and the central nervous system (CNS) of humans and other animals. It is produced by the conversion of the amino acid tryptophan to 5-hydroxytryptophan (5-HTP), and then to serotonin.

In the CNS, serotonin plays a role in regulating mood, appetite, sleep, memory, learning, and behavior, among other functions. It also acts as a vasoconstrictor, helping to regulate blood flow and blood pressure. In the GI tract, it is involved in peristalsis, the contraction and relaxation of muscles that moves food through the digestive system.

Serotonin is synthesized and stored in serotonergic neurons, which are nerve cells that use serotonin as their primary neurotransmitter. These neurons are found throughout the brain and spinal cord, and they communicate with other neurons by releasing serotonin into the synapse, the small gap between two neurons.

Abnormal levels of serotonin have been linked to a variety of disorders, including depression, anxiety, schizophrenia, and migraines. Medications that affect serotonin levels, such as selective serotonin reuptake inhibitors (SSRIs), are commonly used to treat these conditions.

Pemoline is a central nervous system stimulant that was used in the treatment of attention deficit hyperactivity disorder (ADHD). It is a carbamate derivative and its mechanism of action is thought to be related to its ability to increase the levels of dopamine, a neurotransmitter, in the brain. However, due to concerns about liver toxicity, pemoline was withdrawn from the market in many countries including the United States. It's important to note that Pemoline should only be used under the supervision of a physician and it's not commonly used or recommended anymore.

Microdialysis is a minimally invasive technique used in clinical and research settings to continuously monitor the concentration of various chemicals, such as neurotransmitters, drugs, or metabolites, in biological fluids (e.g., extracellular fluid of tissues, blood, or cerebrospinal fluid). This method involves inserting a small, flexible catheter with a semipermeable membrane into the region of interest. A physiological solution is continuously perfused through the catheter, allowing molecules to diffuse across the membrane based on their concentration gradient. The dialysate that exits the catheter is then collected and analyzed for target compounds using various analytical techniques (e.g., high-performance liquid chromatography, mass spectrometry).

In summary, microdialysis is a valuable tool for monitoring real-time changes in chemical concentrations within biological systems, enabling better understanding of physiological processes or pharmacokinetic properties of drugs.

Tyramine is not a medical condition but a naturally occurring compound called a biogenic amine, which is formed from the amino acid tyrosine during the fermentation or decay of certain foods. Medically, tyramine is significant because it can interact with certain medications, particularly monoamine oxidase inhibitors (MAOIs), used to treat depression and other conditions.

The interaction between tyramine and MAOIs can lead to a hypertensive crisis, a rapid and severe increase in blood pressure, which can be life-threatening if not treated promptly. Therefore, individuals taking MAOIs are often advised to follow a low-tyramine diet, avoiding foods high in tyramine, such as aged cheeses, cured meats, fermented foods, and some types of beer and wine.

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.

Catecholamines are a group of hormones and neurotransmitters that are derived from the amino acid tyrosine. The most well-known catecholamines are dopamine, norepinephrine (also known as noradrenaline), and epinephrine (also known as adrenaline). These hormones are produced by the adrenal glands and are released into the bloodstream in response to stress. They play important roles in the "fight or flight" response, increasing heart rate, blood pressure, and alertness. In addition to their role as hormones, catecholamines also function as neurotransmitters, transmitting signals in the nervous system. Disorders of catecholamine regulation can lead to a variety of medical conditions, including hypertension, mood disorders, and neurological disorders.

Neuroblastoma is defined as a type of cancer that develops from immature nerve cells found in the fetal or early postnatal period, called neuroblasts. It typically occurs in infants and young children, with around 90% of cases diagnosed before age five. The tumors often originate in the adrenal glands but can also arise in the neck, chest, abdomen, or spine. Neuroblastoma is characterized by its ability to spread (metastasize) to other parts of the body, including bones, bone marrow, lymph nodes, and skin. The severity and prognosis of neuroblastoma can vary widely, depending on factors such as the patient's age at diagnosis, stage of the disease, and specific genetic features of the tumor.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Probenecid is a medication that is primarily used to treat gout and hyperuricemia (high levels of uric acid in the blood). It works by decreasing the production of uric acid in the body and increasing its excretion through the kidneys.

In medical terms, probenecid is a uricosuric agent, which means it increases the urinary excretion of urate, the salt form of uric acid. It does this by inhibiting the reabsorption of urate in the proximal tubules of the kidneys, thereby promoting its elimination in the urine.

Probenecid is also used in conjunction with certain antibiotics, such as penicillin and cephalosporins, to increase their concentration in the body by reducing their excretion by the kidneys. This is known as probenecid-antibiotic interaction.

It's important to note that probenecid should be used under the supervision of a healthcare provider, and its use may be contraindicated in certain medical conditions or in combination with specific medications.

Chlorpromazine is a type of antipsychotic medication, also known as a phenothiazine. It works by blocking dopamine receptors in the brain, which helps to reduce the symptoms of psychosis such as hallucinations, delusions, and disordered thinking. Chlorpromazine is used to treat various mental health conditions including schizophrenia, bipolar disorder, and severe behavioral problems in children. It may also be used for the short-term management of severe anxiety or agitation, and to control nausea and vomiting.

Like all medications, chlorpromazine can have side effects, which can include drowsiness, dry mouth, blurred vision, constipation, weight gain, and sexual dysfunction. More serious side effects may include neurological symptoms such as tremors, rigidity, or abnormal movements, as well as cardiovascular problems such as low blood pressure or irregular heart rhythms. It is important for patients to be monitored closely by their healthcare provider while taking chlorpromazine, and to report any unusual symptoms or side effects promptly.

Benserazide is a type of medication called an inhibitor of peripheral aromatic amino acid decarboxylase. It is often used in combination with levodopa to treat Parkinson's disease. Benserazide works by preventing the conversion of levodopa to dopamine outside of the brain, which helps to reduce the side effects of levodopa and increase the amount of dopamine that reaches the brain. This can help to improve the symptoms of Parkinson's disease, such as stiffness, tremors, and difficulty with movement.

Benserazide is available in combination with levodopa under the brand name Madopar. It is taken orally, usually in the form of tablets. The specific dosage of benserazide will depend on the individual's needs and should be determined by a healthcare professional.

It is important to note that benserazide can interact with other medications, so it is important to inform your doctor about all the medications you are taking before starting treatment with benserazide. Additionally, benserazide may cause side effects, such as nausea, dizziness, and dry mouth. If you experience any severe or persistent side effects while taking benserazide, you should contact your healthcare provider.

Pargyline is an antihypertensive drug and a irreversible monoamine oxidase inhibitor (MAOI) of type B. It works by blocking the breakdown of certain chemicals in the brain, such as neurotransmitters, which can help improve mood and behavior in people with depression.

Pargyline is not commonly used as a first-line treatment for depression due to its potential for serious side effects, including interactions with certain foods and medications that can lead to dangerously high blood pressure. It is also associated with a risk of serotonin syndrome when taken with selective serotonin reuptake inhibitors (SSRIs) or other drugs that increase serotonin levels in the brain.

Pargyline is available only through a prescription and should be used under the close supervision of a healthcare provider.

Alpha-Methyltyrosine (α-MT) is a synthetic amino acid that acts as an inhibitor of the enzyme tyrosine hydroxylase. This enzyme is a rate-limiting step in the biosynthesis of catecholamines, including neurotransmitters such as dopamine and norepinephrine. By inhibiting tyrosine hydroxylase, α-MT reduces the synthesis of these catecholamines, which can lead to various effects on the nervous system.

In medical contexts, α-MT has been used in research settings to study the functions of catecholamines and their role in various physiological processes. It has also been investigated as a potential treatment for certain conditions, such as hypertension and anxiety disorders, although its clinical use is not widespread due to its side effects and limited efficacy.

It's important to note that α-MT should only be used under the supervision of a medical professional, as it can have significant effects on the nervous system and may interact with other medications or health conditions.

I'm sorry for any confusion, but "Methyltyrosines" is not a widely recognized medical term or concept in the field of medicine or biochemistry. It seems that there might be some misunderstanding or typo in your question.

If you are referring to "3-Methoxytyrosine" or "3-MT," it is a metabolite of dopamine, which is formed in the body by the enzyme catechol-O-methyltransferase (COMT). 3-MT can be measured in various biological samples, such as urine or plasma, to evaluate the activity of COMT and assess the exposure to drugs that inhibit this enzyme.

If you meant something else by "Methyltyrosines," please provide more context or clarify your question so I can give a more accurate answer.

Monoamine oxidase (MAO) is an enzyme found on the outer membrane of mitochondria in cells throughout the body, but primarily in the gastrointestinal tract, liver, and central nervous system. It plays a crucial role in the metabolism of neurotransmitters and dietary amines by catalyzing the oxidative deamination of monoamines. This enzyme exists in two forms: MAO-A and MAO-B, each with distinct substrate preferences and tissue distributions.

MAO-A preferentially metabolizes serotonin, norepinephrine, and dopamine, while MAO-B is mainly responsible for breaking down phenethylamines and benzylamines, as well as dopamine in some cases. Inhibition of these enzymes can lead to increased neurotransmitter levels in the synaptic cleft, which has implications for various psychiatric and neurological conditions, such as depression and Parkinson's disease. However, MAO inhibitors must be used with caution due to their potential to cause serious adverse effects, including hypertensive crises, when combined with certain foods or medications containing dietary amines or sympathomimetic agents.

Electrochemistry is a branch of chemistry that deals with the interconversion of electrical energy and chemical energy. It involves the study of chemical processes that cause electrons to move, resulting in the transfer of electrical charge, and the reverse processes by which electrical energy can be used to drive chemical reactions. This field encompasses various phenomena such as the generation of electricity from chemical sources (as in batteries), the electrolysis of substances, and corrosion. Electrochemical reactions are fundamental to many technologies, including energy storage and conversion, environmental protection, and medical diagnostics.

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that work by blocking the action of monoamine oxidase, an enzyme found in the brain and other organs of the body. This enzyme is responsible for breaking down certain neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are chemicals that transmit signals in the brain.

By inhibiting the action of monoamine oxidase, MAOIs increase the levels of these neurotransmitters in the brain, which can help to alleviate symptoms of depression and other mood disorders. However, MAOIs also affect other chemicals in the body, including tyramine, a substance found in some foods and beverages, as well as certain medications. As a result, MAOIs can have serious side effects and interactions with other substances, making them a less commonly prescribed class of antidepressants than other types of drugs.

MAOIs are typically used as a last resort when other treatments for depression have failed, due to their potential for dangerous interactions and side effects. They require careful monitoring and dosage adjustment by a healthcare provider, and patients must follow strict dietary restrictions while taking them.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

Dialysis is a medical treatment that is used to remove waste and excess fluid from the blood when the kidneys are no longer able to perform these functions effectively. This life-sustaining procedure uses a specialized machine, called a dialyzer or artificial kidney, to filter the blood outside of the body and return clean, chemically balanced blood back into the body.

There are two main types of dialysis: hemodialysis and peritoneal dialysis.

1. Hemodialysis: In this method, a patient's blood is passed through an external filter (dialyzer) that removes waste products, toxins, and excess fluids. The cleaned blood is then returned to the body with the help of a specialized machine. Hemodialysis typically requires access to a large vein, often created by a surgical procedure called an arteriovenous (AV) fistula or graft. Hemodialysis sessions usually last for about 3-5 hours and are performed three times a week in a clinical setting, such as a dialysis center or hospital.
2. Peritoneal Dialysis: This method uses the lining of the patient's own abdomen (peritoneum) as a natural filter to clean the blood. A sterile dialysate solution is introduced into the peritoneal cavity via a permanently implanted catheter. The solution absorbs waste products and excess fluids from the blood vessels lining the peritoneum through a process called diffusion. After a dwell time, usually several hours, the used dialysate is drained out and replaced with fresh dialysate. This process is known as an exchange and is typically repeated multiple times throughout the day or night, depending on the specific type of peritoneal dialysis (continuous ambulatory peritoneal dialysis or automated peritoneal dialysis).

Both methods have their advantages and disadvantages, and the choice between them depends on various factors, such as a patient's overall health, lifestyle, and personal preferences. Dialysis is a life-saving treatment for people with end-stage kidney disease or severe kidney dysfunction, allowing them to maintain their quality of life and extend their lifespan until a kidney transplant becomes available or their kidney function improves.

5-Hydroxytryptophan (5-HTP) is a chemical compound that is produced by the body as a precursor to serotonin, a neurotransmitter that helps regulate mood, appetite, sleep, and pain sensation. 5-HTP is not present in food but can be derived from the amino acid tryptophan, which is found in high-protein foods such as turkey, chicken, milk, and cheese.

5-HTP supplements are sometimes used to treat conditions related to low serotonin levels, including depression, anxiety, insomnia, migraines, and fibromyalgia. However, the effectiveness of 5-HTP for these conditions is not well established, and it can have side effects and interact with certain medications. Therefore, it's important to consult a healthcare provider before taking 5-HTP supplements.

Catechol-O-methyltransferase (COMT) is an enzyme that plays a role in the metabolism of catecholamines, which are neurotransmitters and hormones such as dopamine, norepinephrine, and epinephrine. COMT mediates the transfer of a methyl group from S-adenosylmethionine (SAM) to a catechol functional group in these molecules, resulting in the formation of methylated products that are subsequently excreted.

The methylation of catecholamines by COMT regulates their concentration and activity in the body, and genetic variations in the COMT gene can affect enzyme function and contribute to individual differences in the metabolism of these neurotransmitters. This has been implicated in various neurological and psychiatric conditions, including Parkinson's disease, schizophrenia, and attention deficit hyperactivity disorder (ADHD).

Neurotransmitter agents are substances that affect the synthesis, storage, release, uptake, degradation, or reuptake of neurotransmitters, which are chemical messengers that transmit signals across a chemical synapse from one neuron to another. These agents can be either agonists, which mimic the action of a neurotransmitter and bind to its receptor, or antagonists, which block the action of a neurotransmitter by binding to its receptor without activating it. They are used in medicine to treat various neurological and psychiatric disorders, such as depression, anxiety, and Parkinson's disease.

Tyrosine 3-Monooxygenase (also known as Tyrosinase or Tyrosine hydroxylase) is an enzyme that plays a crucial role in the synthesis of catecholamines, which are neurotransmitters and hormones in the body. This enzyme catalyzes the conversion of the amino acid L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by adding a hydroxyl group to the 3rd carbon atom of the tyrosine molecule.

The reaction is as follows:

L-Tyrosine + O2 + pterin (co-factor) -> L-DOPA + pterin (oxidized) + H2O

This enzyme requires molecular oxygen and a co-factor such as tetrahydrobiopterin to carry out the reaction. Tyrosine 3-Monooxygenase is found in various tissues, including the brain and adrenal glands, where it helps regulate the production of catecholamines like dopamine, norepinephrine, and epinephrine. Dysregulation of this enzyme has been implicated in several neurological disorders, such as Parkinson's disease.

Methyl-phenyl-tetrahydropyridine (MPTP) poisoning is a rare neurological disorder that occurs due to the accidental exposure or intentional intake of MPTP, a chemical compound that can cause permanent parkinsonian symptoms. MPTP is metabolized into MPP+, which selectively destroys dopaminergic neurons in the substantia nigra pars compacta region of the brain, leading to Parkinson's disease-like features such as rigidity, bradykinesia, resting tremors, and postural instability. MPTP poisoning can be a model for understanding Parkinson's disease pathophysiology and developing potential treatments.

The neostriatum is a component of the basal ganglia, a group of subcortical nuclei in the brain that are involved in motor control, procedural learning, and other cognitive functions. It is composed primarily of two types of neurons: medium spiny neurons and aspiny interneurons. The neostriatum receives input from various regions of the cerebral cortex and projects to other parts of the basal ganglia, forming an important part of the cortico-basal ganglia-thalamo-cortical loop.

In medical terminology, the neostriatum is often used interchangeably with the term "striatum," although some sources reserve the term "neostriatum" for the caudate nucleus and putamen specifically, while using "striatum" to refer to the entire structure including the ventral striatum (also known as the nucleus accumbens).

Damage to the neostriatum has been implicated in various neurological conditions, such as Huntington's disease and Parkinson's disease.

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.

Chromatography, gas (GC) is a type of chromatographic technique used to separate, identify, and analyze volatile compounds or vapors. In this method, the sample mixture is vaporized and carried through a column packed with a stationary phase by an inert gas (carrier gas). The components of the mixture get separated based on their partitioning between the mobile and stationary phases due to differences in their adsorption/desorption rates or solubility.

The separated components elute at different times, depending on their interaction with the stationary phase, which can be detected and quantified by various detection systems like flame ionization detector (FID), thermal conductivity detector (TCD), electron capture detector (ECD), or mass spectrometer (MS). Gas chromatography is widely used in fields such as chemistry, biochemistry, environmental science, forensics, and food analysis.

Parkinson's disease is a progressive neurodegenerative disorder that affects movement. It is characterized by the death of dopamine-producing cells in the brain, specifically in an area called the substantia nigra. The loss of these cells leads to a decrease in dopamine levels, which results in the motor symptoms associated with Parkinson's disease. These symptoms can include tremors at rest, stiffness or rigidity of the limbs and trunk, bradykinesia (slowness of movement), and postural instability (impaired balance and coordination). In addition to these motor symptoms, non-motor symptoms such as cognitive impairment, depression, anxiety, and sleep disturbances are also common in people with Parkinson's disease. The exact cause of Parkinson's disease is unknown, but it is thought to be a combination of genetic and environmental factors. There is currently no cure for Parkinson's disease, but medications and therapies can help manage the symptoms and improve quality of life.

Dopamine agents are medications that act on dopamine receptors in the brain. Dopamine is a neurotransmitter, a chemical messenger that transmits signals in the brain and other areas of the body. It plays important roles in many functions, including movement, motivation, emotion, and cognition.

Dopamine agents can be classified into several categories based on their mechanism of action:

1. Dopamine agonists: These medications bind to dopamine receptors and mimic the effects of dopamine. They are used to treat conditions such as Parkinson's disease, restless legs syndrome, and certain types of dopamine-responsive dystonia. Examples include pramipexole, ropinirole, and rotigotine.
2. Dopamine precursors: These medications provide the building blocks for the body to produce dopamine. Levodopa is a commonly used dopamine precursor that is converted to dopamine in the brain. It is often used in combination with carbidopa, which helps to prevent levodopa from being broken down before it reaches the brain.
3. Dopamine antagonists: These medications block the action of dopamine at its receptors. They are used to treat conditions such as schizophrenia and certain types of nausea and vomiting. Examples include haloperidol, risperidone, and metoclopramide.
4. Dopamine reuptake inhibitors: These medications increase the amount of dopamine available in the synapse (the space between two neurons) by preventing its reuptake into the presynaptic neuron. They are used to treat conditions such as attention deficit hyperactivity disorder (ADHD) and depression. Examples include bupropion and nomifensine.
5. Dopamine release inhibitors: These medications prevent the release of dopamine from presynaptic neurons. They are used to treat conditions such as Tourette's syndrome and certain types of chronic pain. Examples include tetrabenazine and deutetrabenazine.

It is important to note that dopamine agents can have significant side effects, including addiction, movement disorders, and psychiatric symptoms. Therefore, they should be used under the close supervision of a healthcare provider.

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Haubrich, DR; Goldberg, ME (1975). "Homovanillic acid concentration in the rat brain: Effect of a choline acetyltransferase ...
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This neurotoxin reduced levels of dopamine, noradrenaline, and homovanillic acid, a metabolite of dopamine, and is known to ...
In 1981, Japan started a program of screening for neuroblastoma by measuring homovanillic acid and vanilmandelic acid in urine ...
... to form homovanillic acid (HVA), which is then typically excreted in the urine. Originally thought to be physiologically ...
SLC6A3-related DTDS display raised homovanillic acid (HVA) levels with normal 5-hydroxyindoleacetic acid (5-HIAA, a serotonin ... Various other symptoms present less commonly (30-79%), including bradykinesia (slowness of movement), acid reflux, muscular ...
This analysis reveals decreased concentrations of homovanillic acid (HVA), 5-hydroxyindolacetic acid (HIAA), and elevated ... BH4 is involved in the processing of amino acids and the production of neurotransmitters, specifically that of dopamine and ...
Patients typically have normal levels of 5-hydroxyindolacetic acid (5HIAA), low levels of homovanillic acid (HVA) and 3-methoxy ...
... and homovanillic acid, and may produce severe watery diarrhea through production of vasoactive intestinal peptide. Treatment of ... Neuroblastic tumors often produce elevated levels of catecholamine hormone metabolites, such as vanillylmandelic acid (VMA) ... Nucleic Acids Research. 39 (16): 7223-7233. doi:10.1093/nar/gkr254. PMC 3167594. PMID 21609964. Valadi H, Ekström K, Bossios A ...
... a phenolic compound Flopropione Homovanillic acid m-Hydroxyphenylhydracrylic acid Methylenomycin A Syringaldehyde Veratric acid ... 5-Dihydroxyphenylpropionoic acid, a metabolite of alkylresorcinols Dihydrocaffeic acid, a phenolic compound Ethyl ... a benzoic acid derivative This set index page lists chemical structure articles associated with the same molecular formula. If ...
... a Dutch educational institution Homovanillic acid, a major catecholamine metabolite Husqvarna Motorcycles, now a subsidiary of ...
... and decreases plasma and urinary dopamine and homovanillic acid. Elimination half-life of levodopa in the presence of carbidopa ... Karady S, Ly MG, Pines SH, Sletzinger M (1971). "Synthesis of D- and L-α-(3,4-dihydroxybenzyl)-α-hydrazinopropionic acid via ... Carbidopa is also used in combination with 5-HTP, a naturally occurring amino acid which is a precursor to the neurotransmitter ... GB 940596, Chemerda JM, Sletzinger M, Bollinger FW, "α-hydrazino acids", published 1963-10-30, assigned to Merck & Co. Inc. DE ...
Dopamine to dihydroxyphenylacetic acid 3-Methoxytyramine to homovanillic acid Because of the vital role that MAOs play in the ... 4-Dihydroxymandelic acid Metanephrine or normetanephrine to vanillylmandelic acid (VMA) ...
Furthermore, decreased levels of homovanillic acid, altered response to dextroamphetamine, responses of depressive symptoms to ... There is insufficient high quality evidence to suggest omega-3 fatty acids are effective in depression. There is limited ... November 2021). "Omega-3 fatty acids for depression in adults". Cochrane Database Syst Rev. 2021 (11): CD004692. doi:10.1002/ ...
... homovanillic acid), norepinephrine (3-methoxy-4-hydroxyphenylglycol), and serotonin (5-hydroxyindoleacetic acid). Although less ...
Specific reactions catalyzed by COMT include: Dopamine → 3-methoxytyramine DOPAC → HVA (homovanillic acid) Norepinephrine → ... 4-Dihydroxymandelic acid (DOMA) → vanillylmandelic acid (VMA) In the brain, COMT-dependent dopamine degradation is of ...
Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. In ... Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and ... Homovanillyl alcohol Lambert, G.W.; Eisenhofer, G.; Jennings, G.L.; Esler, M.D. (1993). "Regional homovanillic acid production ... "The sex difference of plasma homovanillic acid is unaffected by cross-sex hormone administration in transgender people". J ...
Homovanillic acid (tms); Benzeneacetic acid, 4-hydroxy-3-methoxy, bis-TMS; Homovanillic acid, bis-TMS; Homovanillic acid, di- ... TMS; Phenylacetic acid, 3-methoxy-4-trimethylsilyloxy-, trimethylsilyl ester; Homovalillic acid, bis-TMS; Homovanilic acid, TMS ... Homovanillic Acid, 2TMS derivative. *Formula: C15H26O4Si2 ... Wurth, C.; Kumps, A.; Mardens, Y., Urinary organic acids: ... Richards, M.; Wong, Y.S.; Tan, W.C.; Tan, I.K.; Ng, T.L., Profiling urinary organic acids for the diagnosis of inborn errors of ...
Benzeneacetic acid, 4-hydroxy-3-methoxy-(CAS). EINECS:206-176-7. HVA. Homovanillic acid [Wiki]. Vanilacetic acid. ... Categories: Phenolic acid PubChem CID: 1738 , NSC 16682 , ChemSpider ID: 1675 , CHEBI:545959 , CHEMBL1562 , MolPort-000-156-338 ... Homovanillic acid Molecular formula: C9H10O4 CAS# 306-08-1 ... Homovanillic acid. Find chemicals by name or formulas. ...
50 mL (10 mL min.) aliquot of random Urine. Add 50% HCl drop by drop to bring the pH between 1â€"2. Do not use concentrated HCl. Ship refrigerated or frozen. Patient should strictly avoid L-Dopa at least 72 hours before and during collection.. ...
Dopamine homovanillic acid. In 1986, Stahl et al measured the dopamine metabolite homovanillic acid (HVA) in cerebrospinal ... Cerebrospinal fluid homovanillic acid is reduced in untreated Huntingtons disease. Clin Neuropharmacol. 1995 Feb. 18(1):58-63 ...
2-Methylglutaconic Acid, 2-Octenedioic acid, 2-Octenoic Acid, 2-OH-3ME-Valeric, 2-Oxo-3-methylvaleric, 2-OXO-Butyric Acid, 2- ... 30H-ISOVALERIC ACID, 3OH-2-Methylvaleric Acid, 3OH-Dodecanedioic Acid, 3OH-Dodecanoic Acid, 4 HYDROXYCYCLOHEX- ANEACETIC, 4- ... HOMOVANILLIC ACID, Isobutyrylglycine, Isocitric, Isovaleryglycine, Lactic, Lactic Acid, Malic, Malonic, Methylcitric, ... Navigate to Organic Acids, Comprehensive, Quantitative Popular search. 2-Decenedioic Acid, 2-ET-3-OH-Propionic, 2-Hydroxyadipic ...
Homovanilic Acid; HOC6H3(OCH3)CH2COOH; 3-Methoxy-4-hydroxyphenyl Acetic Acid; 4-Hydroxy-3-Methoxy-Benzeneacetic Acid; 4-Hydroxy ... Homovanillic Acid (HVA) Polyclonal Antibody, Cat#CAU23138. Rating Required Select Rating. 1 star (worst). 2 stars. 3 stars ( ...
This increases urinary excretion of your primary dopamine metabolite homovanillic acid and decreases urinary excretion of NE ... and its significant metabolite vanillylmandelic acid.[6] In addition, sideeffects of DSF for instance fatigue, tremor, lowered ... E.[10] This increases urinary excretion of your primary dopamine metabolite homovanillic acid and decreases urinary. Posted on ... E.[10] This increases urinary excretion of your primary dopamine metabolite homovanillic acid and decreases urinary excretion ...
Plasma homovanillic acid, serum anti-D1 and anti-D2 receptor activity, and psychopathology in chronic schizophrenia. ... Dive into the research topics of Plasma homovanillic acid, serum anti-D1 and anti-D2 receptor activity, and psychopathology in ...
Gas Chromatographic Estimation of Homovanillic Acid in Serum of Normals and Psychotic Patients. ... The Reliability of a Mechanized Procedure (Perkin-Elmer C4) for the Enzymatic Determination of Uric Acid According to Kageyama ... A New Enzymatic Method for the Determination of Free and Conjugated Glucuronic Acid. ...
... homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens of the rat, prior, during, and after ... In vivo microdialysis with HPLC-ED was used to measure dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid ... HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens of the rat, prior, during, and after 15-min periods of ...
Determination of homovanillic acid and vanillylmandelic acid in urine of autistic children by gas chromatography/mass ...
5-Hydroxyindoleacetic Acid (5-HIAA). *17-Ketosteroid. *Catecholamine Fractionated. *Homovanillic Acid (HVA) ...
3-methoxy-4-hydroxy-phenylacetic acid;. Homovanilic;. Homovanillic acid;. CR;. Interpretation;. Interp;. Impression;. ...
The test is called : Homovanillic Acid (HVA) 24 Hour, Urine Test.. The test can be useful in screening children for ...
Cellular, molecular and biochemical studies in human subjects report changes affecting the gamma-amino butyric acid (GABA) ... Kasa K, Otsuki S, Yamamoto M, Sato M, Kuroda H, Ogawa N. Cerebrospinal fluid gamma-aminobutyric acid and homovanillic acid in ... Reduced gamma-aminobutyric acid in occipital and anterior cingulate cortices in primary insomnia: a link to major depressive ... Petty F, Kramer GL, Gullion CM, John Rush A. Low plasma γ-aminobutyric acid levels in male patients with depression. Biol ...
Glutamic acid decarboxylase (GAD) enzymes synthesize GABA from glutamate, and, thus, are reasonable candidate susceptibility ... Abnormalities in the gamma-aminobutyric acid (GABA) neurotransmitter system have been noted in subjects with mood and anxiety ... Kasa K, Otsuki S, Yamamoto M, Sato M, Kuroda H, Ogawa N . Cerebrospinal fluid gamma-aminobutyric acid and homovanillic acid in ... Cleft palate and decreased brain gamma-aminobutyric acid in mice lacking the 67-kDa isoform of glutamic acid decarboxylase. ...
5-hydroxyindoleacetic acid and homovanillic acid in brain tissue from an autopsy material. Acta Psychiatr. Scand. 50, 496-507. ...
tetrahydrobiopterin - hyperphenylalaninemia - dihydropteridine reductase - GTP cyclohydrolase I - homovanillic acid - pterin-4 ... 23 Hyland K. Inherited disorders affecting dopamine and serotonin: critical neurotransmitters derived from aromatic amino acids ... of folinic acid supplements and pramipexole. Dopamine agonists can improve L-dopa therapy, making treatment easier, relieving ...
Levels of urinary homovanillic acid and vanillylmandelic acid were within normal limits. ... and uric acid were all within normal limits. ...
Cerebrospinal fluid homovanillic acid is reduced in untreated Huntingtons disease. Clin Neuropharmacol. 1995 Feb. 18(1):58-63 ... Neurochemically, levels of transmitter substances (eg, GABA and its synthetic enzyme glutamic acid decarboxylase) are markedly ...
Serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic ... acid (HVA) were analyzed via HPLC. Although MDMA-treated monkeys tended to have lower 5-HT concentrations in the frontal cortex ...
A 3-O-methyl ETHER of (3,4-dihydroxyphenyl)acetic acid.. Terms. Homovanillic Acid Preferred Term Term UI T020286. Date01/01/ ... Homovanillic Acid Preferred Concept UI. M0010524. Registry Number. X77S6GMS36. Related Numbers. 306-08-1. Scope Note. ... Carboxylic Acids [D02.241] * Acids, Carbocyclic [D02.241.223] * Phenylacetates [D02.241.223.601] * Cyclopentolate [D02.241. ... A 3-O-methyl ETHER of (3,4-dihydroxyphenyl)acetic acid.. Entry Term(s). 3-Methoxy-4-Hydroxyphenylacetic Acid 4-Hydroxy-3- ...
Recently, the increases in l-[β-11C]DOPA metabolites, [11C]3,4-dihydroxyphenylacetic acid ([11C]DOPAC) and [11C]homovanillic ... NAA concentration was measured by HPLC (L-8500 amino acid analyzer system, Hitachi). The amino acids are phenylalanine, ... A venous blood sample was taken at the beginning of l-[β-11C]DOPA PET scanning for measurement of natural neutral amino acid ( ... 1972) Occurrence and distribution of aromatic L-amino acid (L-DOPA) decarboxylase in the human brain. J Neurochem 19:1549-1559. ...
4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of [3H]mazindol-labeled norepinephrine or dopamine uptake ... Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid were observed in cerebral cortex, hippocampus, ...
Plants exhibit increased synthesis of polyphenols such as phenolic acids and flavonoids under abiotic stress conditions, which ... caffeic acid, coumaric acid, cinnamic acid, gallic acid, homovanillic acid, ferulic acid, salicylic acid and vanillic acid.. [ ... caffeic acid, coumaric acid, cinnamic acid, gallic acid, homovanillic acid, ferulic acid, salicylic acid, and vanillic acid [76 ... tartaric acid, citric acid, malonic acid, malic acid, succinic acid, oxaloacetic acid, oxalic acid, and methyl malonic acid) in ...
Some studies have demonstrated reduction in dopamine levels and in its main metabolite, homovanillic acid in the cerebrospinal ... Perchloric acid (HClO4), Na2S2)2, EDTA-disodium salt (titriplex III) citric acid, orthophosphoric acid, hydrochloric acid, ... ascorbic acid (20 ug.ul-1 concentration) was infused in a speed of 0.1 l/min (around 2 minutes long). Ascorbic acid was used as ... In the first experiment, 62% (15/24) of 6-OHDA pre-treated rats and 45% (11/24) of those receiving ascorbic acid as control ...
  • Levels of urinary homovanillic acid and vanillylmandelic acid were within normal limits. (contemporarypediatrics.com)
  • Additionally, urine catecholamine metabolite screening (Vanillylmandelic acid and homovanillic acid, VMA/HVA) is sometimes completed because excess production of these catecholamines and their metabolites is common in neuroblastoma. (chop.edu)
  • Dopamine becomes 3-methoxytyramine (3-MT) and homovanillic acid (HVA), noradrenaline breaks down into normetadrenaline and vanillylmandelic acid (VMA) (also known as HMMA), and adrenaline becomes metadrenaline and VMA. (labtestsonline.org.uk)
  • In 1986, Stahl et al measured the dopamine metabolite homovanillic acid (HVA) in cerebrospinal fluid (CSF) before and after probenecid administration in healthy controls and in patients with HD. (medscape.com)
  • Homovanillate (aka Homovanillic Acid) is a dopamine metabolite. (healthmatters.io)
  • Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and catechol-O-methyltransferase on dopamine. (wikipedia.org)
  • In vivo microdialysis with HPLC-ED was used to measure dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens of the rat, prior, during, and after 15-min periods of electrical brain stimulation at sites in the ventral tegmental area (VTA) that supported intracranial self-stimulation (ICSS). (nih.gov)
  • Serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) were analyzed via HPLC. (erowid.org)
  • DESIGN/METHODS: Putamen and caudate DA, homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), and 3-methoxytyramine (3MT) levels were analyzed by high pressure liquid chromatography with electrochemical detection in 182 HAAS brains. (cdc.gov)
  • Following intraperitoneal administration of the non-competitive N-methyl-D-aspartate (NMDA) antagonist dizocilpine (MK-801), levels of the dopamine (DA) metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) increased in mouse striatum and limbic forebrain. (eurekamag.com)
  • Acute clozapine challenge (5-40 mg/kg i.p) produced dose-dependent increased extracellular levels of DA and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in the medial prefrontal cortex of awake, free-moving rats as measured by in vivo brain microdialysis. (elsevierpure.com)
  • However, DA metabolites, HVA (homovanillic acid) and DOPAC (3,4-dihydroxyphenylacetic acid) are not responsible for such protection. (uchile.cl)
  • Carbidopa reduces the amount of levodopa required to produce a given response by about 75% and, when administered with levodopa, increases both plasma levels and the plasma half-life of levodopa, and decreases plasma and urinary dopamine and homovanillic acid. (nih.gov)
  • A 3-O-methyl ETHER of (3,4-dihydroxyphenyl)acetic acid. (nih.gov)
  • "Improvements in FMD at 6 h after consumption were correlated with the appearance of metabolites derived from anthocyanin and chlorogenic acid, notably hippuric, hydroxyhippuric acid, and homovanillic acid," ​they added. (nutraingredients.com)
  • 10:27 The NutraEval measures organic acids and amino acids, which gives us a perspective on the metabolome, which are the various metabolites that provide a functional readout of the activity within the cells and this is based on medical biochemistry. (drweitz.com)
  • In contrast, neither MDMA nor MDA caused any widespread or long-term changes in the content of the catecholaminergic markers (i.e., norepinephrine, dopamine, 3,4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of [3H]mazindol-labeled norepinephrine or dopamine uptake sites in the brain regions examined. (erowid.org)
  • The NutraEval is measuring things both intracellular , like red blood cell magnesium, and extracellular , like plasma amino acids, plasma copper and zinc, and serum CoQ10. (drweitz.com)
  • and platelet count, 9210 3 /?L. Levels of serum electrolytes, liver enzymes, lactate dehydrogenase, and uric acid were all within normal limits. (contemporarypediatrics.com)
  • Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. (wikipedia.org)
  • 6:15 The NutraEval includes organic acids, oxidative stress markers and antioxidants, amino acids, essential fatty acids, nutrient and toxic elements and you have the opportunity to add on vitamin D and genomic SNPs. (drweitz.com)
  • Cyclic GMP-AMP (cGAMP) synthase (cGAS), a sensor of cytosolic DNA, recognizes cytoplasmic nucleic acids to activate the innate immune responses via generation of the second messenger cGAMP and subsequent activation of the stimulator of interferon genes (STING). (bvsalud.org)
  • The hnRNP proteins have distinct nucleic acid binding properties. (antibodies-online.com)
  • Abnormalities in the gamma-aminobutyric acid (GABA) neurotransmitter system have been noted in subjects with mood and anxiety disorders. (nature.com)
  • Cellular, molecular and biochemical studies in human subjects report changes affecting the gamma-amino butyric acid (GABA) system, specifically somatostatin-expressing (SST+) GABAergic interneurons, across brain disorders and during aging. (nature.com)
  • Carbidopa, an inhibitor of aromatic amino acid decarboxylation, is a white, crystalline compound, slightly soluble in water, with a molecular weight of 244.3. (nih.gov)
  • It is designated chemically as (-)-L-α-amino-β-(3,4-dihydroxybenzene) propanoic acid. (nih.gov)
  • Since levodopa competes with certain amino acids for transport across the gut wall, the absorption of levodopa may be impaired in some patients on a high protein diet. (nih.gov)
  • In the first experiment, 62% (15/24) of 6-OHDA pre-treated rats and 45% (11/24) of those receiving ascorbic acid as control solution progressed to motor limbic seizures evolving to SE, after the administration of pilocarpine. (scielo.br)
  • We found that resveratrol (10 μM) and ascorbic acid (200 μM) protected MeHg-induced cell death in primary cultures of cortical neurons. (uchile.cl)
  • They help transmit nerve impulses in the brain, increase glucose and fatty acid release for energy, dilate small air passages in the lungs called bronchioles, and dilate the pupils. (labtestsonline.org.uk)
  • This includes the fatty acid pathway, the beta oxidation pathway, which is how we move long chain fatty acids into the micochondria and if that pathway is inhibited, then we might see high levels of adipic and suberic acid and this often indicates an unmet need for magnesium or B2 or L-carnitine. (drweitz.com)
  • 25:08 Organic acids are on pages 7-9 and these are byproducts in a number of different body systems. (drweitz.com)
  • Fee C, Banasr M, Sibille E. Somatostatin-positive gamma-aminobutyric acid interneuron deficits in depression: cortical microcircuit and therapeutic perspectives. (nature.com)
  • Glutamic acid decarboxylase (GAD) enzymes synthesize GABA from glutamate, and, thus, are reasonable candidate susceptibility genes for these conditions. (nature.com)
  • At 1-2 hours after consumption of the blueberry polyphenols, the researchers found that ferulic acid, isoferulic acid, vanillic acid, 2-hydroxybenzoic acid, benzoic acid, and caffeic acid were significantly increased. (nutraingredients.com)
  • 23:20 If conventional MDs are skeptical of the NutraEval, you can point out that it includes many markers that are very well represented in the published literature, including methylmalonic acid, the omega-3 index, RBC magnesium, CoQ10, and glutathione. (drweitz.com)
  • The gold standard treatment of severe disorders of BH4 metabolism is based on replacement therapy with BH4, 5-hydroxytryptophan, L-dopa, and carbidopa, with the addition, in certain cases, of folinic acid supplements and pramipexole. (thieme-connect.de)
  • And there are heavy metals and toxins that can inhibit these metabolic pathways, like the Kreb's Citric Acid Cycle, and some of these toxins are measured on the NutrEval. (drweitz.com)
  • In 1986, Stahl et al measured the dopamine metabolite homovanillic acid (HVA) in cerebrospinal fluid (CSF) before and after probenecid administration in healthy controls and in patients with HD. (medscape.com)
  • This article presents new evidence that cerebrospinal fluid levels of the dopamine metabolite homovanillic acid are related to the severity of psychosis in schizophrenia. (elsevierpure.com)
  • These results support the concept that homovanillic acid levels in cerebrospinal fluid vary as a function of psychosis rather than being related to the diagnosis of schizophrenia per se. (elsevierpure.com)
  • RTTRD scores were correlated with age, ability to walk and speak, mutation type, and, in a small subgroup (n=9), cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole-acetic acid levels. (omeka.net)
  • D-amino acid oxidase activator gene (DAOA) variation affects cerebrospinal fluid homovanillic acid concentrations in healthy Caucasians. (cdc.gov)
  • Furthermore, dopamine turnover did not appear to be affected by the supplementation, as [homovanillic acid] HVA levels in urine were not affected. (fabresearch.org)
  • Increased urine homovanillic acid. (librepathology.org)
  • The concentrations of serum homovanillic acid (HVA), luteinizing liormone (LH), follicle-stimulating hormone (FSH) and testosterone (T) were examined in 20 male schizophrenic patients not taking neuroleptic drugs, 44 treated with neuroleptic drugs, and 15 male healthy control subjects. (uhi.ac.uk)
  • We included therapy-refractory OCD patients treated with DBS (41 year) and performed a baseline assessment of symptoms, as well as plasma concentrations of thyroid-stimulating hormone (TSH), prolactin, growth hormone, copeptin and homovanillic acid. (mssm.edu)
  • Dopaminergic neurones (concentrations of dopamine, dihydroxyphenylacetic acid and homovanillic acid) were not deficient but some markers of the other neurones were affected. (ox.ac.uk)
  • Summary Homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan (TRP) were measured in the CSF obtained from the basal cistern of 20 patients, who had undergone surgical obliteration of bleeding aneurysms within 3 days after subarachnoid haemorrhage (SAH). (zib.de)
  • Respectively the concentration of homovanillic acid (nvg) and 5-hydroxyindoleacetic acid (5-HIAA) was measured with or without probenecid (Olsson and Roos 1968, Van Praag et al 1970, Korf 1971). (dokumen.tips)
  • In Alzheimer subjects, a significant relationship (inverse) was found between 5-hydroxyindoleacetic acid concentration and the number of neurofibrillary tangles. (ox.ac.uk)
  • A higher than normal amount of the substances homovanillic acid (HMA) and vanillyl mandelic acid (VMA) may be a sign of neuroblastoma . (cookchildrens.org)
  • Tyrosine hydroxylase converts tyrosine to 3,4-dihydroxyphenylalanine (DOPA), which is converted to dopamine under the effect of aromatic l-amino acid decarboxylase, then dopamine β-hydroxylase converts dopamine to norepinephrine and phenylethanolamine N -methyltransferase converts norepinephrine to epinephrine. (medscape.com)
  • Williams CM, Greer M. Homovanillic acid and vanilmandelic acid in diagnosis of neuroblastoma. (edu.pk)
  • A 3-O-methyl ETHER of (3,4-dihydroxyphenyl)acetic acid. (nih.gov)
  • 2. Add 25 mL of 50% acetic acid as preservative at start of collection. (testcatalog.org)
  • Use 15 mL of 50% acetic acid for children less than 5 years old. (testcatalog.org)
  • Effects of oral L-tyrosine administration on CSF tyrosine and homovanillic acid levels in patients with Parkinson's disease. (wehaveparkinsons.com)
  • Carbidopa, an inhibitor of aromatic amino acid decarboxylation, is a white, crystalline compound, slightly soluble in water, with a molecular weight of 244.3. (nih.gov)
  • Its ability to increase the concentration of rat brain homovanillic acid (HVA) and the resulting time course for HVA were similar to the actions of clozapine. (duke.edu)
  • Probenecid impedes the egress of HVA and 5-HIAA OUt Off the CSF to the blood, what results in increase of these acids, giving an impression of cerebral the turnover of the original amines dopamine and serotonin. (dokumen.tips)
  • Tauroursodeoxycholic acid prevents MPTP-induced dopaminergic cell death in a mouse model of Parkinson's disease. (wehaveparkinsons.com)
  • Correlations among CSF homovanillic acid (HVA) values and other biochemical, clinical, neuroradiological, and electrophysiological parameters were analysed. (nih.gov)
  • Soluble salts of weak acids (e.g., carbonates, acetates, sulfides, and cyanides) do not exist in aqueous solution or in water, since they undergo complete hydrolysis, resulting in the precipitation of aluminum hydroxide [Al(OH)3]. (nih.gov)
  • We evaluated on a common and validated in vitro system the selectivity of 4-pyridoxic acid (PDA), homovanillic acid (HVA), glycochenodeoxycholate-3-sulphate (GCDCA-S) and taurine towards different renal transporters, including multidrug resistance-associated protein, and assessed the in vivo biomarker sensitivity towards the strong organic anion transporter (OAT) inhibitor probenecid at 500 mg every 6 h to reach close to complete OAT inhibition. (manchester.ac.uk)
  • There are of course three more ingredients in Restore Gold™, each added due to their positive support in Parkinson's research, Grape Seed Extract, Acetyl L-Carnitine, and Alpha Lipoic Acid (ALA) are also included at specific dosages. (wehaveparkinsons.com)
  • Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. (wikipedia.org)
  • As perhaps the most important ingredient, TUDCA (Tauroursodeoxycholic Acid) has been has been added to Restore Gold™ capsules due to the research suggesting it can actually restore mitochondrial function. (wehaveparkinsons.com)