Dopamine 3-0-sulfate

Studies on the fate of dopamine 4-sulfate (9.88) will serve to illustrate the reaction of deconjugation mentioned above. With this substrate, arylsulfatase activity in the dog was found to be highest in the kidney and liver, low in the intestine and heart, and almost nil in the brain and skeletal muscle [171]. Since this conjugate exists in high amounts in the plasma of humans, monkeys and dogs, the possibility was raised that it might be looked upon as a precursor or reservoir of free dopamine. 

Although the kidneys represent the major source of urinary free dopamine, this source does not account for the larger amounts of excreted dopamine metabolites, such as HVA and dopamine sulfate. Findings of large arterial-to-portal venous increases in plasma concentrations of dopamine and its metabolites have indicated that substantial amounts of dopamine are produced and metabolized in the GI tract and otlier mesenteric organs. ... 

Goldstein DS, Swoboda KJ, Miles JM, Coppack SW, Aneman A, Holmes C, et al. Sources and physiological significance of plasma dopamine sulfate. J Clin Endocrinol Metab 1999 84 2523-31. 

Zhigaltev FV, Kaplun AP, Kucheryanu VG, et al. Liposomes containing dopamine entrapped in response to transmembrane ammonium sulfate gradient as carrier system for Dopamine delivery into the brain of Parkinsonian mice. J Liposome Res 2001 11 55-71. 

Tyrosine (Tyr or Y) (4-hydroxyphenylalanine ((5)-2-amino-3-(4-hydroxyphenyl)-propanoic acid)) is a polar, neutral, aromatic amino acid with the formula H00CCH(NH2)CH2C6H50H and is the precursor of thyroxin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and the pigment melanin. Being the precursor amino acid for the thyroid gland hormone thyroxin, a defect in this may result in hypothyroidism. Tyr is extremely soluble in water, a property that has proven useful in isolating this amino acid from protein hydrolysates. The occurrence of tyrosine- 0-sulfate as a constituent of human urine and fibrinogen has been reported. ... 

Sulfotransferases (SULTs) are important for the metabolism of a number of drugs, neurotransmitters, and hormones, especially the steroid hormones. The cosubstrate for these reactions is 3 -phosphoadenosine 5 -phosphosulfate (PAPS) (Fig. 4.1). Like the aforementioned enzymes, sulfate conjugation typically renders the compound inactive and more water soluble. However, this process can also result in the activation of certain compounds, such as the antihypertensive minoxidil and several of the steroid hormones. Seven SULT isoforms identified in humans, including SULTs lAl to 1A3, possess activity toward phenolic substrates such as dopamine, estradiol, and acetaminophen. SULTIBI possesses activity toward such endogenous substrates as dopamine and triiodothyronine. SULTIEI has substantial activity toward steroid hormones, especially estradiol and dehydroepiandrosterone, and toward the anti-... 

Invernizzi R, Pozzi L, Vallebuona F, et al Effect of amineptine on regional extracellular concentrations of dopamine and noradrenaline in the rat brain. J Pharmacol Exp Ther 262 769-774, 1992b Irwin RP, Magarakis NJ, Rogawski MA, et al Pregnenolone sulfate augments NMDA receptor mediated increases in intracellular Ca in cultured rat hippocampal neurons. Neurosci Lett 141 30-34, 1992... 

Although quercetin may stimulate UGT, it inhibits human hepatic sulfation of resveratrol, acetaminophen, dopamine, (-)-salbutamol, minoxidil, and paracetamol in vitro.69,98-101 This inhibition may be chemopreventive, as activation of some promutagens occurs via SULT reactions.68 However, SULT inhibition may also lead to the accumulation of some xenobiotics and possible toxicity. The magnitude of inhibition by quercetin of SULT appears dependent on the isoform because SULT1A3 is less affected than other isoforms, suggesting a tissue-dependent effect of quercetin.69... 

Dopamine is degraded by alkaline preparation and is incompatible with sodium bicarbonate solutions, furosemide, ampicillin, amphotericin, gentamicin sulfate, cephalothin sodium, oxacillin sodium, and thiopentone sodium. Percussion or excessive heat may cause an explosion with undiluted erythrityl tetranitrate. Care must be exercised to avoid contact with skin, eyes, and mucous membranes when handling ethacrynic acid. Sodium ethacrynate solutions are incompatible and less stable at very high pH, below pH 5, and at higher temperatures. 

Risperdal Risperidone 0.25, 0.5, 1, 2, 3, 4 mg Tablet Schizophrenia A selective monoaminergic antagonist (5HT2, dopamine type 2 (D2), al and a2 adrenergic, and HI histaminergic receptors Colloidal silicon dioxide, hypromellose, lactose, magnesium stearate, MCC, propylene glycol, sodium lauryl sulfate, corn starch Janssen Pharmaceuticals... 

SULT 1B1 functions in the sulfation of diverse endogenous substrates include cholesterol, dehydroepiandrosterone (DHEA), thyroid hormone, and dopamine. The enzyme also contributes to the metabolism of phenolic xenobiotics such as those containing 2-naphthol. It is highly expressed in the liver, colon, small intestine, and blood leukocytes. 

Zhigaltsev, I. V., Kaplun, A. P, Kucheryanu, V. G., Kryzhanovsky, G. N., Kolomeichuk, S. N., Shvets, V. I., and Yurasov, V. V. (2001), Liposomes containing dopamine entrapped in response to transmembrane ammonium sulfate gradient as carrier system for dopamine delivery into the brain of parkinsonian mice, J. Liposome Res., 11,55-71. 

Figure 9,19 Chromatograms of the cosubstrate (PAPS) and products of liver phenol sulfotransferase activity. Upper tracing a, PAPS, b, sulfate-conjugated dopamine. Middle tracing a, PAPS, b, sufate-conjugated Dopac. Lower tracing a, PAPS, b, sulfate-conjugated phenol. The retention time for sulfate-conjugated dopamine, Dopac, and phenol was 4.5, 6.8, and 7.0 minutes, respectively. (From Sim and Hsu, 1990.)...

Phenolsulfotransferase catalyzes the transfer of active sulfate from 3 -phosphoadensine 5 -phosphosulfate to various phenols and catechols. Honkasalo and Nissinen (1988) developed an assay that is suitable for measuring both the thermolabile (TL) and thermostable (TS) isoforms of phenol sulfotransferase. Both are active toward phenols, while the TL form also conjugates catechols including dopamine. 

Monoamine oxidase inhibitors (MAOI) Neurotransmitters norepinephrine, dopamine, epinephrine, and serotonin are inactive by the enzyme monoamine oxidase. MAOI inhibits monoamine oxidase, resulting in a rise in the levels of these neurotransmitters. MAOI are isocarboxazid (Marplan), phenelzine sulfate (Nardil), and tranylcypromine sulfate (Parnate). 

At least eighteen phenylethylamines have been examined by x-ray crystallography. Among these are phenylethylamine hydrochloride (3 ), ephedrine hydrochloride (31), ephedrine monohydrogen phosphate monohydrate (32), ephedrine dihydrogen phosphate (33), dopamine hydrochloride (34), 5-hydroxydopamine hydrochloride (35), 6-hydroxydopamine hydrochloride (36), epinephrine hydrogen tartrate (37), norepinephrine hydrochloride (38), isoproterenol sulfate (39), 2,4,5-trimethoxyamphetamine hydrochloride (40), 4-ethyl-2,5-dimethoxyamphetamine (41), mescaline hydrobromide (42), and mescaline hydrochloride (43). 

After re-uptake by the nerve terminal a part of the released dopamine is converted to dihydroxyphenylacetic acid (DOPAC, 5) by intraneuronal monoamine oxidase (MAO) and aldehyde dehydrogenase (AD). Released dopamine is also converted to homovanillic acid (HVA, 6), probably at an extraneuronal site through the sequential action of catechol-O-methyltransferase (COMT) and MAO. In rat brain, DOPAC is the major metabolite and considerable amounts of DOPAC and HVA are present in sulfate-conjugated as well as free forms.1... 

Xenobiotic food additives, drugs, and biologically active endogenous compounds can interact and affect body biochemistry. For example, dopamine sulfotransferase activity is strongly inhibited by the colorant tartrazine and flavorant vanillin, and vanillin, erythrosine B, and octyl gallate inhibit the sulfation of 17 alpha-ethinylestradiol, a xenobiotic steroid J75l... 

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