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PubMed1999

Effects of nitric oxide synthase inhibition on sympathetically-mediated tachycardia.

The aim of the present study was to determine whether inhibition of nitric oxide (NO) synthesis directly alters the tachycardia produced by sympathetically-derived norepinephrine. The NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME; 50 micromol/kg, i.v.), produced a marked rise in mean arterial blood pressure. This pressor response was associated with a fall in heart rate which involved the withdrawal of cardiac sympathetic nerve activity. The NO-donor, sodium nitroprusside (5 microg/kg, i.v.), produced a pronounced fall in mean arterial blood pressure but only a minor increase in heart rate. The beta-adrenoceptor agonist, isoproterenol (0.5 micromol/kg, i.v.), and the membrane-permeable cAMP analogue, 8-(4-chlorophenylthiol)-cAMP (10 micromol/kg, i.v.), produced falls in mean arterial blood pressure and pronounced increases in heart rate. The indirectly acting sympathomimetic agent, tyramine (0.5 mg/kg, i.v.), produced a pressor response and a tachycardia. The effects of sodium nitroprusside, tyramine, isoproterenol and 8-(4-chlorophenylthiol)-cAMP on mean arterial blood pressure were not markedly affected by L-NAME. However, the tachycardia produced by these agents was considerably exaggerated in the presence of this NO synthesis inhibitor. These findings suggest that L-NAME potentiates the tachycardia produced by sympathetically-derived norepinephrine. The increased responsiveness to norepinephrine may involve (i) a rapid up-regulation of cardiac beta1-adrenoceptors and cAMP signaling in cardiac pacemaker cells due to the loss of the inhibitory influence of cardiac NO, and (ii) the up-regulation of beta1-adrenoceptor-mediated signal transduction processes in response to the L-NAME-induced withdrawal of cardiac sympathetic nerve activity.

Anesthesia↗
PubMed1983

A comparison of the blocking effect of alpha-adrenoceptor antagonist drugs towards directly and indirectly acting agonists on the rat vas deferens.

The antagonistic effect of dihydroergocristine and phentolamine towards the directly acting amine noradrenaline and the indirectly acting amine tyramine on the rat vas deferens was evaluated. It has been demonstrated that both alpha-adrenoceptor blocking drugs reduced the effect of the indirectly acting amine at concentrations lower than those needed to antagonize the action of noradrenaline. When concentrations of the alpha-adrenoceptor blocking drugs effective against noradrenaline were employed a qualitative difference in the antagonism towards the directly and indirectly acting amines has also been shown. It appears that in the rat vas deferens the effects induced by tyramine-released noradrenaline are more easily affected by alpha-adrenoceptor antagonist drugs than those induced by exogenously applied noradrenaline.

Adrenergic alpha-Antagonists↗
PubMed1978

Pressor amines and monoamine-oxidase inhibitors for treatment of postural hypotension in autonomic failure. Limitations and hazards.

The short-term effects of pressor amines were investigated in four patients with postural hypotension caused by autonomic failure. In supine patients p-tyramine alone or with a monoamine-oxidase inhibitor produced pronounced supine hypertension without abolishing the symptoms associated with a postural fall in blood-pressure. Phenylephrine or ephedrine maintained a normal blood-pressure on standing but caused supine hypertension. Thus the effects of p-tyramine with or without a monoamine-oxidase inhibitor were unpredictable and did not include relief of postural hypotension. Phenylephrine or ephedrine had some beneficial effect, but since all these drugs influence standing pressure only at the expense of pronounced supine hypertension, alternative therapy must be sought.

Aged↗
PubMed1988

Red wine as a cause of migraine.

Patients with migraine who believed that red wine but not alcohol in general had a headache-provoking effect on them were challenged either with red wine or with a vodka and diluent mixture of equivalent alcohol content, both consumed cold out of dark bottles to disguise colour and flavour. The red wine, which had a negligible tyramine content, provoked a typical migraine attack in 9 of 11 such patients, whereas none of the 8 challenged with vodka had an attack. Neither red wine nor vodka provoked such episodes in other migrainous subjects or controls. These findings show that red wine contains a migraine-provoking agent that is neither alcohol nor tyramine.

Alcoholic Beverages↗
PubMed1998

Characterization of [3H]idazoxan binding proteins in solubilized membranes from rabbit and human liver.

Several studies have shown that I2 imidazoline binding sites are localized on monoamine oxidases. Recent results obtained after solubilization of rat brain membranes and analysis by size-exclusion chromatography suggested the existence of additional I2 imidazoline binding sites located on proteins distinct from monoamine oxidases. In order to define whether such binding sites are expressed in human and rabbit liver, we solubilized I2 imidazoline binding sites and monoamine oxidases and compared their elution profile by size-exclusion chromatography. I2 binding sites were labeled using [3H]idazoxan. Monoamine oxidases were identified by the measure of [14C]tyramine oxidation and Western blot analysis using an anti-MAO-A/MAO-B polyclonal antiserum. After solubilization of rabbit or human liver using 1% digitonin, 90% of [3H]idazoxan binding eluted in a major peak corresponding to a Mr of approximately 175000 Da. A minor peak, (Mr approximately equal to 100000 Da) representing 10% of the recovered [3H]idazoxan binding, was also observed. [14C]tyramine oxidation as well as immunoreactive bands corresponding to MAOs were exclusively detected in fractions containing [3H]idazoxan binding. These results show that solubilized I2 imidazoline binding sites distinct from monoamine oxidases are not detectable in rabbit and human liver.

Adrenergic alpha-Antagonists↗
PubMed1999

Effect of proteolytic starter cultures of Staphylococcus spp. on biogenic amine formation during the ripening of dry fermented sausages.

The effect of proteolytic starter cultures of Staphylococcus carnosus and Staphylococcus xylosus on biogenic amine production was examined during the fermentation process of dry sausages. Microbial counts (lactic acid bacteria, Micrococcaceae and Enterobactenaceae), pH, moisture and proteolysis-related parameters were also studied. The polyamines spermine and spermidine were the main amines found in the raw material and they only showed slight fluctuations during the fermentation. The four elaborated batches presented a significant (P < 0.001) formation of tyramine and putrescine. The main rate of amine production was during the first three days, when a sharp pH decrease and the development of lactic acid bacteria occurred. Sausages fermented with starters had lower amounts of tyramine than naturally fermented sausages (control), but differences in the Micrococcaceae counts were only significant during the first week of the ripening process. A slight formation of diaminopropane, cadaverine, agmatine, tryptamine and phenylethylamine was observed. The amounts of histamine were constant and remained below 0.5 mg/kg of dry matter, while serotonin, octopamine and dopamine were not detected. The sausages with Staphylococcus as starter culture showed strong proteolysis that was correlated with higher pH values than those of the control sausages. However, no positive correlation was found between the proteolysis index and biogenic amine production. Since proteolysis was stronger during the second half of the ripening process, the release of free amino acids as amine precursors occurred later than the early amine production.

Animals↗
PubMed2000

Differential effect of structural modification of human dopamine transporter on the inward and outward transport of dopamine.

The effect of structural modification of the human dopamine transporter protein on bi-directional transport was explored using site-directed mutagenesis and rotating disk electrode voltammetry. The substrate-induced DA efflux, as inferred from the K(m) or K(i), was dependent on common structural features for uptake of the substrate inducer: reduced by beta-hydroxylation, stereoselective to alpha-methylation, and relatively insensitive to a switch of a single phenolic hydroxyl group between m- and p-positions. The potencies for substrates to compete with external DA for uptake and to induce DA efflux were similar and highly correlated. Despite these similarities, the efflux of internal DA was substantially slower than the uptake of its inducers. Mutation of serine-528 of the hDAT to alanine (S528A) did not change the structure-activity relationships, maximal uptake rates, and the cation dependence for the uptake of external substrates, although it modestly reduced K(m) or K(i) of most tested substrates. In contrast, it substantially enhanced substrate-induced DA efflux, with maximal efflux rates doubled for all tested inducers. Simultaneous monitoring of tyramine uptake and resulting DA efflux revealed that S528A accelerated the DA efflux relative to tyramine uptake. Saturation analysis suggested that the mutation significantly enhanced the efflux kinetics of internal DA but it exerted little effect on the uptake kinetics of external DA. These findings suggest that Ser-528 may play a role in stabilizing a hDAT conformation unfavorable for outward transport of internal DA, thereby contributing to the efficiency of the transporter.

Alanine↗
PubMed1979

Longitudinal urinary trace amine excretion in a human male.

The urinary excretion of a beta-phenylethylamine (PE), m-tyramine (mTA), p-tyramine (pTA) and tryptamine (TR) in their unconjugated (free) and conjugated (except tryptamine) forms, was examined in a male human subject over a total period of 28 days. The average excretion values were (in microgram per 24 h, mean +/- standard error): PE, free 3.19 +/- 0.21, conjugated 6.85 +/- 0.52, mTA, free 98.0 +/- 2.2, conjugated 106.1 +/- 18.6; pTA, free 427 +/- 12, conjugated 571 +/- 142; and TR, free 79.4 +/- 2.8. This data, when considered along with other published information, permits the suggestion that probably mTA and pTA in the unconjugated form are exclusively formed endogenously; whether or not this also pertains to PE and TR is less clear. In all cases, the conjugated amines derive from both exogenous and endogenous sources.

Humans↗
PubMed2001

Assessment of the serotonin and norepinephrine reuptake blocking properties of duloxetine in healthy subjects.

Duloxetine is a dual inhibitor of norepinephrine (NE) and serotonin (5-HT) uptake. Initial trials conducted in depressed patients using regimens of 20 mg/day or less did not convincingly demonstrate its efficacy as an antidepressant. The aim of this study was to assess the effects of duloxetine on the 5-HT and NE reuptake processes in healthy human volunteers. Twenty-seven healthy young males without a history of psychiatric disorder were randomly assigned to four groups, each group receiving one of the following daily drug regimens: placebo, clomipramine (a potent 5-HT/NE reuptake blocker) 100 mg/day, duloxetine 20 mg/day, or duloxetine 60 mg/day. In order to assess the NE reuptake process, the pressor response to intravenous tyramine (4 and 6 mg) was measured. Determination of the whole blood 5-HT content was used to evaluate the 5-HT reuptake blockade. These measurements were performed at baseline and repeated after 7 and 14 days of drug intake. Both duloxetine, at doses of 20 to 60 mg/day, and clomipramine significantly interfered with the 5-HT reuptake process, as demonstrated by marked decreases in blood 5-HT concentrations. However, the same doses of duloxetine, unlike clomipramine, failed to impede the usual increase in blood pressure that follows a tyramine intravenous infusion, indicating that clomipramine but not duloxetine blocked NE reuptake. At doses tested in a population of healthy volunteers, duloxetine acted as a selective 5-HT reuptake inhibitor, having no clear effect on the NE reuptake process. Nevertheless, given that the highest dose of duloxetine increased supine systolic blood pressure, it is possible that it represents the threshold regimen for NE reuptake inhibition.

Adolescent↗
PubMed1996

Synthesis and sulfatase inhibitory activities of non-steroidal estrone sulfatase inhibitors.

About one-third of breast cancers are classified as estrogen-dependent breast cancers. In the past 10 years, numerous reports have suggested the importance of estrone sulfate and estrone sulfatase in regulating the supply of estrogens to these cancers. Estrone sulfatase inhibitors may thus prove to be useful for the treatment of these diseases. Several research groups have reported the development of estrone sulfatase inhibitors, and estrone-3-O-sulfamate has been shown to be the most potent sulfatase inhibitor. However, a recent report indicated that estrone may be released during the inactivation of sulfatase by estrone-3-O-sulfamate and rendered the inhibitor to be estrogenic. Therefore, there is a need for a potent non-steroidal sulfatase inhibitor that is metabolically stable, more selective, and lacking estrogenic activity. We developed a series of (p-O-sulfamoyl)-N-alkanoyl tyramines, and they proved to be potent estrone sulfatase inhibitors. Using human placental microsome as the enzyme source, the best inhibitor in this series, compound 18, has an IC50 of 55.8 nM. Another potent inhibitor in this series, compound 17, exhibited time-dependent inactivation of sulfatase when incubated at various concentrations (0.2-1.0 microM) of the inhibitor. Estrone sulfate partially blocked the inactivation of the enzyme by the compound, indicating that the compound inactivated sulfatase at the active site. The irreversible nature of the enzyme-inhibitor interaction was supported by irreversibility studies. Thus, (p-O-sulfamoyl)-N-alkanoyl tyramines represent a new series of non-steroidal estrone sulfatase inhibitor.

Binding Sites↗
PubMed2001

Phenolamine-dependent adenylyl cyclase activation in Drosophila Schneider 2 cells.

Drosophila Schneider 2 (S2) cells are often employed as host cells for non-lytic, stable expression and functional characterization of mammalian and insect G-protein-coupled receptors (GPCRs), such as biogenic amine receptors. In order to avoid cross-reactions, it is extremely important to know which endogenous receptors are already present in the non-transfected S2 cells. Therefore, we analyzed cellular levels of cyclic AMP and Ca2+, important second messengers for intracellular signal transduction via GPCRs, in response to a variety of naturally occurring biogenic amines, such as octopamine, tyramine, serotonin, histamine, dopamine and melatonin. None of these amines (up to 0.1 mM) was able to reduce forskolin-stimulated cyclic AMP production in S2 cells. Furthermore, no agonist-induced calcium responses were observed. Nevertheless, the phenolamines octopamine (OA) and tyramine (TA) induced a dose-dependent increase of cyclic adenosine monophosphate (AMP) production in S2 cells, while serotonin, histamine, dopamine and melatonin (up to 0.1 mM) did not. The pharmacology of this response was similar to that of the octopamine-2 (OA2) receptor type. In addition, this paper provides evidence for the presence of an endogenous mRNA encoding an octopamine receptor type in these cells, which is identical or very similar to OAMB. This receptor was previously shown to be positively coupled to adenylyl cyclase.

Adenosine Monophosphate↗
PubMed2003

Intolerance to dietary biogenic amines: a review.

OBJECTIVE: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. DATA SOURCES: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allerg*, intoler*, and adverse. Additionally, the keywords histamine, tyramine, and phenylethylamine were combined with headache, migraine, urticaria, oral challenge, and oral provocation. Articles were also selected from references in relevant literature. STUDY SELECTION: Only oral challenge studies in susceptible patients were considered. Studies with positive results (ie, studies in which an effect was reported) were only eligible when a randomized, double-blind, placebo-controlled design was used. Eligible positive result studies were further evaluated according to a number of scientific criteria. Studies with negative results (ie, studies in which no effect was reported) were examined for factors in their design or methods that could be responsible for a false-negative outcome. Results of methodologically weak or flawed studies were considered inconclusive. RESULTS: A total of 13 oral challenge studies (5 with positive results and 8 with negative results) were found. Three of them (all with positive results) were considered ineligible. By further evaluation of the 10 eligible studies, 6 were considered inconclusive. The 4 conclusive studies all reported negative results. One conclusive study showed no relation between biogenic amines in red wine and wine intolerance. Two conclusive studies found no effect of tyramine on migraine. One conclusive study demonstrated no relation between the amount of phenylethylamine in chocolate and headache attacks in individuals with headache. CONCLUSIONS: The current scientific literature shows no relation between the oral ingestion of biogenic amines and food intolerance reactions. There is therefore no scientific basis for dietary recommendations concerning biogenic amines in such patients.

Administration, Oral↗
PubMed2006

Effects of different doses of venlafaxine on serotonin and norepinephrine reuptake in healthy volunteers.

Venlafaxine is generally considered to be a dual 5-HT and NE reuptake inhibitor when it is used at doses above 75 mg/d in humans. While its 5-HT reuptake-inhibiting property has been demonstrated, some controversy still exists regarding the doses of venlafaxine required to inhibit NE reuptake. Healthy male volunteers received, on a double-blind basis, paroxetine (20 mg/d), desipramine (100 mg/d), nefazodone (300 mg/d), or venlafaxine (150 or 300 mg/d) in the last 5 d of a 7-d period of administration. Inhibition of 5-HT reuptake was estimated by determining the degree of depletion of whole-blood 5-HT, while that of NE was assessed by measuring the attenuation of the systolic blood pressure increases produced by intravenous injections of tyramine. Paroxetine, both regimens of venlafaxine, and to a lesser extent desipramine significantly decreased whole-blood 5-HT content. Nefazodone failed to produce any significant change. Desipramine abolished the tyramine pressor response, whereas all other drug regimens left this parameter unaltered. Venlafaxine and paroxetine acted as potent 5-HT reuptake inhibitors in the present study. In contrast, neither the moderate nor the high dose of venlafaxine displayed any significant inhibiting activity in this model assessing NE reuptake in peripheral NE terminals. The validity of the model was confirmed by the potent inhibitory action of desipramine on NE reuptake. While the reasons for this unexpected lack of action remain unclear, venlafaxine appeared to be an effective NE reuptake agent in depressed patients using the same approach.

Adrenergic Uptake Inhibitors↗
PubMed1985

Human brain monoamine oxidase type B: mechanism of deamination as probed by steady-state methods.

Recently, evidence has been published which suggests that [Husain, M., Edmondson, D. E., & Singer, T.P. (1982) Biochemistry 21, 595-600] monoamine oxidase [amine:oxygen oxidoreductase (MAO), EC 1.4.3.4] deaminates phenylethylamine and benzylamine via two distinct kinetic pathways which involve either binary or ternary complex formation, respectively. These conclusions were drawn largely from stopped-flow kinetic analysis performed on purified enzyme removed from its native membrane and in the presence of the inhibitory detergent Triton X-100. In this study, d-amphetamine and alternative substrates were used as steady-state probes of the kinetics of deamination by the B form of human brain MAO using native membrane-bound enzyme. Initial velocity studies showed mixed-type patterns for amphetamine inhibition of phenylethylamine, tryptamine, and tyramine when either amine or oxygen was the varied substrate. Slope and intercept vs. amphetamine concentration replots were linear in all cases except for phenylethylamine (hyperbolic); Ki values obtained from linear replots of slope or intercept values were comparable. In contrast, amphetamine was a competitive inhibitor of benzylamine deamination when amine concentration was varied and uncompetitive when oxygen concentration was varied; slope and intercept replots were linear for both. When benzylamine was the alternative substrate inhibitor and tyramine and tryptamine deamination was measured, mixed-type inhibition patterns were obtained when either amine or oxygen concentration was varied; replots of slope and intercept were linear in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1989

Correlation of copper valency with product formation in single turnovers of dopamine beta-monooxygenase.

Chemical- and freeze-quench EPR techniques have allowed single-turnover studies of the copper-containing enzyme dopamine beta-monooxygenase. Reduction of enzyme by a stoichiometric amount of ascorbate followed by rapid mixing with tyramine leads to oxidation of bound copper and formation of hydroxylated product in the expected 2:1 ratio. The tyramine dependence of single turnovers yields a limiting rate of 82 +/- 9 s-1 and Km of 3 +/- 1 mM, in agreement with kinetic modeling based on steady-state parameters. Together these results show that the reduced enzyme is a catalytically competent species, with bound copper acting as the sole reservoir of reducing equivalents. The correlation of copper oxidation and substrate hydroxylation rules out significant antiferromagnetic spin coupling in the enzyme-product complex. Since the enzyme-product complex's Cu2+ EPR signal is absent in the transient approach to the steady state [Brenner, M. C., Murray, C. J., & Klinman, J. P. (1989) Biochemistry (preceding paper in this issue)], this result implies that ascorbate reduces copper in the enzyme-product complex. These findings have important consequences for catalysis and active site structure in dopamine beta-monooxygenase.

Animals↗
PubMed2002

Effects of high hydrostatic pressure treatments on biogenic amine contents in goat cheeses during ripening.

The application of high-pressure treatment to accelerate cheese ripening may influence the occurrence and profile of biogenic amines. In some cases, high-pressure treatment could yield high amine content, whereas in others the amine concentrations were comparable with those in nontreated ones. Tyramine was the most affected amine. However, the influence of high pressure depended on the treatment applied. The highest amine concentrations were observed when 50 MPa for 72 h was applied, and in which, the content of tyramine was almost three times higher than in the untreated samples. On the contrary, when 400 MPa for 5 min or 400 MPa for 5 min plus 50 MPa for 72 h were applied contents of this amine were similar or lower than those found in control cheeses showing similar degrees of proteolysis. The higher proteolysis, induced by the pressurization treatments, was not correlated with the higher amine production.

Amino Acids↗
PubMed2006

Influence of lupin (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) germination on microbial population and biogenic amines.

Microbial population and bioactive amine profile and levels of two lupin species (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) seeds as affected by germination were investigated. Microbial population increased considerably mainly in the first stage of germination (2 days), then small changes in bacterial numbers were observed up to 5 days to levels between 7.8 and 8.9 log colony-forming units/g. Microorganisms belonging to the Enterobacteriaceae family were dominant for the legumes tested. Ungerminated legume seeds contained putrescine, cadaverine, histamine, tyramine, spermidine, and spermine. Bioactive amine levels found in fenugreek seeds were between 3- and 4-fold higher than those found in lupin seeds. The highest total amine levels were found in fenugreek seeds [162 mg/kg of dry weight (dw)], followed by L. angustifolius var. zapaton seeds (84 mg/kg of dw) and, finally, L. luteus cv. 4492 (46 mg/kg of dw) seeds. The concentration of individual amines showed a gradual rising trend during the germination period in all tested sprouts, reaching levels >3 times higher than those found in ungerminated seeds. After 5 days of germination, the fenugreek sprouts contained the highest amount of total bioactive amines. Tyramine was the predominant amine in both lupin varieties, whereas cadaverine was the main bioactive amine detected in fenugreek. The results of this work thus indicated that microbial population and biogenic amine levels in the studied lupin and fenugreek sprouts are not a risk for healthy consumers or for individuals with restricted activity of detoxification enzymes.

Biogenic Amines↗
PubMed1992

Benzodiazepine receptor affinity and interaction of some N-(indol-3-ylglyoxylyl)amine derivatives.

Several derivatives, in which tryptamine, tyramine, and dopamine moieties are linked to the indole nucleus by an oxalyl bridge, were tested for their ability to displace the specific binding of [3H]flunitrazepam from bovine brain membranes. GABA ratio and in vivo tests for the most potent compounds showed they behave as inverse agonists at the benzodiazepine receptor (BzR). To better define the structure-activity relationship (SAR) of this kind of ligand, several phenylethylamine derivatives were synthesized to evaluate their affinity to BzR. Some of these derivatives (17, 21, 24, 26, and 30) were found to exhibit high affinity (Ki = 0.51-0.085 microM) for BzR and possessed a partial agonist activity, although their chemical structure is closely related to tryptamine 2-6, tyramine 7-11, and dopamine 12-16 derivatives. A different interaction of these ligands to the receptor site is hypothesized. Moreover, all the prepared 1-methyl derivatives exhibited very low binding affinity to BzR.

Animals↗