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PubMed1991

Lithium does not alter the renal response to a pressor dose of tyramine in man.

Renal clearance of lithium has been used as a marker of proximal tubular function in man. Recently, lithium pre-treatment has been shown to interfere with the natriuretic actions of some natriuretic agents in man. We have therefore investigated the effects of oral lithium carbonate (500 mg) on the natriuretic response to a pressor dose of tyramine (15 micrograms kg-1 min-1) in six normal volunteers. Lithium had no effect on baseline sodium excretion, nor did it affect the tyramine-induced increase in blood pressure and subsequent natriuresis. These results show that oral lithium carbonate (500 mg) does not appear to interfere with the pressure natriuretic response to tyramine in man.

Adult↗
PubMedDate not supplied

The effect of corticotrophin (ACTH) administration on the pressor action of angiotensin II, noradrenaline and tyramine in sheep.

1. Pressor responses to angiotensin II, noradrenaline and tyramine were examined in sheep prior to and during the development of corticotrophin-induced hypertension. 2. Pressor responses to angiotensin II amide did not change with corticotrophin (ACTH) administration. Small significant increases in pressor responses to noradrenaline occurred at low doses only (0.27 and 1.06 mumol/h). Significant increases in response to tyramine occurred after 24h of ACTH administration, but were not maintained after 6 days of ACTH. These changes are quantitatively small and do not suggest that changes in pressor sensitivity contribute significantly to the rise in blood pressure following ACTH administration. 3. Sodium depletion significantly reduced the pressor responses to angiotensin II amide at all doses and to tyramine in the middle range only, but did not affect the responses to noradrenaline.

Adrenocorticotropic Hormone↗
PubMed1983

Decarboxylation of p-tyrosine: a potential source of p-tyramine in mammalian tissues.

The question of the existence of a p-tyrosine decarboxylase pathway for the formation of p-tyramine in mammalian tissues remains unresolved. Development of a sensitive and specific assay for p-tyrosine decarboxylase has permitted demonstration of this activity in rat tissues and human kidney. Tyrosine decarboxylase was purified to electrophoretic homogeneity by pH 5.0 precipitation, ammonium sulfate precipitation, gel filtration, phenyl-Sepharose chromatography, DEAE-Sephacel chromatography, and preparative isoelectric focusing. A specific rabbit antiserum to tyrosine decarboxylase was also obtained. Purified tyrosine decarboxylase possessed a narrow pH dependency with an optimum at 8.0. Benzene and certain other organic solvents dramatically stimulated tyrosine decarboxylase activity of purified enzyme. Purified tyrosine decarboxylase activity also decarboxylated L-DOPA, 5-hydroxytryptophan, 3,4-dihydroxyphenylserine, o-tyrosine, m-tyrosine, phenylalanine, histidine, and tryptophan, which suggested that the purified enzyme was aromatic L-amino acid decarboxylase. This conclusion was supported by a constant ratio of 5-hydroxytryptophan decarboxylase to tyrosine decarboxylase throughout the purification scheme and by parallel immunoprecipitation of decarboxylase activities by the specific antityrosine decarboxylase antisera. Thus, we report that p-tyrosine is decarboxylated by aromatic L-amino acid decarboxylase and that this metabolic transformation may be an important source of p-tyramine in mammalian tissues. In conclusion, neuronal tissues that synthesize catecholamines or serotonin should now be considered capable of synthesizing p-tyramine and other biogenic amines.

Animals↗
PubMed1983

Changes in levels of dopamine and tyramine in the rat caudate nucleus following alterations in impulse flow in the nigrostriatal pathway.

Following electric stimulation of the substantia nigra for 1 h there was a substantial increase in dopamine (DA) turnover in the rat caudate nucleus evidenced by an increase in its acid metabolite homovanillic acid (HVA). Concurrently there was an increase in striatal m-tyramine (mTA) and a substantial decrease in p-tyramine (pTA). Lesioning the substantia nigra to decrease impulse flow resulted in a buildup of striatal DA and mTA, but again a decrease in pTA. Following pretreatment with a tyrosine hydroxylase inhibitor, the effects of stimulation of the nigra on mTA were reversed, there being a significant decrease in this amine. The decrease of pTA in response was partially prevented by tyrosine hydroxylase inhibition. The effects of stimulation or substantia nigra lesions on pTA levels were reversed, however, by tyrosine hydroxylase inhibition, a significant increase in this amine being recorded. mTA and DA levels were largely unaffected by a combination of lesion and tyrosine hydroxylase inhibition. The results provide insight into the possible biosynthetic interrelationships between DA and the tyramine isomers in the rat caudate nucleus.

Anesthesia, General↗
PubMed1960

The effect of precursors of noradrenalin on the response to tyramine and sympathetic stimulation.

Previous observations have shown that the effects of sympathetic stimulation and of tyramine were absent in the organs of animals treated with reserpine, but that they were restored by an infusion of noradrenaline. Observations are described showing that an infusion of adrenaline did not restore the pressor action of tyramine in the cat or in the rat, but that in the rat the pressor action was restored by an infusion of dopamine, or of (-)-dopa, or of m-tyrosine,or of phenylalanine. Observations are also described showing that the effect of postganglionic stimulation of the fibres to the nictitating membrane and to the iris was restored by an infusion of dopamine or of (-)-dopa; it was restored less well by an infusion of noradrenaline. An infusion of noradrenaline did not restore the action of tyramine on the denervated iris or on the denervated vessels of the cat's foreleg. An infusion of noradrenaline appeared to increase the effect of sympathetic stimulation of the hypogastric nerves to the uterus of the virgin cat about as much as an infusion of adrenaline. An infusion of noradrenaline restored the constrictor action of nicotine on the perfused vessels of the rabbit ear.

Animals↗
PubMed1970

The role of monoamine oxidase in the response of the isolated central artery of the rabbit ear to tyramine.

1. Monoamine oxidase activity was demonstrated histochemically throughout the media of the rabbit ear artery but not in the adventitia at its border with the media where the sympathetic nerve terminals are concentrated. Neither intensity nor distribution of enzyme activity was perceptibly altered up to 60 days after sympathetic denervation.2. Iproniazid and nialamide increased the sensitivity of the artery to intraluminal tyramine much more than that to extraluminal tyramine, so that the difference between the potencies for the two routes of administration became less marked.3. The results indicate that inactivation by monoamine oxidase in the media is a factor contributing to the relatively low potency of intraluminal tyramine on the artery.

Animals↗
PubMed1971

Effect of tyramine on human umbilical artery in vitro.

Fifteen of twenty-one perfused human umbilical artery preparations constricted in response to tyramine. These responses were unaffected by atropine, mepyramine or bromolysergic acid diethylamide but were blocked by phentolamine or dihydroergotamine. Cocaine augmented the constriction responses to tyramine or noradrenaline but not those to adrenaline, acetylcholine or 5-hydroxytryptamine. Infusion of noradrenaline restored the responses of preparations which had become tachyphylactic to tyramine.

Atropine↗
PubMed1991

Interaction of 1-methyl-4-phenylpyridinium ion and tyramine with a site putatively involved in the striatal vesicular release of dopamine.

The neurotoxin MPP+ potently inhibited the striatal binding of [3H]-tyramine, a putative marker for the vesicular transporter of dopamine, and provoked a massive in vivo release of striatal dopamine. Tetrabenazine, an established ligand for the vesicular catecholamine carrier, potently inhibited [3H]-tyramine binding, tyramine-provoked striatal efflux of dopamine and the fast component of MPP(+)-induced dopamine release. It is concluded that MPP+ in the striatum, besides interacting with additional intracellular targets, avidly binds at a vesicular site functionally involved with the outward transport of dopamine.

Animals↗
PubMed1990

Potentiation of the pressor effect of intravenously administered tyramine during moclobemide treatment.

Potentiation of the pressor effect of tyramine (TYR) by intravenous (i.v.) injection during moclobemide treatment was investigated in healthy volunteers and in depressed patients. The TYR sensitivity factor (TSF) is calculated as the ratio between the dose of TYR required to raise systolic blood pressure by 30 mmHg (TYR 30) without drug and that required with drug. After single-dose administration the TYR 30 for 100 mg moclobemide was 1.8 mg, and those for moclobemide 200 and 300 mg 1.6, compared with 3.2 for placebo, giving corresponding TSF values of 1.7, 2.0 and 2.0 respectively. Twenty-four hours after moclobemide intake, only the 300-mg dose yielded a mean TYR 30 value significantly different from placebo. The same doses of moclobemide given 3 times daily for 1 week resulted in a peak TSF of 2.0 with 100 mg, 2.9 with 200 mg and 3.3 with 300 mg (the latter dose being higher than normally recommended for 3 times daily administration). Nevertheless, 24 h after the last 300-mg dose the TSF was 1.2, similar to that of a single dose. In a study of 17 depressed female patients treated with moclobemide 100 mg 3 times daily, no relevant differences were found in TSF values from those of the volunteers. The authors conclude that, because of the short-lasting, reversible and selective MAO-A-inhibiting effect of moclobemide, there is no marked interaction with tyramine given by i.v. injection. No relevant difference was seen between depressed patients and healthy volunteers in the tyramine pressor effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressive Agents↗
PubMed1979

Interaction studies between three antidepressant drugs (chlorimipramine, imipramine and zimelidine) and noradrenaline, tyramine and vagal stimulation on the heart rate and blood pressure in dogs.

Anaesthetized Beagle dogs were given increasing intravenous doses of imipramine, chlorimipramine or zimelidine. At each dose interval the interference of the drug administered with the effects on blood pressure and heart rate of vagal stimulation, NA injection and tyramine injection was investigated. Also, the in vitro uptake of 5-HT into platelets after in vivo administration to unanaesthetized dogs of 5 mg chlorimipramine or 5 mg zimelidine was studied. Chlorimipramine and zimelidine were found to be about equipotent as regards 5 HT-uptake into platelets after in vivo administration. Imipramine and chlorimipramine potentiated the effects of NA after the 2 mg/kg dose. Imipramine but not chlorimipramine interfered with the effects of tyramine after the 4 mg/kg dose. Zimelidine did not interfere with either NA or tyramine at any dose level studied (maximal cumulative dose 62 mg/kg). The effect of vagal stimulation was significantly inhibited after 8 mg/kg (cumulative dose 14 mg/kg) of imipramine and 16 mg/kg (cumulative dose 30 mg/kg) of chlorimipramine and zimelidine, respectively. It is concluded that zimelidine in comparison with imipramine and chlorimipramine has no or at most a slight effect on peripheral adrenergic neurones. It has less pronounced anticholinergic properties than imipramine but is about equipotent to chlorimipramine in this respect.

Allylamine↗
PubMed2002

Identification of the Enterococcus faecalis tyrosine decarboxylase operon involved in tyramine production.

Screening of a library of Enterococcus faecalis insertional mutants allowed isolation of a mutant affected in tyramine production. The growth of this mutant was similar to that of the wild-type E. faecalis JH2-2 strain in Maijala broth, whereas high-performance liquid chromatography analyses showed that tyramine production, which reached 1,000 microg ml(-1) for the wild-type strain, was completely abolished. Genetic analysis of the insertion locus revealed a gene encoding a decarboxylase with similarity to eukaryotic tyrosine decarboxylases. Sequence analysis revealed a pyridoxal phosphate binding site, indicating that this enzyme belongs to the family of amino acid decarboxylases using this cofactor. Reverse transcription-PCR analyses demonstrated that the gene (tdc) encoding the putative tyrosine decarboxylase of E. faecalis JH2-2 is cotranscribed with the downstream gene encoding a putative tyrosine-tyramine antiporter and with the upstream tyrosyl-tRNA synthetase gene. This study is the first description of a tyrosine decarboxylase gene in prokaryotes.

Amino Acid Sequence↗
PubMed1978

Genetic mapping of tyramine oxidase and arylsulfatase genes and their regulation in intergeneric hybrids of enteric bacteria.

The genes for arylsulfatase (atsA) and tyramine oxidase (tynA) have been mapped in Klebsiella aerogenes by P1 transduction. They are linked to gdhD and trp in the order atsA-tynA-gdhD-trp-pyrF. Complementation analysis using F' episomes from Escherichia coli suggested an analogous location of these genes in E. coli, although arylsulfatase activity was not detected in E. coli. P1 phage and F' episomes were used to create intergeneric hybrid strains of enteric bacteria by transfer of the ats and tyn genes between K. aerogenes, E. coli, and Salmonella typhimurium. Intergeneric transduction of the tynK gene from K. aerogenes to an E. coli restrictionless strain was one to two orders less frequent than that of the leuK gene. The tyramine oxidase of E. coli and S. typhimurium in regulatory activity resemble very closely the enzyme of K. aerogenes. The atsE gene from E. coli was expressed, and latent arylsulfatase protein was formed in K. aerogenes and S typhimurium. The results of tyramine oxidase and arylsulfatase synthesis in intergeneric hybrids of enteric bacteria suggest that the system for regulation of enzyme synthesis is conserved more than the structure or function of enzyme protein during evolution.

Arylsulfatases↗
PubMed1990

A sulfur- and tyramine-regulated Klebsiella aerogenes operon containing the arylsulfatase (atsA) gene and the atsB gene.

The structural gene for arylsulfatase (atsA) of Klebsiella aerogenes was cloned into a pKI212 vector in Escherichia coli. Deletion analysis showed that the atsA gene with the promoter region was located within a 3.2-kilobase cloned segment. In E. coli cells which carried the plasmid, the synthesis of arylsulfatase was repressed by various sources of sulfur; the repression was relieved, in each case, by tyramine. Transfer of the plasmid into atsA or constitutive atsR mutant strains of K. aerogenes resulted in complementation of atsA but not of atsR. The nucleotide sequence of the 3.2-kilobase fragment was determined. Two open reading frames, the atsA gene and an unknown gene (atsB), were found. These are located between a potential promoter and a transcriptional terminator sequence. Deletion analysis suggests that atsB is a potential positive factor for the regulation of arylsulfatase. Analysis of the amino acid sequences of the first 13 amino acids from the N terminus of the purified secreted arysulfatase agrees with that of the nucleotide sequence of atsA. The leader peptide extends over 20 amino acids and has the characteristics of a signal sequence. Primer extension mapping of transcripts generated in vivo suggests that the synthesis of mRNA starts at a site 31 or 32 bases upstream from the ATG initiation codon of the atsB gene. By Northern (RNA) blot analysis of the transcripts induced by tyramine, we found a 2.7-kilobase transcript which is identical in size to the total sequence of the atsB and atsA genes. Thus, the ats operon is composed of two cistrons and is regulated by sulfur and tyramine.

Amino Acid Sequence↗
PubMed1987

Atrial fibrillation precipitated by tyramine containing foods.

Episodes of atrial fibrillation that occurred after meals developed in a 60 year old man with a history of ischaemic heart disease. The attacks were precipitated by precursors and metabolites of tyramine and tyramine containing foods and drinks, in the absence of monoamine oxidase inhibitors. The patient has remained free of atrial fibrillation for the past twelve months on a diet that does not contain tyramine.

Atrial Fibrillation↗
PubMed1987

Supersensitivity to both tyramine and noradrenaline in diabetic autonomic neuropathy.

Cardiovascular responses to intravenously infused tyramine and noradrenaline were measured in five normal subjects, five insulin-dependent diabetics and five insulin-dependent diabetics with autonomic neuropathy. Tyramine infusion produced a statistically significant increase in systolic blood pressure (BP) in the autonomic neuropaths only (p less than 0.001). No change occurred in diastolic BP. Noradrenaline infusion produced a statistically significant increase in systolic BP in the normal subjects (p less than 0.01) and in the autonomic neuropaths (p less than 0.001). The increase in systolic BP in the neuropaths was significantly greater (p less than 0.001) than in normal subjects. Diastolic BP rose significantly only in the normal subjects (p less than 0.05). There was no change in heart rate in response to either agent. Thus super-sensitivity to noradrenaline occurred in patients with diabetic autonomic neuropathy indicating post-denervation hypersensitivity. Tyramine hypersensitivity also occurred indicating that denervation is not complete and suggesting dysfunction at a pre-synaptic level.

Adult↗
PubMed1999

Detection of immunoglobulin light chain mRNA by in situ hybridisation using biotinylated tyramine signal amplification.

A highly sensitive method for the light microscopic in situ hybridisation of immunoglobulin light chain mRNA in formalin fixed, paraffin wax embedded sections is reported. This method is based on signal amplification using horseradish peroxidase catalysed deposition of biotinylated tyramine at the sites of hybridisation. kappa and lambda light chain immunoglobulin mRNA in situ hybridisation was performed with fluorescein isothiocyanate conjugated oligonucleotide probe cocktails. The hybridisation signal was detected using a biotinylated tyramine signal amplification procedure with streptavidinbiotin-horseradish peroxidase complex as the final layer. Peroxidase was demonstrated using 3,3'-diaminobenzidine. The biotinylated tyramine signal amplification method resulted in the sensitive detection of immunonoglobulin light chain mRNA, with the whole procedure being completed in one day. Moreover, the use of peroxidase as the final reporter molecule also allowed haemamatoxylin to be used as counterstain, thereby permitting the evaluation of cellular morphology.

Biotinylation↗
PubMed1979

N-acylation of tyramines: purification and characterization of an arylamine N-acetyltransferase from rat brain and liver.

The N-acylation of tyramine isomers and other biogenic amines has been studied. The liver exhibits the highest activity towards tyramines, while the brain exhibits a low but significant activity. In the brain, tyramine N-acylation activity was heterogenously distributed. The arylamine N-acetyltransferase has been partially purified from both rat liver and brain, the two enzymes being quite similar with respect to their chromatographic properties, optimal pH requirement (pH 7.8), and their kinetic parameters. The product N-acetyltyramine is not oxidized by liver amidohydrolase or monoamine oxidase.

Acetyltransferases↗
PubMed1979

Tyramine infusions in bipolar illness: behavioral effects and longitudinal changes in pressor sensitivity.

Steady state intravenous tyramine dose pressor-response tests were administered to a patient with bipolar illness during depressed and hypomanic phases of her illness. The greatest tyramine sensitivity while unmedicated occurred when the patient was hypomanic, and the least sensitivity when she was depressed before her first switch. The data raise the possibility that changes in peripheral alpha-adrenergic receptor sensitivity accompany spontaneous mood cycles. Tyramine produced a replicable mood and cognitive alteration only in the infusion closest to the switch from hypomania to depression, suggesting that the CNS may be particularly susceptible to peripheral noradrenergic inputs at specific points in bipolar illness.

Adult↗