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PubMed2004

Elusive amines and cluster headache: mutational analysis of trace amine receptor cluster on chromosome 6q23.

Cluster headache (CH) is characterised by unilateral pain and ipsilateral autonomic features. To date, no molecular genetic evidence has been shown for CH. Small pedigrees and low penetrance render the identification of the CH-gene quite difficult. Nonetheless the association of CH and migraine to a new class of amine, namely trace or elusive amines such as tyramine, octopamine and synephrine, has recently been demonstrated. In particular, in comparison to healthy control subjects, all these neurotransmitters have been found to be greatly elevated in CH sufferers in plasma and platelets both in active and remission periods. A cluster of gene-encoding G-protein-coupled receptors that bind and are activated by trace amines was identified in the long arm of chromosome 6q23. We evaluated two families with CH by linkage analysis to 6q23 region and the mutation scanning of the TAR 1, TAR 3, TAR 4, TAR 5, PNR and GPR58 genes by denaturing high liquid chromatography is in progress in 16 familial cases.

Biogenic Amines↗

PubMed1988

Distribution of biogenic amines in the cricket central nervous system.

The distribution of biogenic amines, their precursors, and metabolites in the central nervous system (CNS) of the cricket was determined using HPLC with electrochemical detection. Three biogenic amines, octopamine (OA), dopamine (DA), and 5-hydroxytryptamine (5-HT); two precursors, tyramine and tryptophan; and two metabolites, synephrine and 5-hydroxyindole-3-acetic acid, were detected in all ganglia. In the brain, 5-HT occurred in the largest quantities followed by OA, while in other ganglia OA occurred in the largest quantities followed by 5-HT and DA. In all ganglia, the amount of OA was two to nine times greater than that of DA. The results are discussed in comparison with different insect species.

Animals↗

PubMed1986

Purification and properties of synephrinase from Arthrobacter synephrinum.

Synephrinase, an enzyme catalyzing the conversion of (-)-synephrine into p-hydroxyphenylacetaldehyde and methylamine, was purified to apparent homogeneity from the cell-free extracts of Arthrobacter synephrinum grown on (+/-)-synephrine as the sole source of carbon and nitrogen. A 40-fold purification was sufficient to produce synephrinase that is apparently homogeneous as judged by native polyacrylamide gel electrophoresis and has a specific activity of 1.8 mumol product formed/min/mg protein. Thus, the enzyme is a relatively abundant enzyme, perhaps comprising as much as 2.5% of the total protein. The enzyme essentially required a sulfhydryl compound for its activity. Metal ions like Mg2+, Ca2+, and Mn2+ stimulated the enzyme activity. Metal chelating agents, thiol reagents, denaturing agents, and metal ions like Zn2+, Hg2+, Ag1+, and Cu2+ inhibited synephrinase activity. Apart from (-)-synephrine, the enzyme acted upon (+/-)-octopamine and beta-methoxysynephrine. Molecular oxygen was not utilized during the course of the reaction. The molecular mass of the enzyme as determined by Sephadex G-200 chromatography, was around 156,000. The enzyme was made up of four identical subunits with a molecular mass of 42,000.

Arthrobacter↗

PubMed1991

Ceratitis capitata brain adenylate cyclase and its membrane environment.

Adenylate cyclase activation by GTP and octopamine as well as basal activity (in the presence of Mg2+) have been studied as a function of membrane structure in plasma membranes from brain of the dipterous Ceratitis capitata. Benzyl alcohol and lidocaine, but not phenobarbital, inhibited the three activities to the same extent. Triton X-100-solubilized adenylate cyclase was also inhibited by benzyl alcohol and lidocaine, but not by phenobarbital. Results could be explained by an effect on the catalytic unit lipid environment, which would be maintained after solubilization, counteracting the effect of these drugs to facilitate lateral diffusion and coupling of adenylate cyclase components in the lipid bilayer. The observation that the insect adenylate cyclase is relatively insensitive to changes in bulk bilayer fluidity is strengthened by the absence of effect of phenobarbital on enzyme activities. Indeed, this compound was as active as lidocaine or benzyl alcohol in increasing bulk membrane fluidity. The response of C. capitata adenylate cyclase to changes in membrane fluidity is different from that recorded in mammalian systems. This may be functionally important and result from the fact that insects are not warm-blooded.

Adenylyl Cyclases↗

PubMed1977

Effects of amines on macromolecular methylation.

Histone methylation by extracts of rat brain or liver was inhibited and tRNA methylation stimulated by the addition of a number of naturally occurring polyamines. The effect was age independent although the methylase activities are highly age-related. Spermine and/or histamine stimulated methylation of cytosine and adenine to a far grease activity, were more sensitive to inhibition by adenosine than were liver extracts. Adenosine inhibited the methylation of guanine to a greater extent than of cytosine or adenine. Methylation of both tRNA and histone by liver enzyme was inhibited by L-dopa, dopamine and epinephrine. Methylation by brain enzyme was also blocked, but less extensively. The response of liver extracts to these catecholamines was highly age-related. The phenolic amines, octopamine, synephrine, serotonin and tyramine, stimulated tRNA methylation slightly while inhibiting histone methylation by both liver and brain extracts and these effects showed no age dependency. Analysis of the data suggests that most of these compounds do not act by competing for the available S-adenosylmethionine.

Aging↗

PubMed1984

Excretion of catecholamines and their metabolites in transplantable rat phaeochromocytoma.

The urinary excretion pattern of catecholamines and their metabolites was studied in rats bearing a subcutaneous transplantable phaeochromocytoma. Compared with normal rats, tumour-bearing animals showed a markedly raised excretion of dopamine, noradrenaline and adrenaline, together with certain of their major acidic and alcoholic metabolites. No evidence of increased octopamine production could be obtained. There was a significant correlation between the output of dopamine and its metabolites, allowing accurate assessment of dopamine turnover rates which were comparable with those observed in human phaeochromocytoma. Tumour development, as determined by tumour weight, also correlated significantly with urinary excretion of noradrenaline and dopamine. Rat phaeochromocytoma appears to be a useful model for the human tumour.

3-Methoxy-4-hydroxyphenylethanol↗

PubMed1985

A modified Ecteola cellulose assay for M and P phenol sulfotransferase.

The development and applications of a modified Ecteola cellulose, ion exchange assay for phenol sulfotransferase (EC 2.8.2.1, PST) are described. Mixtures containing dopamine or phenol and 35S-labeled 3'-phosphoadenosine-5'-phosphosulfate (PAPS) were incubated with 100,000 g supernatant solution from human frontal cortex and applied to 0.5 X 2 cm columns of Ecteola cellulose. Dopamine sulfate was eluted with 3 ml of distilled water, while phenyl sulfate, inorganic sulfate and unreacted PAPS were eluted with successive step gradients of 5, 20 and 200 mM NH4HCO3. The solution volume for phenyl sulfate was 11 ml, while those for inorganic sulfate and PAPS were both 6 ml. The new assay method yielded apparent Km values for dopamine, 3-methoxytyramine, tyramine and norepinephrine similar to those obtained by other methods. Comparison of the activities of various amine substrates at a concentration of 20 microM showed that dopamine was the preferred substrate, followed in decreasing order of relative activity by 3-methoxytyramine, norepinephrine, tyramine and octopamine. When mixed substrate inhibition of dopamine sulfation by phenol was examined, phenol was found to effectively inhibit dopamine sulfation over a range of 0.1 to 10 mM. The procedure described in this paper offers a number of significant advantages over currently available assays: these include a rapid, simple product isolation procedure and a complete, discrete separation of the radiolabeled products and reactants. This property allows the detailed study of the flux of radiolabel through the enzymatic system and also makes alternative substrate inhibition studies possible.

Arylsulfotransferase↗

PubMed1988

On the mechanism of imipramine's influence in lowering p-hydroxyphenylglycol concentrations in the brain. The role of tyrosine.

Administration of imipramine (IMI) to rats was shown to lower after 4.5 hr the brain concentration of the octopamine metabolite p-hydroxyphenylglycol (pHPG) in a dose-dependent manner over the range of 10-40 mg/kg of IMI. Assay of plasma and brain levels of tyrosine revealed that IMI produced a reduction in both but with a shorter time-course than for the depletion in pHPG, with the maximal decreases occurring at 1.5 hr, before there was any loss of pHPG. The reductions in tyrosine and pHPG levels could not be explained by an effect of IMI on food intake, since the levels were diminished even in 24-hr fasted animals. When rats were injected with IMI 4.5 hr before 200 mg/kg of tyrosine and 5.5 hr before being killed, the elevation in brain pHPG levels were attenuated by about 50%, as compared to the animals that received tyrosine alone. These data suggest that the ability of IMI to lower brain pHPG probably involves two distinct mechanisms: (1) a lowering of brain and plasma tyrosine concentrations, and (2) an inhibition of the conversion of tyrosine to pHPG. It is unclear whether these effects are due to IMI itself or to one of its metabolites, such as desmethylimipramine or didesmethylimipramine, which were found in the plasma in amounts equal to or greater than IMI.

Animals↗

PubMed1986

Spectra of neurotransmitter receptors and ionic responses on cerebral A and B neurons in Aplysia californica.

Receptors to putative transmitters on A and B cells of Aplysia californica were identified and characterized. Neurons within each cluster were similar in responses to transmitters, but the neurons in A and B clusters differed. Both exhibited receptors to acetylcholine, dopamine, gamma-aminobutyric acid, glutamate, histamine and serotonin but not to octopamine or phenylethanolamine. Bi- or multiphasic responses to a single transmitter were common on both cell types. Inhibitory responses were more common on A than B cells where glutamate, histamine and serotonin were all excitatory. Each of these clusters appear homogeneous both in terms of presence of receptors and the ionic channels activated by the receptors.

Acetylcholine↗

PubMed1986

Specific detection of noradrenaline in the rat brain by using antibodies.

Noradrenaline (NA) was conjugated to different protein carriers with glutaraldehyde. During the catecholamine conjugate synthesis, precautions were taken in order to preserve the structure of NA. Anti-NA antibodies were raised in rabbits and tested using a modified enzyme-linked immunosorbent assay and immunocytochemistry. The most immunoreactive antigen was found to be the reduced NA conjugate. The octopamine conjugate was recognized by the NA antiserum 16 X less than the reduced NA conjugate. The other conjugates, dopamine, L-dihydroxyphenylalanine and adrenaline were poorly recognized by the anti-NA antibodies. A good correlation was found between results obtained using the in vitro enzyme-linked immunosorbent assay and immunocytochemistry.

Animals↗

PubMed1988

The presence of tyramine and related monoamines in the nerve cord and some other tissues of the lobster, Homarus americanus.

This report shows the existence of endogenous p-tyramine in the nerve cord and some organs of the lobster. Their concentrations are lower than those of dopamine or 5-hydroxytryptamine. The nerve cord levels of m-tyramine, beta-phenylethylamine and tryptamine are much lower than those of the phenolic or catecholic amines. The finding that the administration of an aromatic-L-amino acid decarboxylase inhibitor leads to a decrease of p-tyramine gives further evidence that this amine is synthesized from p-tyrosine, which is also found in high concentrations in the lobster nerve cord. The widespread distribution of p-tyramine in the nervous system and peripheral tissues of the lobster suggests that this amine may have additional roles rather than functioning only as a precursor of p-octopamine.

Animals↗

PubMed1979

Decreased cerebrospinal fluid concentration of free phenylacetic acid in depressive illness.

Cerebrospinal fluid free phenylacetic acid concentration in a series of depressive patients was significantly lower than values in control subjects. This acid derives from phenylethylamine and the findings may reflect a decrease in its brain formation. Such a deficit may be related to other recent observations of a decrease in urinary output of the major metabolites of the "trace amines", octopamine and tyramine: phenylethylamine is thought to be the precursor of these "trace amines".

Adult↗

PubMed1981

Preparation of antibodies to catecholamines and metabolites--syntheses of various immunogens and characterization of the resulting antibodies.

The synthesis of antigens of the haptens p-tyramine, octopamine, synephrine, dopamine, normetanephrine, beta-(3,4-dichlorophenyl)-ethylamine and 3-fluoro-tyramine is described. The coupling of the haptens to the carrier protein was performed either via the side chain by means of succinic anhydride, or through the phenolic ring via an aminomethyl group which was introduced by a Mannich reaction. Antisera to these haptens were produced in rabbits by immunization with these antigens. The antisera were characterized by determination of titer and specificity (p-tyramine, synephrine, normetanephrine). The possibility is discussed of using antisera to p-hydroxyphenylethylamine for a radioimmunological determination of catecholamines.

Animals↗

PubMed1977

The influence of adrenergic agonists and their antagonists on isolated salivary glands of ixodid ticks.

Various drugs elicit fluid secretion by isolated salivary glands of two species of ixodid ticks (Dermacentor andersoni Stiles and Amblyomma hebraeum Koch). Among catecholamines, the following order of potency was observed: dopamine, epinine, noradrenaline = adrenaline and isoprenaline. The following drugs, in order of potency, were also agonists on this preparation: ergonovine, ergotamine, 6-hydroxydopamine, apomorphine, phenylephrine, norphenylephrine, beta-phenylethylamine, tyramine, D, L-dopa and octopamine. Nialamide increased the response to near-threshold concentrations of dopamine but had no intrinsic activity. Dopamine-induced secretion was depressed by phenoxybenzamine, alpha-flupenthixol, phentolamine, propranolol and dichloroisoprenaline, but only at conce,trations 10- to 1000-fold that of the agonist. Pimozide and spiperone (10(-6) M) augmented the maximum response of dopamine. The tick salivary gland, thus appears to contain one or several receptors differing pharmacologically from mammalian alpha-adrenergic, beta-adrenergic and dopamine receptors.

Animals↗

PubMed1979

Effect of catecholamine-receptor stimulating agents on blood pressure after local application in the nucleus tractus solitarii of the medulla oblongata.

The effect of various catecholamines and alpha-mimetics, given by microinjection in the A2-region of the nucleus tractus solitarii (NTS), on blood pressure was investigated in anesthetized male rats. A dose-dependent decrease of blood pressure and heart rate was induced by adrenaline as the most effective drug, followed by noradrenaline, dopamine, alpha-methylnoradrenaline and octopamine. Ablation of the rostral or caudal part of the NTS, or removal of the area postrema did not diminish the effect of alpha-methylnoradrenaline. Higher doses of noradrenaline and alpha-methylnoradrenaline caused an initial rise of blood pressure, while the blood pressure lowering effect of noradrenaline was diminished, and that of alpha-methylnoradrenaline and dopamine delayed. Isoprenaline and the (+)-stereoisomers of noradrenaline and alpha-methylnoradrenaline were ineffective. The hypotensive effect of dopamine was not prevented by systemic injection of the dopamine beta-hydroxylase inhibitor FLA 63. Prior application of haloperidol, yohimbine and phentolamine antagonized the hypotensive response to dopamine and alpha-methylnoradrenaline. Application of peripherally effective alpha-mimetics into the A2-region had no or little effect, while high doses increased blood pressure. Tyramine and clonidine caused some decrease of blood pressure. Clonidine also decreased blood pressure when it was applied in the area of the locus coeruleus. Application of isoprenaline in the locus coeruleus also decreased blood pressure while in contrast adrenaline, noradrenaline, dopamine and alpha-methylnoradrenaline increased blood pressure. The present data suggest that the catecholaminergic receptors in the A2-region of the NTS differ from the classic vascular alpha-receptor and that the NTS also may contain structures which can antagonize the decrease in blood pressure.

Animals↗

PubMed1983

Sensitivity of compacta neurones in the rat substantia nigra slice to dopamine agonists.

Extracellular recordings were made from neurones in the zona compacta of the substantia nigra in a novel slice preparation in vitro. The pharmacological profile of some dopamine related drugs was assessed by their depressant action on neuronal firing after known concentrations were added to the perfusing media. The most potent drugs were the rigid stable dopamine analogues 2-amino-6,7-dihydroxy-1,2,3,4- tetrahydronapthalene (ADTN) and apomorphine. 2-Amino-5,6-dihydroxy-1,2,3,4- tetrahydronapthalene (5,6-ATN), was less potent than either. Octopamine, Norphenephrine , m- and p-tyramine were all less potent than dopamine. Although noradrenaline was equipotent to dopamine, alpha- and beta-adrenoreceptors were not involved since propranolol and phentolamine were not antagonists, while (-)-sulpiride, haloperidol and alpha-flupentixol were potent antagonists of the dopamine mediated responses.

Animals↗

PubMed1986

Effects of catecholamine and monophenolamine agonists on identifiable giant neurones, sensitive to these amines, of an African giant snail (Achatina fulica Férussac).

The effects of 23 substances proposed as catecholamine (CA) and monophenolamine (MA) agonists were tested on the five CA-sensitive neurones, periodically oscillating neurone (PON), tonically autoactive neurone (TAN), left-visceral multiple spike neurone (1-VMN), dorsal-right pedal autoactive neurone (d-RPeAN) and visceral intermittently firing neurone (VIN), and the three MA-sensitive neurones, frequently autoactive neurone (FAN), dorsal-left pedal large neurone (d-LPeLN) and dorsal-left cerebral distinct neurone (d-LCDN), of an African giant snail (Achatina fulica Férussac). Of these neurones, PON, VIN and d-LPeLN were excited by the most effective catecholamine or monophenolamine, i.e. dopamine, epinine or DL-octopamine, whereas TAN, 1-VMN, d-RPeAN, FAN and d-LCDN were inhibited by the same substances. Of the five CA-sensitive neurones, PON and VIN were markedly excited by ergometrine (effective potency quotients (EPQs) of these substances as compared with the effective potency of the most effective catecholamine or monophenolamine for these neurones: 3.0 for PON, 1.0 for VIN), methylergometrine (EPQs: 3.0 for PON, 0.3 for VIN) and mescaline (EPQs: 0.3 for PON, 1.0 for VIN). These two neurones were excited slightly by DL-metaraminol (EPQs: 0.03 for both neurones) and DL-neosynephrine (EPQs: 0.03 for PON, 0.1 for VIN); VIN was also slightly sensitive to 3-methoxytyramine (EPQ: 0.03). TAN and 1-VMN were inhibited by ergometrine (EPQs: 1.0 for TAN, 0.3 for 1-VMN) and methylergometrine (EPQs: 0.3 for TAN, 0.1 for 1-VMN), whereas d-RPeAN was inhibited slightly only by DL-neosynephrine (EPQ: 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Amines↗

PubMed1994

Inhibition by imidazoline and imidazolidine derivatives of glibenclamide-sensitive K+ currents in Xenopus oocytes.

The effects of imidazoline and imidazolidine derivatives on glibenclamide-sensitive K+ currents induced by the novel K+ channel opener, Y-26763 ((+)-(3S,4R)-4-(N-acetyl-N-benzyloxyamino)-6-cyano-3,4-dihydro-2,2 -dimethyl-2H-1-benzopyran-3-ol), were investigated in voltage-clamped follicle-enclosed Xenopus oocytes. Of 14 imidazoline derivatives and seven imidazolidine derivatives tested, phenotalmine, (-)-cibenzoline, (+)-cibenzoline, alinidine, oxymetazoline, antazoline, midaglizole, xylometazoline, tramazoline and ST91 (2-(2,6-diethylphenylamino)-2-imidazoline hydrochloride) potently suppressed Y-26763-induced K+ currents (IC50 < 80 microM). The compounds which lack an aromatic ring in their structure, 2-methyl-2-imidazole and 2-hydrazino-2-imidazoline, did not affect the K+ currents. Clonidine and idazoxan, which both bind to imidazoline-preferring binding sites with high affinity in various tissues, showed only a small inhibitory effect on Y-26763-induced K+ currents (IC50 780 microM and 955 microM, respectively). The non-imidazoline/non-imidazolidine alpha-adrenoceptor antagonists, WB-4101 (2-(2,6-dimethoxy-phenoxyethyl)-aminomethyl-1,4-benzodioxane hydrochloride), yohimbine and rauwolscine, showed suppressive effects on Y-26763-induced K+ currents (IC50 203 microM, 813 microM and 832 microM, respectively). Octopamine (1 mM), a non-imidazoline/non-imidazolidine alpha-adrenoceptor agonist, was inactive. The results suggest that (1) an aromatic ring or aromatic rings are an essential moiety for imidazoline or imidazolidine derivatives to block glibenclamide-sensitive K+ currents in oocytes, and (2) the K+ current-blocking ability of imidazolines and imidazolidines is related to the alkylation of the benzene ring and the existence of a tertiary amine structure. The K+ current-blocking effects of imidazolines or imidazolidines may not be mediated by alpha-adrenoceptors, at least in follicle-enclosed Xenopus oocytes.

Animals↗