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At least 1,531 records · Page 85Linked to original sources
PubMed1988

5-HT1B receptors are negatively coupled with adenylate cyclase in rat substantia nigra.

We measured the inhibition of forskolin-stimulated adenylate cyclase by 5-hydroxytryptamine (5-HT) and other serotonin agonists in rat substantia nigra homogenates. 5-HT, 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)indole (RU 24969), 5-carboxamidotryptamine (5-CT), 1-(m-trifluoromethyl-phenyl)piperazine (TFMPP) and tryptamine inhibited forskolin-stimulated adenylate cyclase with EC50 of 67, 40, 83, 100 and 200 nM respectively. 8-Hydroxydipropylaminotetralin (8-OH-DPAT) and ipsapirone, both 5-HT1A-selective drugs, were respectively weak and ineffective to inhibit forskolin-stimulated adenylate cyclase. CGS 120 66B was almost as potent (EC50 = 100 nM) as 5-HT to inhibit the forskolin-stimulated adenylate cyclase in rat substantia nigra homogenates whereas this preferential 5-HT1B agonist was 100 times less potent than 5-HT in hippocampus guinea pig homogenates. Spiroperidol, mesulergine and ketanserin, which are potent 5-HT1A, 5-HT1C and 5-HT2 antagonists respectively, were unable to reverse the 5-HT-mediated inhibition of forskolin-stimulated adenylate cyclase whereas the beta-adrenoceptor antagonists, (+/-)-cyanopindolol and (+/-)-propranolol or metergoline, fully reversed the 5-HT effect with calculated Ki of 34 +/- 18, 82 +/- 19 and 248 +/- 47 nM, respectively. The pharmacological profile of the 5-HT receptor mediating the inhibition of adenylate cyclase in substantia nigra indicates that this receptor probably corresponds to 5-HT1B binding sites. Our conclusion is that, in addition to the 5-HT1A receptor, the 5-HT1B receptor is also negatively coupled to adenylate cyclase.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1990

5-HT1 receptor agonists reduce the Ca+ component of sensory neuron action potentials.

Serotonin (5-HT) agonists, selective for 5-HT1, 5-HT2 or 5-HT3 receptor subtypes, were tested for their ability to mimic 5-HT in narrowing the tetraethylammonium-induced calcium-dependent plateau of action potentials recorded from frog sensory neurons. 5-Carboxamidotryptamine, 5-HT, alpha-methyl 5-HT and 5-methoxy-tryptamine possessed full agonist activity, with EC50S of 19 nM, 210 nM, 3.7 microM and 1.7 microM, respectively. 2-Methyl 5-HT was inactive. This agonist profile indicates that the calcium-dependent plateau in these sensory somata is modulated by a 5-HT1-like receptor.

5-Methoxytryptamine↗
PubMed1990

Constriction of porcine arteriovenous anastomoses by indorenate is unrelated to 5-HT1A, 5-HT1B, 5-HT1C or 5-HT1D receptor subtypes.

The study concerns the effects of indorenate, a tryptamine derivative with antihypertensive properties as well as high affinity for the 5-HT1A binding site, on carotid haemodynamics in anaesthetized pigs. Intracarotid infusions of indorenate (0.3, 1.0, 3.0 and 10.0 micrograms.kg-1.min-1 for 10 min each) caused dose-related decreases in total common carotid artery blood flow due almost exclusively to a reduction in arteriovenous anastomotic flow. These effects of indorenate were not appreciably modified after treatment with the 5-HT2 receptor antagonist ketanserin (0.5 mg.kg-1 i.a.), but were markedly reduced after treatment with methiothepin (1.0 mg.kg-1 i.a.), which antagonizes not only 5-HT2 receptors, but also the putative 5-HT1A, 5-HT1B 5-HT1C and 5-HT1D subtypes of 5-HT1-like receptors. Nonetheless, metergoline (1 mg.kg-1 i.a.), a drug with higher affinity than methiothepin for the above 5-HT1 receptor subtypes, failed to significantly modify the responses to indorenate. It is therefore concluded that, like 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole (RU 24969), indorenate reduces both total common carotid and cephalic arteriovenous anastomotic blood flow in the pig by stimulating 5-HT1-like receptors; these receptors, however, do not seem to correspond to either 5-HT1A, 5-HT1B, 5-HT1C or 5-HT1D binding sites.

5-Methoxytryptamine↗
PubMed1991

A peripheral 5-HT1D-like receptor involved in serotonergic induced hindlimb scratching in rats.

The pharmacological characteristics of hindlimb scratching induced by serotonergic compounds were studied. We conclude that hindlimb scratching induced by serotonergic compounds is mediated by a serotonin1D (5-HT1D) or 5-HT1D-like receptor outside the blood-brain barrier because hindlimb scratching could be induced by s.c. injection of 5-methoxytryptamine (5-MeOT), 5-carboxamidotryptamine (5-CT), bufotenine, 5-hydroxytryptamine (5-HT) and tryptamine. These compounds have high affinity for 5-HT1A and 5-HT1D receptors. The 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), the 5-HT1C receptor agonist MK 212, and the mixed 5-HT1C/5-HT2 receptor agonists (dl)-1-(2,5 dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and quipazine did not induce hindlimb scratching. Rather, the latter compounds attenuated 5-MeOT-induced hindlimb scratching. The 5-HT releasing compounds fenfluramine and p-chloroamphetamine (PCA) inhibited whereas the 5-HT re-uptake inhibitors fluvoxamine and indalpine potentiated 5-MeOT-induced hindlimb scratching. 5-MeOT-induced hindlimb scratching could be inhibited dose dependently by the alpha 2-adrenoceptor blockers yohimbine and rauwolsince, which also have high affinity for 5-HT1D receptors, whereas the alpha 2-adrenoceptor blocker piperoxan only weakly counteracted hindlimb scratching. Haloperidol, apomorphine, morphine, clonidine and methiothepin strongly attenuated hindlimb scratching, atropine, naloxone and ICS 205930 attenuated it weakly whereas domperidone, methylatropine and mepyramine were inactive in doses up to 10 mg/kg. Hindlimb scratching induced by 5-MeOT was potentiated by the 5-HT receptor antagonists metergoline, methysergide, mesulergine, mianserin, ritanserin and xylamidine. Hindlimb scratching was not induced by i.c.v. injection of 5-MeOT.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Methoxytryptamine↗
PubMed1991

The effects of 8-OH-DPAT on medullary 5-HT neurons and sympathetic activity in baroreceptor-denervated animals.

The effects of the 5HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on medullary 5-hydroxy-tryptamine (5-HT) neuronal firing and inferior cardiac sympathetic nerve activity were simultaneously determined in baroreceptor-denervated cats. 5-HT neuronal firing was inhibited by 50% at a 1 microgram/kg i.v. dose of 8-OH-DPAT in the baroreceptor-denervated animal. Unit firing was completely inhibited by a 3 microgram/kg dose. In contrast, 8-OH-DPAT inhibited inferior cardiac nerve activity between 10 and 100 micrograms/kg i.v. A similar relationship between the 8-OH-DPAT-induced inhibition of 5-HT unit activity and sympathetic nerve activity was observed in sham-operated control animals. These data suggest that the sympatholytic effects of 8-OH-DPAT cannot be explained on the basis of an autoreceptor effect of the drug.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Noradrenergic mediation of spinal antinociception by 5-hydroxytryptamine: characterization of receptor subtypes.

The present study examined the involvement of spinal noradrenergic mechanisms in spinal antinociception by the 5-hydroxy-tryptamine (5-HT) receptor-selective agonists CGS 12066B (5-HT1B; 7-trifluoromethyl-4(4-methyl-1-piperazinyl)-pyrrolo[1,2-a]quinoxaline), TFMPP (5-HT1C; M-trifluoromethylphenyl-piperazine) and DOI (5-HT2; 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane) using the rat hot plate test. Effects of alpha-adrenoreceptor antagonists (phentolamine, yohimbine), the adrenergic neurotoxin 6-hydroxydopamine, and the selective noradrenergic uptake blocker desipramine were determined. CGS 12066B, TFMPP and DOI produced dose-related antinociception. The antinociceptive effect of each agent was reduced by pretreatment with both phentolamine and yohimbine (15-60 micrograms). Pretreatment with 6-hydroxydopamine (100 micrograms, intrathecal) for 7-10 days, which reduced spinal cord levels of noradrenaline by 87%, inhibited the action of TFMPP (and 5-HT), but not CGS 12066B or DOI. Pretreatment with desipramine (25 mg/kg, systemic) potentiated the action of TFMPP but not CGS 12066B or DOI (or 2-methyl-5-HT). These results suggest that antinociception by TFMPP is dependent on release of endogenous noradrenaline from the spinal cord, while that produced by CGS 12066B and DOI is not. As TFMPP exhibits a close similarity to 5-HT in these experiments, the 5-HT receptor subtype being activated to induce noradrenaline release may either be a 5-HT1C or a 5-HT1S subtype. Other mechanisms account for the observed blockade of the action of CGS 12066B and DOI by alpha-adrenoreceptor antagonists.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1994

Effect of long-term administration of antidepressant drugs on the 5-HT3 receptors that enhance the electrically evoked release of [3H]noradrenaline in the rat hippocampus.

The present study investigated the effects of various classes of antidepressant drugs (10 mg/kg per day, s.c. during 21 days) on the electrically evoked release of [3H]noradrenaline and on its modulation by the 5-HT3 receptor agonist 2-methyl-5-hydroxy-tryptamine (2-methyl-5-HT) using preloaded rat hippocampal slices. Treatments with either fluoxetine, a selective serotonin (5-HT) reuptake inhibitor, or moclobemide, a reversible type A monoamine oxidase inhibitor, increased the evoked release of [3H]noradrenaline. These two antidepressant treatments did not change, however, the magnitude of the enhancing effect of 2-methyl-5-HT on the electrically evoked release of [3H]noradrenaline. Desipramine produced a much larger increase of the electrically evoked release of [3H]noradrenaline than fluoxetine or moclobemide, and desensitized the 5-HT3 receptors that modulate this release. Trimipramine, which like desipramine has a tricyclic structure but does not block the reuptake of noradrenaline or that of 5-HT, did not increase the evoked release of [3H]noradrenaline and did not desensitize the 5-HT3 receptors that enhance the release of [3H]noradrenaline. Maprotiline, a selective noradrenaline reuptake inhibitor, did not produce the same changes as desipramine, but maprotiline inhibited noradrenaline reuptake to a lesser extent (50%) than desipramine (80%). These results suggest that the high potency noradrenaline reuptake blocker desipramine desensitizes 5-HT3 receptors modulating [3H]noradrenaline release, but that this effect is not common to all antidepressant drugs.

Animals↗
PubMed1995

R(+)-8-OH-DPAT, a 5-HT1A receptor agonist, inhibits amphetamine-induced dopamine release in rat striatum and nucleus accumbens.

Systemic administration of R(+)-8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin), a selective serotonin (5-hydroxy-tryptamine, 5-HT)1A receptor agonist (25, 50, and 100 mu g/kg s.c.), administered 30 min prior to d-amphetamine, significantly inhibited the d-amphetamine sulfate (1.0 mg/kg s.c.)-induced increase in extracellular dopamine levels in the striatum and nucleus accumbens of freely moving rats, as determined by in vivo microdialysis. The ability of R(+)-8-OH-DPAT (50 mu g/kg s.c.) to inhibit d-amphetamine sulfate (1.0 mg/kg s.c.)-induced increase in extracellular dopamine levels was abolished by WAY 100,635 (n-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-n-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride), a selective 5-HT1A receptor antagonist (100 mu g/kg s.c.), administered 5 min prior to R(+)-8-OH-DPAT in both regions. These results indicate that the 5-HT1A receptor may exert an inhibitory effect on amphetamine-induced dopamine release.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1986

Regulation of the activity of histamine-N-methyltransferase from guinea pig skin by biogenic amines.

Histamine-N-methyltransferase, a major histamine-degrading enzyme in the skin, was purified from guinea pig skin about 150-fold. The enzymological characteristics including pH optimum, Km values for substrates, and molecular weight were almost consistent with those reported in the brain. Regulatory mechanism of the enzyme activity by biogenic amines was investigated using the purified specimen. Serotonin, tryptamine, and 5-methoxytryptamine intensely inhibited the activity while tryptophan, melatonin, N-acetylserotonin, tryptophol, and 5-hydroxyindole acetic acid had no significant effects. Dopamine, tyramine, 3-methyltyramine, and phenylethylamine also inhibited the activity while no particular effects were obtained by adrenaline, noradrenaline, tyrosine, and DOPA. Spermidine and cadaverine caused significant but weaker inhibition. These amines acted competitively with respect to histamine, although varying manners were observed with respect to S-adenosyl-L-methionine. From these results, it was concluded that the enzyme activity was inhibited by such compounds in which a certain chemical structure, CH2-CH2-NH2 group neighboring the hydrophobic group, was contained. A possible mechanism of inhibition by the amines is postulated, and possible roles of such compounds in the inflammation by impairing the histamine metabolism is discussed.

Animals↗
PubMed1987

Harmala alkaloids and related beta-carbolines: a myoclonic model and antimyoclonic drugs.

The neuropharmacologic profile of intraperitoneally injected harmala alkaloids and related beta-carbolines was evaluated in the rat. All drugs induced central effects (convulsions, catalepsy, or altered startle), but only harmaline and harmine were tremorogenic at low doses. Methoxylation of the carboline 7 position was requisite for this effect. Coadministration of harmaline (but not harmine) and 5-hydroxytryptophan (tryptamine or m-chlorophenyl-piperazine) induced a lethal convulsive myoclonic syndrome which could not be evoked by either drug separately. Compared with the myoclonic-serotonergic syndrome evoked by 5-hydroxytryptophan in rats with 5.7-dihydroxytryptamine lesions, harmaline+5-hydroxytryptophan-treated rats displayed more continuous and greater axial myoclonic jerks and some postural differences. Clorgyline or tranylcypromine but not pargyline could be substituted for harmaline. The harmaline syndrome was blocked by the benzodiazepine agonists, physostigmine and verapamil. The harmaline+5-hydroxytryptophan syndrome was blocked by drugs acting at benzodiazepine receptors (CL 218,872 greater than ethyl-beta-carboline-3-carboxylate, clonazepam, diazepam, Ro 15-1788, pentobarbital), and baclofen. Naloxone, benztropine, quipazine, and apomorphine had partial effects, and calcium channel blockers prevented death but did not prevent convulsions. 5-Hydroxytryptamine antagonists were poor blockers, although cyproheptadine and ketanserin significantly reduced mortality. Phenobarbital was more effective than other anticonvulsants. Lesion studies suggested a role for monoaminergic neurons and the inferior olive in the expression of the harmaline+5-hydroxytryptophan syndrome. These data describe a complex convulsive myoclonic syndrome that is behaviorally related to but pharmacologically distinct from the serotonin syndrome, which may be useful in studying serotonergic-benzodiazepine interactions in the pathophysiology of myoclonus.

5-Hydroxytryptophan↗
PubMed1986

Lack of inhibition of thrombin-induced rise in intracellular Ca2+ levels and 5-hydroxytryptamine secretion by 1-oleoyl-2-acetylglycerol in human platelets.

The effect of 1-oleoyl-2-acetylglycerol (OAG) on the thrombin-induced rise in intracellular Ca2+ levels ([Ca2+]i) and 5-hydroxy[14C]tryptamine ([14C]5HT) secretion was studied. In washed human platelets prelabelled with [14C]5HT and quin 2, OAG (10-50 micrograms/ml) induced no significant aggregation, [14C]5HT secretion or rise in [Ca2+]i in the presence or absence of fibrinogen. However, addition of OAG (10-50 micrograms/ml) 10 s to 5 min before or 10-60 s after addition of threshold concentrations of thrombin (less than 0.03 U/ml) resulted in a significant potentiation of aggregation and [14C]5HT secretion without any effect on the thrombin-induced rise in [Ca2+]i. Both EGTA, which abolished the latter and creatine phosphate/creatine phosphokinase, the ADP scavenger, totally inhibited the aggregation but only partially reduced [14C]5HT secretion in response to thrombin plus OAG. At higher concentrations of thrombin, neither the rise in [Ca2+]i nor the extent of [14C]5HT secretion was significantly altered by OAG addition. The results demonstrate that, unlike phorbol esters, OAG has no inhibitory effect on thrombin-induced [Ca2+]i mobilisation but can synergize with low concentrations of thrombin in potentiating [14C]5HT secretion even at basal [Ca2+]i.

Blood Platelets↗
PubMed1988

The cDNA clone for strictosidine synthase from Rauvolfia serpentina. DNA sequence determination and expression in Escherichia coli.

The cDNA clone for strictosidine synthase, the enzyme which catalyzes the stereospecific condensation of tryptamine with secologanin to form the key intermediate in indole alkaloid biosynthesis, strictosidine, has been identified with a synthetic oligodeoxynucleotide hybridization probe in a lambda gt11 cDNA library of cultured cells of Rauvolfia serpentina. The DNA has been sequenced, revealing an open reading frame of 1032 base pairs encoding 344 amino acids. The sequence of 60 nucleotides in the 5'-flanking region has been determined by primer extension analysis. The encoded protein has been expressed in E. coli DH5 as detected by immunoblotting of protein extracts with antibodies raised against the native enzyme.

Amino Acid Sequence↗
PubMed1989

Expression of enzymatically active cloned strictosidine synthase from the higher plant Rauvolfia serpentina in Escherichia coli.

The cDNA for strictosidine synthase, the enzyme catalyzing the stereospecific condensation of tryptamine with secologanin producing strictosidine, the key intermediate in indole alkaloid biosynthesis, has been expressed in an enzymatically active form in Escherichia coli. The cDNA trimmed of its 3'- and 5'-flanking regions was inserted into the vector pKK223-3 by addition of a synthetic adapter containing the ribosome binding site derived from the beta-galactosidase gene. Strictosidine synthase activity (138 nkat.l-1) could be measured in both whole bacteria and in bacterial protein extracts. Strictosidine synthase represents the first enzyme of plant secondary metabolism to be actively expressed in a microorganism.

Carbon-Nitrogen Lyases↗
PubMed1995

A primordial dopamine D1-like adenylyl cyclase-linked receptor from Drosophila melanogaster displaying poor affinity for benzazepines.

We report here the isolation from Drosophila melanogaster of a 2.0 kb cDNA clone encoding a 385 amino acid protein (dDA1) displaying, within putative transmembrane domains, highest amino acid sequence homology (49-53%) to members of the vertebrate dopamine D1-like receptor family. When expressed in either Sf9 or COS-7 cells, dDA1 did not bind the specific D1-like receptor antagonist [3H]SCH-23390 or numerous other dopaminergic, adrenergic or serotoninergic ligands with high affinity. However, like vertebrate dopamine D1-like receptors, dDA1 stimulated the accumulation of cAMP in response to DA (EC50 approximately 300 nM) and 6,7-ADTN (EC50 approximately 500 nM). The dopaminergic rank order of potency (DA > NE >> 5-HT) and the lack of stimulation by other possible neurotransmitters (octopamine, tyramine, tryptamine) or DA metabolites (e.g. N-acetyl dopamine) found in Drosophila suggests that this receptor functionally belongs to the dopamine D1-like subfamily. Benzazepines, which characteristically bind to vertebrate dopamine D1-like receptors with high affinity, were relatively poor in stimulating (SKF-38393, SKF-82526; EC50 > 10 microM) dDA1-mediated accumulation of cAMP. Of the numerous compounds tested, a few dopaminergic antagonists inhibited DA-stimulated production of cAMP in a concentration-dependent manner, albeit with considerably reduced affinity, and with the rank order of potency: (+)-butaclamol(Kb approximately 125nM) > SCH-23390(Kb approximately 230nM) > alpha-flupenthixol (Kb approximately 400 nM) > chlorpromazine > or = spiperone (Kb approximately 680 nM) > or = clozapine. In situ hybridization revealed that dDA1 receptor mRNA is expressed as a maternal transcript, and at later blastoderm stages is restricted to apical regions of the cortical peripheral cytoplasm. The generation of inter-species D1 receptor chimeras may help to identify those particular sequence-specific motifs or amino acid residues conferring high affinity benzaepine receptor interactions.

Adenylyl Cyclases↗
PubMed1995

Isolation and characterization of an arylalkylamine N-acetyltransferase from Drosophila melanogaster.

The enzyme arylalkylamine N-acetyltransferase (aaNAT) catalyzes the rate-limiting step in melatonin formation in the vertebrate pineal gland. Numerous attempts to purify this highly unstable enzyme from vertebrates have been unsuccessful. Here, we report the purification of an aaNAT enzyme from Drosophila melanogaster, using a radioenzymatic activity assay and column chromatography. The isolated 29.5-kDa protein acetylates tryptamine, dopamine and serotonin with affinities of 0.89 to 0.97 mM, respectively. This suggests that the identified aaNAT may be involved in melatonin synthesis and sclerotization as well as in neurotransmitter catabolism in insects.

Amino Acid Sequence↗
PubMed1985

Effect on human platelets of catecholamines at levels achieved in the circulation.

Epinephrine at concentrations varying between 3.3 and 12.5 nM had no effect on blood platelets when added alone, but augmented the in vitro platelet response to collagen and thrombin. Both aggregation and secretion responses were enhanced. Norepinephrine produced similar effects but was 50-60% less active than epinephrine. The minimum concentration of epinephrine or norepinephrine to achieve potentiation of platelet responses was even lower in the presence of 5-hydroxy- tryptamine. In contrast to the effects observed with higher concentrations of catecholamines, the synergistic interaction of these low concentrations of catecholamines with other agonists was not transient. The augmented response to catecholamines was mediated by platelet alpha 2-adrenoceptors. The response was inhibited by aspirin indicating that metabolism of arachidonic acid contributes to the synergy between low concentrations of catecholamines and other agonists. These studies show that the levels of the hormones epinephrine and norepinephrine obtained in circulating blood in humans, can be sufficient to enhance platelet responses. The action of catecholamines on platelets may be important in hemostasis and could provide an explanation for the association between certain risk factors and cardiovascular disease.

Adenosine Diphosphate↗
PubMed1991

High-performance metal chelate affinity chromatography of cytochromes P-450 using Chelating Superose.

High-performance metal chelate affinity chromatography [immobilized metal ion affinity chromatography (IMAC)] using Chelating Superose (iminodiacetic acid adsorbent) was investigated for its suitability in purifying phenobarbital-induced rat liver microsomal cytochrome P-450 isozymes (P450) and optimized for preparative purposes. Starting with an 8-aminooctyl-Sepharose fraction of partially purified P450, it was found that only Ni(2+)- and Cu(2+)-charged columns could bind P450. No binding was ever observed when Zn2+, Co2+, Mn2+, Cd2+, Fe3+, Fe2+ or Tl3+ ions were employed. Of eight commonly used elution buffers, imidazole and tryptamine were found to cause some denaturation of P450. For desorption of proteins bound to Ni(2+)-charged columns, the following order of decreasing elution buffer strength was determined: cysteine approximately histidine greater than glycine greater than histamine greater than tryptophan greater than ammonium chloride. During protein desorption with some of these buffers, metal ions were found to bleed from the gel, resulting in P450 denaturation. This could be eliminated by prebleeding the charged columns prior to sample application and had an effect on product recovery and homogeneity. Ni2+ and glycine were chosen as a standard for further optimization involving sample adsorption conditions as influenced by equilibration buffer, detergent, load capacity and flow, gradient and temperature conditions. In this way, potassium phosphate (pH 7.75) and 0.4% Emulgen 911 were used to equilibrate a 1.6-ml column and purify 20-50 nmol of P450 (5-15 mg of protein) within 15 min. One gradient fraction consisted of a single sodium dodecyl sulphate-polyacrylamide gel electrophoresis band as judged by silver staining and represented about 25% of the total P450 applied to the column; total recoveries were usually more than 80%. Comparison with the molecular weights and spectral, catalytic and immunological properties of P450 forms isolated according to established procedures indicated that the form isolated here using Chelating Superose comprises mainly P450 2B1 (PB-B). A method is described for fully automated, programmable column regeneration and sample runs.

Animals↗
PubMed1992

Improvement of extraction procedure for biogenic amines in foods and their high-performance liquid chromatographic determination.

A high-performance liquid chromatography method is described for the simultaneous determination of the biogenic amines tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine in cheese. The optimization of the procedure for the extraction of amines from the matrix is described. The separation of dansyl derivatives of the amines was achieved by reversed-phase liquid chromatography with gradient elution, followed by UV detection at 254 nm. The mobile phase was acetonitrile-0.01 M phosphate buffer (pH 7)-water. Under these conditions, rapid elution of the amines in less than 13 min was obtained. Validation of the method included calibration experiments, addition of standard amines for the determination of amine recoveries and repeatability tests.

Biogenic Amines↗