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At least 19 recordsLinked to original sources
PubMed1992

Effects of the stereochemical orientation of phenethylamines and imidazolines on alpha-adrenergic receptor-mediated DNA synthesis in primary cultured rat hepatocytes.

The hepatic alpha 1-adrenergic receptor mediates a variety of hepatic functions including respiration, glycogenolysis, gluconeogenesis, and growth. We have utilized a rat primary hepatocyte culture system to show that the alpha 1-adrenergic receptor can be activated in a stereoselective manner by a series of phenethylamines and catecholimidazolines resulting in the stimulation of DNA synthesis as determined by [3H]thymidine incorporation. The phenethylamines adhered to the Easson-Stedman hypothesis with a rank order of potency of (-)-(R)-norepinephrine (NE) greater than (+)-(S)-NE greater than the desoxy analog dopamine (DA) for the stimulation of DNA synthesis. However, the 2-substituted catecholimidazolines did not follow this trend and demonstrated an order of potency of the desoxy analog 3,4-dihydroxybenzyl imidazoline (DHT) greater than or equal to (-)-(R)-2-(3,4,alpha-trihydroxybenzyl)imidazoline (TBI) greater than (+)-(S)-TBI. 4-Substituted catecholimidazolines were less potent as inducers of DNA synthesis than the corresponding 2-substituted analogs with an order of potency of (+)-(R)-4-(3,4-dihydroxybenzyl)imidazoline (DBI) greater than (+,-)-(R,S)-DBI greater than (-)-(S)-DBI. When the beta-hydroxyl moiety of NE is replaced with an amino group as in 3,4-dihydroxyphenylethylenediamine, the isomers are less active than the beta-hydroxylated analogs and also demonstrate no stereoselectivity for the stimulation of DNA synthesis. These results demonstrate that the hepatic alpha 1-adrenergic receptor can recognize various isomeric forms of these compounds and that hepatocellular growth can be modulated in a stereoselective manner by phenethylamines and imidazolines.

Animals↗
PubMed1992

Inhibition of in vitro prostaglandin and leukotriene biosyntheses by cinnamoyl-beta-phenethylamine and N-acyldopamine derivatives.

N-trans- and N-cis-Feruloyltyramines were isolated as the inhibitors of in vitro prostaglandin (PG) synthesis from an Indonesian medicinal plant, Ipomoea aquatica (Convolvulaceae). In order to clarify structure activity relationships, cinnamoyl-beta-phenethylamines with possible combinations of naturally occurring cinnamic acids and beta-phenethylamines were synthesized and tested for their inhibitory activities against PG synthetase and arachidonate 5-lipoxygenase. The compounds containing catechol groups such as N-caffeoyl-beta-phenethylamine (CaP) showed higher inhibitory effects on PG synthetase. The catechol group was found to be essential for the inhibition of arachidonate 5-lipoxygenase. The investigation of concentration dependent effects on PG biosynthesis revealed that CaP enhanced PG biosynthesis at a lower concentration range, whereas it inhibited the reaction at a higher concentration. The effects of CaP on each reaction step were investigated with purified PG endoperoxide synthase and microsomal PG synthetase. CaP inhibited the cyclooxygenase reaction, while it enhanced the hydroperoxidase reaction. N-Acyldopamines which contain catechol and lipophylic group were synthesized from dopamine and fatty acids to test their inhibitory effects on arachidonate 5-lipoxygenase. N-Linoleoyldopamine was the most active compound and its IC50 value was 2.3 nM in our assay system, in which an IC50 value of AA 861, a specific inhibitor of 5-lipoxygenase, was 8 nM.

Cinnamates↗
PubMed1977

Structure-anorectic activity relationships in substituted phenethylamines.

A series of phenylisopropylamine derivatives are compared with the correspondent beta-methoxy- and beta-hydroxy-phenethylamine compounds. Unlike amphetamine, the beta-methoxy phenethylamine has no anorectic activity. This property appears only with the introduction of a CF3 group on the benzene nucleus. The racemic N-alkyl derivatives are more active than the racemic or even the levorotatory N-benzyl compound. The beta-hydroxy-phenethylamines are devoid of anorectic activity.

Animals↗
PubMedDate not supplied

Cactus alkaloids. XXXI. beta-Phenethylamines and tetrahydroisoquinolines from the Mexican cactus dolichothele uberiformis.

A total of ten alkaloids have been identified in extracts of a Mexican cactus, Dolichothele uberiformis (Zucc.) Br. and R. The data provide documentation for the presence of (--)-synephrine, (--)-longimammine, N-methyl-3,4-dimethoxy-beta-phenethylamine, N-methyl-4-methoxy-beta-phenethylamine, (--y-normacromerine, N-methyltryramine, hordenine, longimammatine, and the first reported isolation of (--)-N,N-dimethyl-beta-hydroxy-beta-phenethylamine (ubine) from a natural source. Spectral data support the identification of another new alkaloid (uberine) as 5-methoxy-7-hydroxy-2-methyl-1,2,3,4-tetrahydroisoquinoline.

Desert Climate↗
PubMed1978

Structural and steric requirements for beta-phenethylamines as agonists of the noradrenergic cyclic AMP generating system in the rat limbic forebrain.

The present studies were undertaken to assess the structural and steric requirements for beta-phenethylamines as agonists of the noradrenergic cyclic AMP generating system in slices of the rat limbic forebrain. Significant agonist activity of beta-phenethylamines requires a beta-3,4-dihydroxyphenethylamine with a beta-hydroxyl group in the R configuration. Thus, dopamine did not stimulate the system at concentrations up to 10(-3) M. Moreover, beta-hydroxyphenethylamines without a 3,4-catechol group (octopamine, phenylephrine, p-hydroxynorephedrine, metaraminol and methoxamine) - though exerting alpha-agonist activity in peripheral tissues - lack agonist activity in this particular cyclic AMP generating system. The effects of (R)-norepinephrine and (R)-isoproterenol at maximal concentrations were not additive. The results lend further support to the view that the cyclic AMP generating system in slices of the limbic forebrain is part of a norepinephrine receptor coupled adenylate cyclase system with a subpopulation of receptors that are beta in nature.

Animals↗
PubMed1976

Interactions of nigrostriate synaptic transmission, iontophoretic O-methylated phenethylamines, dopamine, apomorphine and acetylcholine.

Recordings were made from, and drugs applied to, neurons in the caudate nucleus of unanesthetized cats, using multibarrel micropipette electrodes. The substantia nigra was stimulated by sterotactically placed electrodes. Three O-methylated derivatives of dopamine, meta-methoxyphenethylamine (m-MPEA), para-methosy-phenethylamine (p-MPEA) and 3,4-demethoxyphenethylamine (DIMPEA), inhibited most, excited a few, and had no detectable effect on a substantial number of the cells upon which they were tested. A statistically significant correlation was found between the effects of dopamine (DA) and the three O-methylated derivatives on the same populations of cells. Iontophoretic release of the O-methylated derivatives could not prevent the actions of DA, nor could it block synaptically mediated effects of the nigrostriate pathway. It is concluded that the three O-methylated products are partial agonists of DA. The findings are difficult to reconcile with the suggestion that the experimental parkinsonian-like symptoms caused by O-methylated phenethylamines are the consequence of blockade of dopaminergic synapses. No correlation, negative or positive, was found between the effects of DA and of acetylcholine (ACh). The findings do not support the theory that balanced sets of antagonistic synapses, one dopaminergic, the other cholinervic, operate upon individual neurons in the caudate nucleus. Apomorphine and dopamine were shown to have similar effects on a substantial number of neurons, even though the onset and offset of the effect of apomorphine were slower than those of DA. This observation agrees with the suggestion that some of the central effects of apomorphine are due to an action at dopaminoceptive receptor sites.

Acetylcholine↗
PubMed1975

Centrally active phenethylamines.

The two-carbon homologs of two potent psychotomimetic agents are described. Unlike the parent isopropylamine compounds (4-methyl-2,5-dimethoxyamphetamine, DOM, STP; and 4-bromo-2,5-dimethoxyamphetamine, PBR, 4-BR) these phenethylamines lead to an intoxication state which is, in normal subjects, of short duration and of greatly increased sensory enhancement, but which does not superimpose hallucinogenesis. These two phenethylamines, 4-methyl-2,5-dimethoxyphenethylamine (II) and 4-bromo-2,5-dimethoxyphenethylamine (III), are active in man at oral levels of 0.1 to 0.2 mg/Kg, approximately one tenth the potency of their three-carbon counterparts.

Adult↗
PubMed1978

Single dose and cross tolerance studies of beta-phenethylamine, d-amphetamine and LSD in the chronic spinal dog.

The effects of beta-phenethylamine (PEA), d-amphetamine and LSD were studied on spinal reflexes, autonomic signs, and behavior in the non-tolerant and LSD tolerant (30 microgram/kg/day) chronic spinal dog. LSD (10 microgram/kg) facilitated the flexor reflex, produced the stepping reflex, increased respiration, pulse rate and temperature, slightly dilated pupils and produced whining, tracking and restlessness. Direct tolerance developed to all of these effects except temperature. PEA (0.8 mg/kg/min infused for 12 min) and amphetamine (3.2 mg/kg) facilitated the flexor reflex, increased respiration, temperature and the skin twitch reflex latency, caused a marked mydriasis, retracted the nictitating membrane and produced restlessness and stereotypic head movements. PEA but not amphetamine elicited stepping, and only amphetamine consistently slowed heart rate. No cross tolerance to the physiologic or behavioral effects of amphetamine was observed. Partial tolerance developed only to the actions of PEA on the stepping reflex and the nictitating membrane. The single dose effects and the lack of cross tolerance to amphetamine and PEA suggest modes of action different from LSD. PEA has some actions which differ from those of amphetamine.

Amphetamines↗
PubMed1977

Characteristics of beta-phenethylamine self-administration by dog.

Phenethylamine (PEA), a biologically active amine found in the brain, maintained intravenous self-administration behavior by dogs previously trained to respond for amphetamine. Systematic changes in the unit dose of PEA (1.5 to 6.0 mg/kg/infusion) were negatively related to the number of infusions (91.3 to 29.5, respectively) per 4hr session. The mean intake of PEA was 165 mg/kg/session. Pretreatment with chlorpromazine (0.5 to 2.0 mg/kg, IV, 30 min prior to the session) produced a dose-dependent increase in the number of self-administered PEA infusions. However, there were no changes in responding for PEA following pretreatment with either the dopaminergic antagonist pimozide (5 to 40 micrograms/kg, IV, 30 min prior to the session) or the adrenergic antagonist phenoxybenzamine (1 to 8 mg/kg, IV, 30 min prior to the session). These data suggest that the reinforcing properties of PEA are not dependent on either a dopaminergic or adrenergic system.

Animals↗
PubMedDate not supplied

The detection, identification and measurement of indole, tryptamine and 2-phenethylamine in putrefying human tissue.

Indole, tryptamine and 2-phenethylamine are putrefactive products which may be found in decaying human tissue. They may be identified by the data given found in decaying human tissue. They may be identified by the data given for infrared and ultraviolet spectrometry, fluorometry, thin layer and gas chromatography and mass spectrometry. Quantitative studies may be made using the gas chromatography method described. The rate of formation is affected by temperature and preservatives and may be prevented if necessary by the use of sodium fluoride. No relationship between the production of these materials (and alcohol) and time since the post-mortem examination could be established. The post-mortem examinations took place within 24 hours of death.

Ethanol↗
PubMed1975

Correlation of psychotomimetic activity of phenethylamines and amphetamines with 1-octanol-water partition coefficients.

In an attempt to relate the hallucinogenic potencies in man of some biologically important amphetamines and phenethylamines, the 1-octanol-water partition coefficients for 11 amphetamines were determined. Using these values and published Hansch pi constants, the log P for 17 additional amines was estimated. It was found that lipophilicity, as measured by the log of the partition coefficient, may be a significant determinant of the level of hallucinogenic potency. The study also suggests that an ideal log P value for psychotomimetric activity in man may be from 2.89 to 3.72.

Amphetamines↗
PubMed1976

Ultrastructural cytochemistry of p-N,N-dimethylamino-beta-phenethylamine (DAPA) oxidation reactions.

The ultracytochemical localization of amine oxidase (AO) activity is demonstrated with a new substrate, p-N,N-dimethylamino-beta-phenethylamine (DAPA). DAPA was designed to yield a stronger reducing agent on oxidation by monoamine oxidase (MAO) than is obtained from the MAO substrate, tryptamine, upon oxidation. Thus MAO and possibly other oxidase(s) can be demonstrated with DAPA and the tetrazolium salt, 2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl) tetrazolium chloride (BSPT). The latter is a nonosmiophilic tetrazolium salt which is reduced to an osmiophilic formazan. In addition, DAPA itself demonstrates AO activity ultracytochemically with and without BSPT. We speculate that either oxidative polymerization of DAPA or Schiff's base formation with protein after aldehyde formation is responsible for the latter reaction, which is made permanent for ultracytochemical localization by osmication at a later step. DAPA oxidation reaction products are demonstrated in guinea pig kidney, specifically in the endoplasmic reticulum, nuclear envelope and mitochondrial outer compartments and cristae. Differences in reaction product characteristics and localization in relation to formaldehyde fixation and the localization of reaction product in mitochondrial cristae, as well as outer compartments, suggest that DAPA oxidation is mediated through one or more MAOs and possible other oxidases.

Animals↗
PubMed1976

Ultrastructural cytochemistry of p-N,N-dimethylamino-beta-phenethylamine (DAPA) oxidation reactions. "activation" and inhibition studies.

The oxidation of p-N,N-dimethylamino-beta-phenethylamine (DAPA) by amine oxidase(s) (AO), i.e., diamine oxidase (DAO), monoamine oxidase (MAO) and/or possibly other oxidases, has been previously demonstrated. This study reports the results of variations in fixation procedures and the incorporation of a series of possible "activators" and inhibitors into the DAPA oxidase (DAPAO) and DAPAO-BSPT [2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl) tetrazolium chloride] reaction media in an attempt to elucidate the oxidase(s) involved. Results of these studies are indicative of at least two different oxidases acting preferentially on one or the other of the two systems. The presence of MAO, especially in unfixed tissue, and DAO, especially in fixed tissue, is denoted and that of other oxidase(s) is connoted.

Amine Oxidase (Copper-Containing)↗
PubMed1975

Phenethylamine in normal urine: failure to verify high values.

The phenethylamine (PEA) level in daytime urine samples of 18 normal subjects was measured by an isotope dilution technique. Purification of PEA from other urinary substance, after the addition of 1-14C-PEA to urine samples, was achieved by the sequence: thin-layer chromatography (TLC), derivatization, TLC, and finally, gas chromatography (electron capture). The estimated mean daily output of PEA was 10.3 mug/day. A circadian rhythm was not evident on the basis of analyses of 24-hr urine collections from four normal subjects. Three acute schizophrenics had levels within the normal means.

Carbon Radioisotopes↗
PubMed1978

Concentrations of phenethylamine in dog following single doses and during intravenous self-administration.

A gas chromatographic procedure is described which was used to measure concentrations of beta-phenethylamine (PEA) in dog plasma following single or multiple infusions. Plasma levels were determined immediately following drug infusions during PEA self-administration sessions. At a unit dose of 3 mg/kg/infusion the concentration of PEA ranged from 1 to 3.95 microgram/ml of plasma, and from 2.5 to 4.75 microgram/ml at a unit dose of 6 mg/kg/infusion. At the time of responding for another infusion the plasma concentration varied between 0.16 and 0.52 microgram/ml and between 0.08 and 0.26 microgram/ml, for the two doses, respectively. Whole-body concentrations of PEA during self-administration were estimated according to a one compartment, open model using experimentally determined plasma half-lives obtained from single dose studies and inter-infusion intervals. Relatively little accumulation of PEA was predicted according to this model which correlated well with the experimental data. During the course of a self-administration session plasma levels rose initially following the infusion and declined to relatively constant levels ("response concentrations") when a subsequent drug-seeking response was made. Significant differences in "response concentrations" were observed between dogs and between doses. It is suggested that this response pattern is related to the distribution and clearance rate of the drug from plasma and well-perfused tissues.

Animals↗
PubMed1977

Cactus alkaloids XXXIII: beta-phenethylamines from the Guatemalan cactus Pilosocereus maxonii.

TLC analysis of extracts of Pilosocereus maxonii (Rose) Byles and Rowley detected six identifiable alkaloids. Preparative TLC aided in the crystallization of the hydrochlorides of N-methyl-3,4-dimethoxyphenethylamine, N-methyl-3-methoxytyramine, and N,N-dimethyl-3-methoxytyramine. Traces of 3,4-dimethoxyphenethylamine (TLC and mass spectrometry), tyramine (TLC), and N-methyltyramine (TLC) were identified. While all of these compounds were isolated and/or detected previously in other cactus species, this study is the first reported crystallization of N-methyl- and N,N-dimethyl-3-methoxytyramine from a natural source.

Alkaloids↗