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At least 487 records · Page 27Linked to original sources
PubMed1994

NE-100, a novel sigma receptor ligand: effect on phencyclidine-induced behaviors in rats, dogs and monkeys.

Phencyclidine (PCP)-induced psychosis is a useful animal model for studies on schizophrenia. N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)-phenyl]- ethylamine monohydrochloride (NE-100) had no effect on conditioned avoidance responses (CAR) in rats, whereas, the PCP-induced impairment of avoidance inhibition was attenuated by NE-100. The PCP-induced ataxia or decreased attention in rhesus monkeys was to some extent overcome by NE-100. In dogs, PCP-induced either head-weaving behavior or ataxia, effects which were blocked by NE-100. Administration of PCP led to an increase in beta-2 and a decrease in delta relative power (RP) activity in cortical background spectral electroencephalographics (ECoG) in dogs. While NE-100 in itself showed no significant change in beta-2 and delta RP, NE-100 did block the PCP-induced beta-2 increase and delta decrease. These findings indicate that NE-100 attenuates the effect of PCP in experimental animals. This drug is being considered as a therapeutic for the treatment of patients in the schizophrenia.

Animals↗
PubMed1995

Autoradiographic characterization of binding sites for [3H]NE-100 in guinea pig brain.

The receptor binding specificity and neuroanatomical distribution of [3H]NE-100 (N, N-dipropyl-2-[4-methoxy-3-(2- phenylethoxy) phenyl] ethylamine monohydrochloride)-labeled sigma receptor in guinea pig brain were examined using quantitative autoradiography. NE-100 potently inhibited [3H]NE-100 binding to slide-mounted sections of guinea pig brain with the IC50 value of 1.09 nM, therefore, NE-100 apparently has high affinity binding sites. Competition studies, under conditions similar to those used to visualize the receptor, yielded the following rank order of potency: NE-100 > haloperidol > DuP734 > (+)pentazocine >> (-)pentazocine. Non-sigma ligands such as phencyclidine (PCP), MK-801 and (-)sulpiride had negligible affinities for [3H]NE-100 binding sites. High densities of [3H]NE-100 binding sites displaceable by haloperidol were present in the granule layer of the cerebellum, the cingulate cortex, the CA3 region of the hippocampus, the hypothalamus and the pons. The distribution of [3H]NE-100 binding sites was consistent with that of [3H](+)pentazocine, a sigma 1 ligand. These sigma sites may possibly be related to various aspects of schizophrenia.

Animals↗
PubMed1993

Venlafaxine exhibits pre-clinical antidepressant activity in the resident-intruder social interaction paradigm.

Venlafaxine, a novel 2-phenyl-2-(1-hydroxycycloalkyl) ethylamine, is a potent inhibitor of 5-hydroxytryptamine and noradrenaline reuptake and exhibits a profile of activity in pre-clinical in vitro biochemical studies predictive of antidepressant activity. The studies described here examined the effects of acute and chronic treatment with venlafaxine on the behaviour of resident rats confronted with an unfamiliar, non-treated, intruder conspecific. Ethological analysis of the social encounters revealed that acute, subcutaneous, treatment with venlafaxine, 20-180 mumol kg-1, induced a selective, dose-related, reduction in aggressive behaviour (ID50 = 24.87 mumol kg-1) concomitant with increased flight behaviour. In contrast, chronic treatment with venlafaxine, 20 mumol kg-1 day-1, via subcutaneously-implanted osmotic mini-pumps, induced a marked elevation in aggressive behaviour concomitant with reduced flight behaviour. These diametrically opposite effects of acute and chronic venlafaxine treatment on the agonistic behaviour of resident rats are consistent with the behavioural effects of similar treatment regimes previously identified for a range of antidepressant drugs that differ widely in their acute pharmacology. These data strongly support the potential antidepressant activity of venlafaxine and are consistent with the results of recent clinical trials which demonstrate that venlafaxine exhibits significant antidepressant activity.

Aggression↗
PubMed1996

Behavioral evidence for modulation by sigma ligands of (+)MK-801-induced hyperlocomotion in monoamine-depleted mice.

The selective non-competitive N-methyl-D-aspartate (NMDA) antagonist (+)-5-methyl-10, 11-dihydro-5H-dibenzo(a, d)cyclohepten-5,10-imine maleate ((+)MK-801) led to a dose-dependent increase in locomotor activity in mice pretreated with a combination of reserpine and alpha-methyl-para-tyrosine (alpha-MT). A selective and potent sigma receptor "antagonist" NE-100 (N, N-dipropyl-2- [4-methoxy-3-(2-phenylethoxy)-phenyl]-ethylamine monohydrochloride), which did not per se affect spontaneous locomotor activity, did not prevent the locomotor stimulatory effects of (+)MK-801. Sulpiride, a dopamine D2 receptor antagonist, and clozapine, a dopamine D4 receptor antagonist, which decreased spontaneous locomotor activity, did not prevent the locomotor stimulatory effects of (+)MK-801. The sigma receptor "agonists" (+)N-allynormetazocine [(+)SKF10,047], (+)pentazocine and (+)-3-(3-hydroxyphenyl)-N-(1-propyl) piperidine [(+)3-PPP], which did not per se affect spontaneous locomotor activity, did dose-dependently enhance the hyperlocomotion induced by (+)MK-801. The enhancement of (+)MK-801-induced the hyperlocomotion by (+)SKF10,047, (+)pentazocine and (+)3-PPP was completely blocked by NE-100. The enhancement of (+)MK-801-induced hyperlocomotion by (+)pentazocine was not affected by treatment with sulpiride and clozapine. As sigma ligands can markedly attenuate NMDA antagonist-induced behavior, the major physiological role of sigma receptors in vivo might be to modulate functions of the NMDA receptor ion channel complex.

Animals↗
PubMed1991

Pharmacokinetic and pharmacodynamic properties of some phencyclidine analogs in rats.

The pharmacodynamics and pharmacokinetics of three phencyclidine analogs, differing from phencyclidine (PCP) only in the nature of the amine structure, were determined after intravenous doses of equimolar amounts to rats. The purpose of the study was to assess the role of pharmacokinetics in the in vivo potency of the compounds. The compounds examined were phenylcyclohexyl-pyrrolidine (PCPY), diethylamine (PCDE), ethylamine (PCE), and phencyclohexylamine (PCA). The behavior responses monitored included ataxia and others previously shown to be characteristic of PCP. In contrast to their relative affinities for the MK 801 binding site, the behavioral potencies of PCE, PCDE and PCPY were comparable to PCP. The major discrepancy occurred with PCDE, whose affinity for the NMDA receptor was 1/20th of PCP. The pharmacokinetic studies showed that the discrepancy between in vivo and in vitro activity of PCDE could be partially accounted for by its conversion to PCE, a relatively potent PCP-like agent.

Animals↗
PubMed1993

Behavioral sensitization and tolerance to the D2 agonist RU 24213: dissociation between several behavior patterns in mice.

Previous studies have shown that different components of behavioral effects of indirect agonists given chronically to laboratory rodents can follow different courses during treatment. Whether repeated injections of a D2 agonist can lead to the same phenomenon was investigated in mice using the D2 agonist N-n-propyl-N-phenylethyl-p-(3-hydroxy-phenyl)-ethylamine (RU 24213). Five mutually exclusive behaviors were examined over seven intermittent administrations (every other day over 13 daily injections) of RU 24213 (2.5 mg/kg SC) in mice. Rapid tolerance to the clearest initial effect of RU 24213, stillness, was found. Suppression of grooming also showed tolerance later in the treatment regimen (from the fourth test). From the third test, parallel time courses of sensitization were obtained for ambulation and rearing. Sleeping position was strongly depressed throughout the chronic treatment. These results show that the development in time of the behavioral effects of RU 24213 injected chronically strongly depend upon the behavioral measure. This supports the use of multiple measures in the same animal in the behavioral analysis of chronically injected dopaminergic drugs.

Animals↗
PubMed1983

Activation of 2-amino-3-methylimidazo[4,5-f]quinoline and 2-aminofluorene for bacterial mutagenesis by primary monolayer cultures of adult rat hepatocytes.

Primary monolayer cultures of adult rat hepatocytes readily activate 2-amino-3-methylimidazo[ 4,5-f ]quinoline (IQ), a potent bacterial mutagen (Ames test) present in some cooked foods. In a co-culture system consisting of intact hepatocytes, bacteria, and IQ, the number of revertant colonies produced increased proportionately with hepatocyte density to a maximum at about 6 X 10(5) hepatocytes. When the density exceeded 6 X 10(5) hepatocytes per dish, the number of revertant colonies markedly declined. The decline was not due to bacterial death. In standard Ames tests disrupted hepatocytes prepared from similarly handled monolayer cultures or from hepatocytes just after isolation (uncultured), or rat-liver S9, were only about 1/10th as efficient as the co-cultured intact hepatocytes (at optimum density) in activating IQ for bacterial mutagenesis. In contrast, 2-aminofluorene was poorly activated by intact hepatocytes. Disrupted hepatocytes and rat-liver S9 in standard Ames tests were much more effective than co-cultured intact hepatocytes in activating 2-aminofluorene for bacterial mutagenesis. For intact hepatocytes an inhibitor of cytochrome P-450, 2-[(2,4-dichloro-6-phenyl)-phenoxyl]ethylamine, inhibited IQ activation by 94-98%, and AF activation by 64-70%.

Animals↗
PubMed1983

A mutagenic metabolite synthesized by Salmonella typhimurium grown in the presence of azide is azidoalanine.

A mutagenic azide metabolite was purified from the medium in which Salmonella typhimurium cells were grown in the presence of azide. This metabolite was identified to be azidoalanine based on infrared and mass spectroscopy and elemental analysis. This compound appeared to be identical to the mutagenic compound synthesized in vitro from azide and O-acetylserine by partially purified O-acetylserine sulfhydrylase. The metabolite (azidoalanine) mutagenic efficiency and spectrum in S. typhimurium was similar to that of inorganic azide. The compounds 2-azidoethylamine, 2-bromoethylamine, 3-bromopropionic acid and N-(azidomethyl) phthalimide were also mutagenic with a similar spectrum to azide and azidoalanine, but with lower efficiency. The compounds 3-azidopropylamine, 4-azidobutylamine, 3-chloroalanine and ethylamine were only weakly or nonmutagenic. Numerous other chloro, bromo and azido phthalimide derivatives tested were nonmutagenic. It is suggested that the lack of azide mutagenicity (and perhaps carcinogenicity) in mammalian cells may be due to their inability to convert azide to azidoalanine.

Alanine↗
PubMed1981

Histamine actions on activity of cultured hypothalamic neurons: evidence for mediation by H1- and H2-histamine receptors.

Tuberal hypothalamic tissue cultures were used to investigate the actions of histaminergic agents on neuronal activity using extracellular glass micropipettes. Histamine and H1- and H2-agonists were applied locally onto single active neurons by iontophoresis, while histaminergic antagonists were perfused through the bathing medium. Peri-event histogram and ratemeter analysis showed histamine to both excite and depress unit activity. Excitations were only antagonized by putative H1- and not H2-histamine antagonists, whereas inhibitions were antagonized by H2- and H2-antagonists. Dimaprit, a specific H2-agonist, elicited inhibitions of activity, while 2-(2-pyridyl)ethylamine, a putative H1-agonist, elicited both excitations and inhibitions. Two pharmacologically distinct populations of histamine receptors may exit in the hypothalamus: excitatory H2-receptors and inhibitory H2-receptors.

Animals↗
PubMed1991

Functional assessment and partial characterization of [3H](+)-pentazocine binding sites on cells of the immune system.

The existence of sigma receptors on lymphocytes and thymocytes was characterized using [3H](+)-pentazocine. [3H](+)-Pentazocine specifically labels high affinity sigma-type binding sites on T- and B-enriched lymphocyte membranes. The binding is saturable with T lymphocyte sites having a KD value of 401 +/- 85 nM and B lymphocyte sites having a KD value of 302 +/- 46 nM. Likewise, saturable high (KD1 277 +/- 92 nM) and low (KD2 2.5 +/- 1.2 microM) affinity sites for [3H](+)-pentazocine are found on thymocytes as well. In competition studies with lymphocytes, the rank order of potency for competing ligands is (+)-pentazocine = N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2- (1-pyrrolidinyl)ethylamine (BD1008) greater than 1R,2S-(+)-cis-N-(2-(3,4-dichlorophenyl)ethyl]-2- (1-pyrrolidinyl)cyclohexylamine (LR132) greater than or equal to (-)-pentazocine greater than or equal to phenazocine greater than (+/-)-trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] benzeneacetamide methanesulphonate (U-50,488H) = phencyclidine greater than haloperidol = 1,3-di- (o)-tolylguanidine. In competition studies with thymocytes, the rank order of potency for competing ligands is (+)-pentazocine = BD1008 greater than or equal to phenazocine greater than haloperidol greater than 1,3-di-(o)-tolylguanidine greater than phencyclidine greater than (-)-pentazocine. These compounds were also investigated as potential regulatory molecules in mitogen-stimulated lymphocyte proliferation assays. Of the compounds tested, phencyclidine, 1,3-di-(o)-tolylguanidine, haloperidol, and (+)-pentazocine suppress concanavalin A-induced proliferation at high (10(-5) M) concentrations while (-)-pentazocine is inactive. When pokeweed mitogen or lipopolysaccharide are used, these compounds enhance or suppress lymphocyte proliferation depending on the mitogen and concentration of ligand. These results indicate a stereoselective receptor for (+)-pentazocine which is coupled to biological processes of lymphocytes.

Animals↗
PubMed1983

High concentrations of dimethylamine and methylamine in squid and octopus and their implications in tumour aetiology.

The levels of the common secondary amines in various squid, in octopus and in 17 other seafoods were determined by HPLC. Ammonia and dimethylamine were found in all of the seafoods tested and some of them also contained methylamine and/or ethylamine. Particularly high levels of dimethylamine (946-2043 ppm) and methylamine (38-255 ppm) were detected in various species of squid and in the octopus. Reaction of nitrite in acidic medium with aqueous extract of squid yielded appreciable amounts of N-nitrosodimethylamine. The optimum pH for this reaction was around 2.4. Dimethylamine in dried squid tissues was readily extracted with water or 1% sodium carbonate solution. Heat treatment of dried squid at 200 degrees C was found to increase its amine content dramatically. It appeared that pyrolytic decarboxylation of some amino acids might cause this increase. Squid is a popular seafood in Japan and other oriental countries. The high incidence of stomach cancer in Japan and China is thought by epidemiologists to be associated with traditional Japanese and Chinese diets. Our present finding that squid and other seafoods contain unusually high levels of dimethylamine and other amines adds to the evidence that dietary factors may have an important role in the aetiology of stomach cancer and other gastro-intestinal tumours.

Animals↗
PubMed1995

Nitrosatable amines and nitrosamide formation in natural stimulants: Cola acuminata, C. nitida and Garcinia cola.

Three varieties of kola nut, Cola acuminata, C. nitida and Garcinia cola, of Nigerian origin, were analysed for their content of primary and secondary amines, and assessed for their relative methylating potential due to nitrosamide formation. Primary and secondary amines were determined as benzene sulfonamides by gas chromatography/thermal energy analysis (GC/TEA). Dimethylamine, methylamine, ethylamine and isopentylamine were detected in all kola nut varieties, while pyrrolidine, piperidine and isobutylamine were detected in one or more varieties. Estimated average total daily intake of aliphatic amines by a typical kola nut chewer varied from 260 to 1040 micrograms/day for secondary amines and from 2430 to 9710 micrograms/day for primary amines. Methylating activity of the nitrosated kola nuts, expressed as N-nitroso-N-methylurea equivalents, was also determined by GC/TEA. Methylating activity was significantly higher in kola nuts (170-490 micrograms/kg) than has ever been reported for a fresh plant product. These data suggest that the possible role of kola nut chewing in human cancer aetiology should be explored in countries where kola nuts are widely consumed as stimulants.

Amines↗
PubMed1978

Formation of amino acids from aliphatic nitriles and aliphatic amines by contact glow discharge electrolysis.

Contact glow discharge electrolyses (CGDE) were carried out relative to the prebiotic formation of amino acids by amination of aliphatic nitrile in aqueous ammoniacal solution, and by cyanization of aliphatic amine by sodium cyanide. The CGDE of propionitrile by amination followed by hydrolysis resulted in the formation of glycine, alanine and beta-alanine. The reaction of ethylamine by cyanization, gave glycine, alanine, beta-alanine, aspartic acid, and serine. In these reactions, a relatively high ratio of glycine was observed. This could be explained by the cleavage of the alpha,beta-carbon bond, which was broken easily, due to the strong electron-attracting property of the nitrile group of propionitrile and the resulting alpha-aminopropionitrile.

Amines↗
PubMed1979

Effects of estrogens on the characteristics of [3H]spiroperidol and [3H]RU24213 binding in rat anterior pituitary gland and brain.

Since estrogens have been found to exert a marked inhibitory effect on dopaminergic action at the anterior pituitary and striatal levels in the rat, the effect of estrogen treatment has been studied on the binding characteristics of the dopamine (DA) antagonist [3H]spiroperidol and of the new DA agonist [3H]N-n-propyl-N-phenylethyl-beta-(3-hydroxyphenyl)ethylamine hydrochloride ([3H]RU24213) in rat striatum, nucleus accumbens + olfactory tubercle, frontal cortex and anterior pituitary gland. Specificity of binding was carefully examined in order to investigate possible changes of the agonist and antagonist states of the DA receptor. Estrogen treatment led to a small increase (approx. 20%) of [3H]spiroperidol and [3H]RU24213 binding in rat striatum, nucleus accumbens + olfactory tubercle and frontal cortex while no significant effect was found in the anterior pituitary gland. That the increased binding is due to a corresponding increased number of binding sites and not to higher affinity is indicated by the absence of effect of estrogen treatment on the IC50 values for displacement of the two labeled ligands by a variety of unlabeled compounds. Specificity of binding of DA agonists and antagonists remained unchanged after estrogen treatment. The present data suggest that the potent desensitizing effect of estrogen on DA action at the striatal and pituitary levels is exerted at a step subsequent to binding of DA to its receptor.

Animals↗
PubMed1994

Precursors of N-nitroso compounds in some Nigerian medicinal plants.

Twenty-seven tropical plants of medicinal importance were analysed for primary and secondary amines by chemiluminescence detection on a Thermal Energy Analyzer (TEA) modified for use on 'nitrogen mode' following derivatization with benzene sulphonyl chloride (BSC) and gas chromatographic (GC) separation of their sulphonamides. Nitrite was determined by colorimetry at 540 nm after diazotization with sulphanilamide and coupling with N-(1-naphthyl)ethylenediamine to form an azo dye. Nitrate was determined as nitrite following on-line reduction by granulated cadmium. Dimethylamine in the range of 0.5 ppm to 18.2 ppm was detected in 96% of samples, while pyrrolidine ranged between 0.7 ppm and 12.78 ppm in 14 samples. Isobutylamine, methylamine and ethylamine were the most ubiquitous primary amines. Largest number of secondary amines (four) was found in Azadirachta indica (Neem) while largest number of primary amines (six) was detected in Azadirachta indica and Tamarindus indica (Tsamiya) which also contained the highest amount of total primary amines (148.8 ppm). Nitrate and nitrite were seldom found in plant extracts whose pH were generally below 7.0. These findings suggests that early exposures to precursors of N-nitroso compounds via medicinal plants might contribute to total risk posed by environmental carcinogens in Nigeria.

Amines↗
PubMed1980

Specific activation of cyclic AMP-dependent protein kinase(s) by H2-histamine agonists in isolated gastric mucosal cells from guinea-pig.

Histamine stimulated cyclic AMP-dependent protein kinase activity in dispersed mucosal cells from guinea-pig gastric fundus (Ka = 5 microM). The H2-agonists dimaprit and impromidine produced similar effects, while the H1-agonist 2-(2-pyridyl) ethylamine had only a weak one. The H2-antagonist cimetidine competitively inhibited 0.1 mM histamine stimulation (Ki = 2 microM). In contrast, the H1-antagonist diphenhydramine had no effect up to 1 mM.

Animals↗
PubMed1992

The action of the psychoactive drug 2C-B on isolated rat thoracic aorta.

1. 2C-B [2-(4-bromo-2,5-dimethoxyphenyl)ethylamine] elicits concentration-dependent contraction of the rat thoracic aorta (apparent pD2 = 4.55). The maximal contraction (Emax) attained with 2C-B is less than that produced by either norepinephrine (NE) or serotonin (5-HT). 2. Pretreatment with either prazosin (5 x 10(-9) - 10(-8) M) or ketanserin (5 x 10(-9) - 10(-8) M) leads to decreased slopes and Emax in the 2C-B dose-response curves. 3. 2.82 x 10(-5) M 2C-B potentiates the response to low concentrations of NE; 5 x 10(-5) M 2C-B shows similar behaviour, but with reduced Emax. At 10(-6) M 2C-B acts as a competitive 5-HT antagonist; at 2.8 x 10(-5) M, however, it behaves like a non-competitive 5-HT antagonist. 4. Removal of the endothelial lining from the aortal rings only shifts the 2C-B dose-response curve to the left. 5. These results suggest that 2C-B behaves as a partial agonist toward both alpha 1-adrenergic and 5-HT2 serotonergic receptors. The endothelium only seems to act as a diffusional barrier to the drug.

Adrenergic alpha-Agonists↗