Inhibition of transformation of mammary preneoplastic nodules to tumor in C3H mice fed a phenylalanine-deficient diet.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Y H Hui
Publications and source records attributed to Y H Hui.
Ethanol with small doses of morphine establishes a conditioned place preference.
Conditioned place preference (CPP) testing is a way of indexing the reinforcing efficacy of drugs among rats. CPP testing involves using an alley with two distinctive sides. Typically, rats have drug experiences on one side and placebo experiences on the other. At testing, without drugs, their preference for side is tabulated. Rats' (6 groups of 12 each) place preferences were assessed before and after they were placed, once a day for 9 days, in the putative side of conditioning, and on 3 interspersed days, in the other side. During putative conditioning, one group received saline prior to being placed in both sides (a control group). Two groups had either morphine (2.0 mg/kg) or ethanol (0.5 g/kg) with the putative side of conditioning and saline with the other side. Three groups received morphine plus ethanol before being placed in the putative side of conditioning and either saline, morphine, or ethanol in the other side. At testing, rats that received morphine plus ethanol on side of putative conditioning showed a strong CPP whereas others did not. Results are compatible with the idea that ethanol's reinforcing effect is enhanced when there is a surfeit of opioidergic activity.
Animals↗
Functional characterization of the novel neuronal nicotinic acetylcholine receptor ligand GTS-21 in vitro and in vivo.
(2.4)-Dimethoxybenzylidene anabaseine dihydrochloride (GTS-21), a compound that interacts with rat neuronal nicotinic acetylcholine receptors (nAChRs), was evaluated using human recombinant nAChRs in vitro and various pharmacokinetic and behavioral models in rodents, dogs and monkeys. GTS-21 bound to human alpha 4 beta 2 nAChR (K1-20 nM) 100-fold more potently than to human alpha 7 nAChR, and was 18- and 2-fold less potent than (-)-nicotine at human alpha 4 beta 2 and alpha 7 nAChR, respectively. Functionally. GTS-21 stimulated [5H]dopamine release from rat striatal slices with an EC50 of 10 +/- 2 microM (250-fold less potent and 70% as efficacious as (-)-nicotine), an effect blocked by the nAChR antagonist dihydro-beta-erythroidine. However, GTS-21 did not stimulate human alpha 4 beta 2 nor human ganglionic nAChRs significantly. In vivo, GTS-21 had no adverse effect on dog blood pressure (< or = 2.5 micromol/kg i.v. bolus infusion), in marked contrast with (-)-nicotine, GTS-21 (-62 micromol/kg.s.e.) also did not cross-discriminate significantly with (-)-nicotine in rats and did not reduce temperature or locomotion in mice. Neither was it active in the elevated plus maze anxiety model (0.19-6.2 micromol/kg.IP) in normal mice. However, GTS-21 did improve learning performance of monkeys in the delayed matching-to-sample task (32-130 nmol/kg.i.m.).
Animals↗
Justicidin B, a bioactive trace lignan from the seeds of Sesbania drummondii.
Explore the source record for details and available documents.
Animals↗
Bullatacin and bullatacinone: two highly potent bioactive acetogenins from Annona bullata.
Screening of crude extracts of the bark of Annona bullata showed cytotoxic and pesticidal activities. By monitoring with brine-shrimp lethality, two novel, extremely potent acetogenins, bullatacin [1] and bullatacinone [2], were isolated. Spectral and chemical methods identified bullatacin as a diastereomer of asimicin. Bullatacinone represents bullatacin with the lactone cleaved and reformed at the 4-OH. Compounds 1 and 2 show selective cytotoxicities in human tumor cell lines, and certain susceptible cells give ED50 values as low as 10(-12)-10(-15) micrograms/ml. Bullatacin was pesticidal at concentrations as low as 1 ppm, but bullatacinone lacked pesticidal activities. The known compounds liriodenine and (-)-kaur-16-en-19-oic acid were also isolated and were lethal to brine shrimp but were not significantly cytotoxic.
Antineoplastic Agents, Phytogenic↗
Bullatacin, bullatacinone, and squamone, a new bioactive acetogenin, from the bark of Annona squamosa.
Activity-directed fractionation of the stem bark of Annona squamosa, monitoring with brine shrimp lethality, led to the isolation of the highly bioactive acetogenins bullatacin [1] and bullatacinone [2], thus demonstrating a new abundant plant source for these potent compounds. A new keto-monotetrahydrofuran acetogenin with a ketolactone terminus, as first seen in bullatacinone [2], was also isolated, characterized by spectral analyses, and named squamone [3]. The cytotoxicities of 3 were increased significantly by reduction of the two keto groups to hydroxyls, and the tetrahydrosquamone [7] and bullatacinone [2] both showed selective cytotoxicities to MCF-7 human breast carcinoma. Liriodenine and (-)-kaur-16-en-19-oic acid were also isolated.
Antineoplastic Agents, Phytogenic↗
Annonaceous acetogenins: a review.
The Annonaceous acetogenins are a series of apparently polyketide-derived fatty acid derivatives that possess tetrahydrofuran rings and a methylated gamma-lactone (sometimes rearranged to a methyl ketolactone) with various hydroxyl, acetoxyl, and/or ketoxyl groups along the hydrocarbon chain. They exhibit a broad range of potent biological activities (cytotoxicity, antitumor, antimalarial, antimicrobial, immunosuppressant, antifeedant, and pesticidal). The sources, isolation, chemistry, biogenesis, and biological actions of these compounds, published to date, are tabulated and discussed. Strategies for structural elucidation are reviewed, and structural revisions and refinements are suggested for some of the previously published compounds.
Antineoplastic Agents, Phytogenic↗