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Biomedical subjects

M Hirobe

Publications and source records attributed to M Hirobe.

At least 109 records · Page 6Linked to original sources
PubMed1985

Preparation of 13N-beta-phenethylamine.

Nitrogen-13-labelled beta-phenethylamine[( 13N]PEA) was synthesized by Hofmann rearrangement of [13N]phenylpropionamide prepared from phenylpropionyl chloride and aqueous [13N]ammonia solution. The reaction proceeded rapidly with a fairly good yield. [13N]PEA was isolated using preparative thin-layer chromatography, and organ distribution in mice was studied preliminarily. After i.v. administration of [13N]PEA, high accumulation and long-term retention of the radioactivity were observed in the brain and the heart.

Animals↗
PubMed1985

Intrinsic activity and effects of guanyl-5'-yl imidodiphosphate, Gpp(NH)p and sodium ion on the affinity of dynorphin 1-13, nalorphine and nalorphine-7,8-oxide to kappa-opioid receptor.

Nalorphine and nalorphine-7,8-oxide (nalorphine epoxide) behaved as partial agonists on the kappa-receptor in the electrically stimulated mouse vas deferens. The effects of a GTP-analogue, GppNHp and Na+ on the inhibition of [3H]ethylketocyclazocine binding by dynorphin 1-13, nalorphine, its epoxide and naloxone (antagonist) were studied with a synaptosomal fraction of guinea pig brain (except a cerebellum) and compared with the intrinsic activity of the test drugs, which was estimated in the electrically stimulated mouse vas deferens. The effects of GppNHp and Na+ on the affinity of the drugs to the kappa-receptor correlated with their intrinsic activities.

Animals↗
PubMed1985

Interactions of codeine-7,8-oxide (codeine-epoxide), as a new metabolite of codeine, with multiple opiate receptors.

Interactions of codeine-epoxide, a new metabolite of codeine, with multiple opiate receptors were studied using radioligand binding assay. The ability of codeine-epoxide to displace [3H]dihydromorphine binding was the most effective among three labeled ligands, that is, [3H]dihydromorphine, [3H]-D-Ala2-D-Leu5-enkephalin and [3H]ethylketocyclazocine, suggesting that codeine-epoxide had a selectively high affinity to mu-receptors, despite the fact the affinities of codeine-epoxide to opiate receptors were slightly less potent than its parent compound, codeine. Since "sodium ratio" and "GTP ratio" on codeine-epoxide binding lay between those of codeine and naloxone, the interaction of codeine-epoxide with opiate receptors may be slightly different from that of codeine.

Animals↗
PubMed1984

Interaction of morphine-epoxide with multiple opiate receptors.

We examined the interaction of morphine-epoxide, which was assumed to be a new metabolite of morphine, with opiate receptor subtypes using pharmacological and biochemical techniques. Morphine-epoxide was about 3 to 4 times less potent than morphine to the interactions of opiate receptors. However, the ratio of IC50 values for the guinea pig ileum and mouse vas deferens to electrical field stimulation and the ratio of IC50 values for the [3H]-dihydromorphine and [3H]-D-ala2-D-leu5 enkephalin binding to rat brain membrane preparations of morphine-epoxide was similar to those of morphine. Morphine-epoxide had virtually no effect on the twitch responses of rabbit and rat vas deferens. Furthermore, "sodium ratio" and "GTP ratio" of morphine-epoxide were similar to those of morphine and differed from naloxone. These results suggest that morphine-epoxide as well as morphine behaves as the agonist on the mu type opiate receptor notwithstanding that the affinity of morphine-epoxide is slightly less than that of morphine.

Analgesics↗
PubMed1983

Determination of serum tulobuterol concentrations by mass fragmentography: comparison with an electron-capture gas chromatographic method.

A simple and sensitive method is reported for the quantitative determination of the bronchodilator tulobuterol in human serum. Tulobuterol and an internal standard were extracted from alkalinized serum with ether and then back-extracted into dilute hydrochloric acid. After alkalinization and extraction of the aqueous solution, the extract was evaporated to dryness. The residue was silylated and subjected to mass fragmentography.

Chromatography, Gas↗
PubMed1982

Photoaffinity labeling of opioid receptor with morphine-7,8-oxide (morphine epoxide).

The opioid receptor mediating inhibitory action of morphine in the electrically stimulated guinea pig ileum was irreversibly photoinactivated by morphine epoxide (3 X 10(-6) M). Morphine epoxide (up to 3 X 10(-5) M) did not influence the responses of rat vas deferens (epsilon-receptor) or rabbit vas deferens (kappa-receptor) to electrical stimulation. Effective concentrations of morphine epoxide were much lower in the guinea pig ileum (mu-receptor) than in the mouse vas deference (delta-receptor). The inhibitory action of [Met]-enkephalin on the twitch responses of the rat vas deferens and mouse vas deferens to electrical stimulation were not influenced after irradiation in the presence of morphine epoxide (3 X 10(-6) M). Therefore, morphine epoxide is probably a useful probe for photoaffinity labeling of the mu-receptor in vitro.

Affinity Labels↗
PubMed1982

Some pharmacological properties of morphine-7,8-oxide (morphine epoxide).

Morphine-7,8-oxide (morphine epoxide) is assumed to be a metabolite of morphine. Morphine epoxide in antinociceptive action was practically as potent as morphine. The development of tolerance in antinociceptive action was slower in the rats treated with morphine epoxide than in the rats with morphine. Furthermore, morphine epoxide was less potent than morphine in the inhibition of abstinence syndrome.

Analgesics↗
PubMed1981

Quantitative determination of tulobuterol and its metabolites in human urine by mass fragmentography.

A method is described for the simple and simultaneous determination of tulobuterol and its metabolites in human urine by gas chromatography--mass spectrometry. Quantification was achieved by single-ion monitoring at m/e 86 derived from trimethylsilyl-tulobuterol and its metabolites using a column packed with a mixed phase, 2% OV-1--2% QF-1 (1 : 1, w/w). The detection limits were estimated to be 2 ng/ml in urine for tulobuterol and 5 ng/ml for metabolites, respectively.

Bronchodilator Agents↗