∆-Tetrahydrocannabinol, a major marijuana component, enhances the anesthetic effect of pentobarbital through the CB receptor.

Purpose: ∆ Tetrahydrocannabinol (∆-THC) and cannabidiol (CBD), major psychoactive constituents of marijuana, induce potentiation of pentobarbital-induced sleep in mice. We have elucidated the mechanism of enhancement of the anesthetic effect of pentobarbital by cannabinoids.

Methods: We carried out pharmacological experiment and cannabinoid (CB) receptor binding assay using CB antagonists to clarify whether the CB receptor is involved in the synergism or not.

[Historical studies on the origins of pharmaceutical sciences in Hyuga (Miyazaki). (Part 10)--students from Hyuga (Miyazaki) who studied under Sanyou Rai in Osaka and Toyou Yamawaki in Kyoto during the late Edo period].

This paper is part 10 of a historical article on young students from Hyuga who went to Osaka or Kyoto to study in the Edo period. The article investigates the influence of these students on medical and pharmaceutical sciences in the Hyuga, which is now Miyazaki-Prefecture. The knowledge in this area is limited, thus, we aimed to examine and summarize the historical events.

Cannabidiol-2',6'-dimethyl ether, a cannabidiol derivative, is a highly potent and selective 15-lipoxygenase inhibitor.

The inhibitory effect of nordihydroguaiaretic acid (NDGA) (a nonselective lipoxygenase (LOX) inhibitor)-mediated 15-LOX inhibition has been reported to be affected by modification of its catechol ring, such as methylation of the hydroxyl group. Cannabidiol (CBD), one of the major components of marijuana, is known to inhibit LOX activity. Based on the phenomenon observed in NDGA, we investigated whether or not methylation of CBD affects its inhibitory potential against 15-LOX, because CBD contains a resorcinol ring, which is an isomer of catechol.

Generation of reactive oxygen species during mouse hepatic microsomal metabolism of cannabidiol and cannabidiol hydroxy-quinone.

We investigated whether cannabidiol (CBD) and cannabidiol hydroxy-quinone (CBDHQ) generate reactive oxygen species (ROS) during metabolism with mouse hepatic microsomes. CBD and CBDHQ (91.5 microM) significantly suppressed lipid peroxidation in the mouse hepatic microsomes.

Isolation of cytochrome P450 3A (CYP3A) inhibitors from Hyuganatsu, Citrus tamurana Hort.

The present study was conducted to identify cytochrome P450 3A (CYP3A) inhibitory components of Hyuganatsu, Citrus tamurana Hort., by investigating the effects on midazolam 1'-hydroxylase activity of human liver microsomes. As a consequence, limonin and nomilin were identified as CYP3A inhibitors from the endocarp of Hyuganatsu.

Structural and functional characterization of rabbit and human L-gulonate 3-dehydrogenase.

L-Gulonate 3-dehydrogenase (GDH) catalyzes the NAD(+)-linked dehydrogenation of L-gulonate into dehydro-L-gulonate in the uronate cycle. In this study, we isolated the enzyme and its cDNA from rabbit liver, and found that the cDNA is identical to that for rabbit lens lambda-crystallin except for lacking a codon for Glu(309). The same cDNA species, but not the lambda-crystallin cDNA with the codon for Glu(309), was detected in the lens, which showed the highest GDH activity among rabbit tissues.

Molecular characterization of two monkey dihydrodiol dehydrogenases.

Japanese monkey liver contains multiple forms of dihydrodiol dehydrogenase with 3(20)alpha-hydroxysteroid dehydrogenase activity. Here we have purified the major and minor forms (DD1 and DD4) of the enzyme from Cynomolgus monkey liver, and isolated cDNA species for the two enzyme forms by reverse transcription-PCR. The cDNAs encoded proteins comprising of 323 amino acids, in which the sequence identity between DD1 and DD4 was 83%.

Characterization of two isoforms of mouse 3(17)alpha-hydroxysteroid dehydrogenases of the aldo-keto reductase family.

Mouse kidney contains two 3(17)alpha-hydroxysteroid dehydrogenases (HSDs) that show essentially the same properties except for their isoelectric points. However, the structural differences and physiological roles of the two enzymes remain unknown. In this study, we have isolated cDNAs for the two 3(17)alpha-HSDs from a total RNA sample of mouse kidney by reverse transcription-PCR.

Crystal structure of human L-xylulose reductase holoenzyme: probing the role of Asn107 with site-directed mutagenesis.

L-Xylulose reductase (XR), an enzyme in the uronate cycle of glucose metabolism, belongs to the short-chain dehydrogenase/reductase (SDR) superfamily. Among the SDR enzymes, XR shows the highest sequence identity (67%) with mouse lung carbonyl reductase (MLCR), but the two enzymes show different substrate specificities. The crystal structure of human XR in complex with reduced nicotinamide adenine dinucleotide phosphate (NADPH) was determined at 1.

Structural determinant for cold inactivation of rodent L-xylulose reductase.

L-Xylulose reductase (XR) is a homotetramer belonging to the short-chain dehydrogenase/reductase family. Human XR is stable at low temperature, whereas the enzymes of mouse, rat, guinea pig, and hamster are rapidly dissociated into their inactive dimeric forms. In order to identify amino acid residues that cause cold inactivation of the rodent XRs, we have here selected Asp238, Leu242, and Thr244 in the C-terminal regions of rodent XRs and performed site-directed mutagenesis of the residues of mouse XR to the corresponding residues (Glu, Trp, and Cys) of the human enzyme.

Identification of amino acid residues involved in substrate recognition of L-xylulose reductase by site-directed mutagenesis.

L-Xylulose reductase (XR) catalyzes the oxidoreduction between xylitol and L-xylulose in the uronate cycle. The enzyme has been shown to be identical to diacetyl reductase, an enzyme that reduces alpha-dicarbonyl compounds. XR belongs to the short-chain dehydrogenase/reductase family, and shows high sequence identity with mouse lung carbonyl reductase (MLCR), an enzyme that reduces 3-ketosteroids but not sugars.

Selective and potent inhibitors of human 20alpha-hydroxysteroid dehydrogenase (AKR1C1) that metabolizes neurosteroids derived from progesterone.

Neuroactive steroids, such as 3alpha,5alpha-tetrahydroprogesterone (3alpha,5alpha-THP) and 3alpha,5alpha-tetrahydrodeoxycorticosterone have been shown to be synthesized from progesterone in animal brains. Comparison of kinetic constants for the neuroactive steroids and their precursors among four human 3(20)alpha-hydroxysteroid dehydrogenases (AKR1C1-AKR1C4) suggests that AKR1C1 and AKR1C2 are involved in the catabolism and synthesis, respectively, of the neuroactive steroids in the human brain. In our efforts to identify agents that would specifically inhibit the two enzymes, benzbromarone and 3',3",5',5"-tetrabromophenolphthalein were found to be relatively selective and potent inhibitors of AKR1C1.

Cloning, expression and tissue distribution of a tetrameric form of pig carbonyl reductase.

In this study, we isolated a cDNA for tetrameric carbonyl reductase (CR) from pig heart. The pig CR showed high amino acid sequence identity (81%) with rabbit NADP(+)-dependent retinol dehydrogenase (NDRD). The purified recombinant pig CR and NDRD were about 100-kDa homotetramers and exhibited high reductase activity towards alkyl phenyl ketones, alpha-dicarbonyl compounds and all-trans-retinal.

Crystallization and preliminary crystallographic analysis of human L-xylulose reductase.

Human L-xylulose reductase was crystallized from buffered polyethylene glycol solutions using the hanging-drop vapour-diffusion method. The crystals diffract to 2.1 A resolution and belong to the orthorhombic P222 space group, with unit-cell parameters a = 72.

Substrate specificity of human 3(20)alpha-hydroxysteroid dehydrogenase for neurosteroids and its inhibition by benzodiazepines.

In this report, we compared kinetic constants and products in the reduction of the neurosteroids, 3alpha,5alpha-tetrahydroprogesterone (3alpha,5alpha THP) and 3alpha,5alpha-tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC), and their precursors, 5alpha-dihydroprogesterone (5alpha-DHP), 5alpha-dihydrodeoxycorticosterone (5alpha-DHDOC) and progesterone, by three isoenzymes (AKR1C1, AKR1C2 and AKR1C3) of human 3alpha-hydroxysteroid dehydrogenase. AKR1C1 efficiently reduced 3alpha,5alpha-THP, 5alpha-DHP and progesterone to their 20alpha-hydroxy metabolites, and slowly converted 5alpha-DHDOC to 3alpha,5alpha-THDOC. AKR1C2 exhibited low 20-ketoreductase activity for 3alpha,5alpha-THP and moderate 3-ketoreductase activity for 5alpha-DHP and 5alpha-DHDOC.

Molecular characterization of mammalian dicarbonyl/L-xylulose reductase and its localization in kidney.

In this report, we first cloned a cDNA for a protein that is highly expressed in mouse kidney and then isolated its counterparts in human, rat hamster, and guinea pig by polymerase chain reaction-based cloning. The cDNAs of the five species encoded polypeptides of 244 amino acids, which shared more than 85% identity with each other and showed high identity with a human sperm 34-kDa protein, P34H, as well as a murine lung-specific carbonyl reductase of the short-chain dehydrogenase/reductase superfamily. In particular, the human protein is identical to P34H, except for one amino acid substitution.

Crystallization and preliminary X-ray diffraction analysis of monkey dimeric dihydrodiol dehydrogenase.

Dihydrodiol dehydrogenase catalyzes the NADP(+)-linked oxidation of trans-dihydrodiols of aromatic hydrocarbons to corresponding catechols and exists in multiple forms in mammalian tissues. The dimeric form of mammalian dihydrodiol dehydrogenase has a primary structure distinct from the previously known mammalian enzymes and may constitute a novel protein family with the prokaryotic proteins. Monkey kidney dimeric dihydrodiol dehydrogenase was crystallized from buffered ammonium phosphate solution using the hanging-drop vapour-diffusion method.