Simultaneous determination of cysteine sulfinic acid and cysteic acid in rat brain by high-performance liquid chromatography

A sensitive and specific assay method for cysteine sulfinic acid (CSA) and cysteic acid (CA) using high-performance liquid chromatography has been developed. The method includes post-column derivatization of various amino acids with o-phthalaldehyde in the presence of 2-mercaptoethanol. The column packed with cation-exchange resin ($\text{ISC-07}\text{S1504}$, Shimadzu Sci entific instruments, Inc., Kyoto, Japan) was used for obtaining general separation of amino acids except CSA and CA, while the separation of CSA and CA was achieved using a strong-base anion exchange ($\text{ISA-07}\text{S2504}$, Shimadzu Scientific Instruments) column. The fluorescence peak area for CSA was linear between 20 pmol and 5 nmol, whereas that for CA was 10 pmol to 5 nmol. The regional distribution of CSA, CA, and other amino acids in the rat brain was studied using this new assay method.     

Effects of haloperidol and sulpiride on dopamine-induced inhibition of nucleus accumbens neurons

Microiontophoretic study was performed to elucidate dopaminergic mechanism in the nucleus accumbens (Acc) of rats anesthetized with chloral hydrate. Iontophoretically applied dopamine produced an inhibition of glutamate-induced firing in 28 (62%) out of 45 Acc neurons tested. The dopamine-induced inhibition of 14 Acc neurons was clearly antagonized by simultaneous application of haloperidol, and a partial antagonism by sulpiride was observed in 3 out of 10 Acc neurons. These results indicate that dopamine produces an inhibition of the Acc neuron and that, compared to haloperidol, sulpiride is a less potent blocker of the postsynaptic dopamine receptor involved in the dopamine-induced inhibition.     

Stress-Induced Alterations in Metabolism of Γ-Aminobutyric Acid in Rat Brain

The effect of a stressful manipulation on the metabolism of gamma-aminobutyric acid (GABA) in the rat brain was studied. Application of an immobilized stress to animals induced a significant increase in the striatal and hypothalamic GABA contents without affecting those in other central structures examined. It was also found that the increase in striatal GABA level preceded that in the hypothalamus. This increase in steady-state levels of GABA in the striatum and hypothalamus disappeared at 12 h after the termination of the application of stress for 3 h, which exhibited a maximal stimulatory action on the GABA contents in both central areas. The activity of L-glutamic acid decarboxylase was found to be significantly elevated in the striatum and hypothalamus following the stress application with a concomitant decrease in the content of L-glutamic acid, which is converted to GABA by the catalytic action of the latter enzyme. The in vivo turnover of GABA in the brain was estimated by taking advantages of the postmortem accumulation of GABA following decapitation and of the selective inhibitory action of a low dose of aminooxyacetic acid on the GABA degrading system, respectively. Analysis using these two different methods revealed that the cerebral turnover of GABA in vivo was not significantly altered under stressful situations despite of the increase in its steady-state level. These results suggest that central GABA system may respond to the input of painful stimuli resulting from the application of a severe physical and psychological stressor, in addition to the well-known functional alterations in catecholamine neurons. The functional significance of these alterations in the central GABA neurons is also discussed.     

Fine structure of the dorsal lingual epithelium of the Japanese monkey Macaca fuscata fuscata.

Filiform papillae, which were densely distributed all over the dorsal surface of the lingual body, were crown-shaped, with a central, circular area that sloped in the anterior direction and several branches that surrounded it in a semicircle from the back of the central area. Dome-shaped, fungiform papillae were scattered among these filiform papillae. At the posterior end of the lingual body, there were four circumvallate papillae. Prominent microridges and elevated intercellular borders were widely distributed in the central area of the filiform papillae and the interpapillar region. On the surface of the branches of the filiform papillae, microridges were rarely seen. On the surface of the fungiform papillae, indistinct microridges were observed. Histologically, the dorsal lingual epithelium revealed three different regions: the epithelium on the anterior side of the filiform papillae, the epithelium on the posterior side of the filiform papillae and the interpapillar epithelium. Whereas the basal and suprabasal cells are similar throughout, differences characterize the intermediate and surface layers. Keratohyalin granules appear predominantly in the intermediate layer in the epithelium on the anterior side of filiform papillae. In the epithelium on the posterior side of the filiform papillae, no keratohyalin granules occur and, instead, tonofibrils are prominent. The cells become significantly flattened. In the interpapillar epithelium, no keratohyalin granules are visible, and the tonofilaments occupy almost the entire cytoplasm of most cells in the intermediate and surface layers. The cells are larger in volume in these layers.     

Identification of Mutations in the Pigment Cell-Specific Gene Located at the Brown Locus in Mouse

The pigment cell-specific gene, located at the brown (b)-locus in mouse, encodes the protein that determines the type of melanin synthesized. This protein is known as tyrosinase-related protein, but here we tentatively term it b-locus protein to avoid confusions with the related sequence cross-hybridizing to the tyrosinase gene. In order to identify the mutation at the b-locus, we have cloned and characterized the b-locus protein gene of BALB/c mouse (b/b, c/c). The gene is about 18 kb long and organized into 8 exons and 7 introns. Sequence analysis of the b-locus protein gene reveals four base changes within the protein-coding regions: two missense mutations and two silent mutations. Two missense mutations result in the Cys to Tyr substitution at position 86 (codon 110) and the Arg to His substitution at position 302 (codon 326) of a b-locus protein molecule. Using allele-specific amplification, we confirmed that these missense mutations are actually present in the genomic DNA of two b-mutant strains examined, BALB/c and DBA/2 (b/b, C/C) mice, suggesting that these mutations are specific for the mutant mice at the b-locus. Moreover, we are able to show that the b-locus protein containing Tyr 86 is not reactive with the anti-b-locus protein monoclonal antibody, TMH-1, in transient expression assays.     

Production of (R)-1-phenylethanol through enantioselective oxidation of (S)-isomer from their racemic mixture by Pachysolen tannophilus IFO 1007

Summary Stereoselective oxidation of (S)-isomer of rac-1-phenylethanol (1-PA) by the yeast Pachysolen tannophilus IFO 1007 immobilized into calcium-alginate gels was investigated to produce (R)-isomer. Continuous production of (R)-isomer was accomplished for more than 80 h with an enantiomeric excess of > 90% using a bioreactor of a fluidized-bed type.     

Genomic Analysis of a New Mammalian Distal-less Gene: Dlx7

We have cloned a new Dlx gene (Dlx7) from human and mouse that may represent the mammalian orthologue of the newt geneNvHBox-5.The homeodomains of these genes are highly similar to all other vertebrate Dlx genes, and regions of similarity also exist between mammalian Dlx7 and a subset of vertebrate Dlx genes downstream of the homeodomain. The sequence divergence between human and mouse Dlx7 in these regions is greater than that predicted from comparisons of other vertebrate Dlx genes, however, and there is little sequence similarity upstream of the homeodomain both between these two genes and with other Dlx genes. We present evidence for alternative splicing of mouseDlx7upstream of the homeodomain that may account for some of this divergence. We have mapped humanDLX7distal to the 5′ end of the HOXB cluster at an estimated distance of between 1 and 2 Mb by FISH. Both the human and the mouse Dlx7 are shown to be closely linked to Dlx3 in a convergently transcribed orientation. These mapping results support the possibility that vertebrate distal-less genes have been duplicated in concert with the Hox clusters.