In the rat, prolonged exposure to ethanol (ETOH) vapor induced an acquired increase in tolerance. After a single ETOH administration, the duration of recovery was decreased by 20% as compared to control animals and the rate of ETOH elimination from blood was increased by 27%. From the data obtained on liver enzymes--alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and superoxide dismutase (SOD)--it is suggested that the increased ALDH activity would be the consequence of an increased formation of the product of ETOH oxidation, the acetaldehyde. This over-production would not be accounted for by ADH. It is assumed that among others, the coupled reaction SOD-catalase would represent a possible alternate pathway. Data on Drosophila demonstrate that initial tolerance to ETOH is well correlated with ADH activity. It is suggested that ETOH metabolites (mainly acetaldehyde) would act also as determinant of this initial tolerance. The value of Drosophila as animal model for the study of behavioral and biochemical correlates of initial tolerance is discussed.

Alcohol Oxidoreductases↗

PubMed1980

Effects of sodium n-dipropylacetate, muscimol hydrobromide and (R,S) nipecotic acid amide on isolation-induced aggressive behavior in mice.

An inhibitor of GABA-T (sodium n-dipropylacetate), a GABA agonist (muscimol hydrobromide) and an inhibitor of GABA uptake (R,S) nipecotic acid amide were administered to DBA/2 isolated aggressive mice throughout three successive daily experimental sessions. Aggressive responses, measured by an automated device, were inhibited by the highest doses of the three drugs in each daily session. At the lowest doses, sodium, n-dipropylacetate and nipecotic acid amide failed to inhibit aggression in the first session while they were effective in the subsequent sessions. Muscimol was effective in the first session but did not differ significantly from saline in the second and third session. The highest doses of these three drugs did not affect spontaneous motor activity, indicating that the observed drug effects are rather specific.

Aggression↗

PubMed1980

Synthesis of taurine in rat liver and brain in vivo.

The in vivo formation of taurine and the analysis of labeled taurine precursors was examined in rat brain and liver at different times after an intracisternal injection of [35S]cysteine and an intraperitoneal injection of [3H]cysteine, simultaneously administered. The distribution pattern of radioactivity was similar in liver and brain. Most of the labeling in both organs (85% in brain and 80% in liver) was recovered in glutathione (oxidized and reduced), cysteic acid, cysteine sulfinic acid, hypotaurine, cystathionine, and a mixed disulfide of cysteine and glutathione. The relative rates of labeling of cysteine sulfinic acid and taurine in liver and brain suggest than in vivo, liver possesses a higher capacity for taurine synthesis than brain. A small amount of [3H]taurine was detected in brain after intra peritoneal injection of [3H]cysteine. The time of appearance of this [3H]taurine as well as the fact that it occurs when [3H]cysteine is not detectable in brain or plasma suggests that it was probably not synthesized in brain from labeled precursors but formed elsewhere and transported into the brain through an exchange process.

Animals↗

PubMed1980

In vitro protein synthesis activity of poly(A) RNA from neuroblastoma cells.

Protein synthesis activity of poly(A) RNA from M1 neuroblastoma cells was studied in a reticulocyte cell-free system. The activity of poly(A) RNA from M1 cells "differentiated" morphologically by bromodeoxyuridine was compared with that of proliferating cells. Poly(A) RNA from differentiated cells was about 10% more active than the corresponding RNA from proliferating cells. The products synthesized in vitro were fractionated by polyacrylamide gradient gel electrophoresis. A 420,000-dalton band was present in the translation products programmed by differentiated cell poly(A) RNA; it was absent in the translation products programmed by proliferating cell poly(A) RNA.

Animals↗

PubMed1980

Regional distributions of gamma-aminobutyric acid (GABA), glutamate decarboxylase (GAD), and gamma-aminobutyrate transaminase (GABA-T) in the central nervous brains of C57/BR, C3H/He, and F1 hybrid mice.

The distributions of gamma-aminobutyric acid (GABA), glutamate decarboxylase (GAD), and gamma-aminobutyrate transaminase (GABA-T) have been studied in various brain areas of mice. These neurochemical markers, which are related to inhibitory neurotransmission, were investigated in different inbred strains of mice (C3H/He, C57/BR, and their F1 hybrids). The regional distributions of GABA, GAD activity, and GABA-T activity in adult mice of these three strains were quite similar. No significant differences were found in any brain area for GAD or GABA-T activity. However, significant differences in GABA level were found in several brain areas among these strains of mice, especially in hypothalamus, hippocampus, olfactory bulb, and occipital cortex. These results provide further information to the possible influence of the GABAergic system in these brain areas.

4-Aminobutyrate Transaminase↗

PubMed1980

Effect of ethanol on superoxide dismutase activity in cultured neural cells.

Superoxide dismutase (EC 1.15.1.1) activity was investigated in several types of neural cells cultivated in the presence of 100 mM ethanol. Superoxide dismutase was inhibited by acute treatment with ethanol. Chronic treatment with ethanol specifically inhibited superoxide dismutase in glial cells. In all instances withdrawal of ethanol produced a quick return to control values. Inhibition of superoxide dismutase by ethanol may increase toxic oxygen radicals in nervous tissue.

Animals↗

PubMed1980

Development of [3H]muscimol binding to subcellular particles of a culture of mouse brain.

"Specific" binding of [3H]muscimol (11.5 nM) related to GABA receptors, occurred in subcellular particles prepared from 4-, 8-, and 12-day cultures of embryonic (14- to 15-day-old) mouse cerebrum, but not to particles prepared from 20- to 45-day cultures. Phase-contrast microscopy revealed that the presence of neuronal elements (neuroblasts, neurites) paralleled the binding of [3H]muscimol. Further evidence is thus provided for using high-affinity [3H]muscimol binding as a "neuronal marker."

Animals↗

PubMed1980

Study of some enzyme activities in cultured chick embryo brain nerve cells treated by chick embryo brain extracts.

Brain extracts from 8-day-old chick embryos have been shown to influence morphological development of dissociated brain cells from 7-day-old chick embryos in culture. Stimulatory effects on size of the neuronal somas and on growth of long processes were observed by adding the cytosol of the brain extract or the dialysate of the cytosol. These morphological changes parallel modifications of various enzyme activities according to the age of the cultures. Adenyl cyclase, (Na+,K+)- and Mg2+-ATPase, 5'-nucleotidase, choline acetyltransferase, and acetylcholinesterase activities were studied between 5 and 14 days of culture. Adenyl cyclase activity was strongly stimulated at 8 days by both extracts. (Na+,K+)- and Mg2+-ATPase activities were stimulated in 8-day-old cultures only by the dialysate. 5'-Nucleotidase activity was stimulated in 8-day-old cultures by the dialysate and in 11-day-old cultures by both extracts. Choline acetyltransferase activity was stimulated by the cytosol in 8-day-old cultures and by the dialysate in 11-day-old cultures. The total acetylcholinesterase activity was higher in 8-, 11-, and 14-day-old cultures treated with the cytosol. When the cells were treated with the dialysate, the activity was only higher in 14-day-old cultures. We also found that following the addition of brain extracts, the specific activity of the enzymes we studied was enhanced and became close to the values found in vivo during embryogenesis. Thus in parallel to the morphological modifications observed in nerve cell cultures treated by embryo brain extracts, biochemical variations especially involved in synaptogenesis and membrane development could be measured.

Acetylcholinesterase↗

PubMed1980

Development of glial cells in primary cultures: energy metabolism and lactate dehydrogenase isoenzymes.

Primary cultures of glial cells prepared from brains of newborn rats were grown for periods of 1-5 weeks. After a proliferative phase of between 2 and 3 weeks, the cultures were maintained in stationary phase, during which a significant increase of oxygen consumption and of the activities of lactate dehydrogenase, succinate dehydrogenase, and mitochondrial glycerolphosphate dehydrogenase could be observed. Furthermore, qualitative changes in the lactate dehydrogenase isoenzyme pattern were found with time, characterized by a shift toward an enhanced synthesis of H subunits. A similar development was found in comparing the LDH isoenzyme pattern in the brain of 15-day-old rat embryo with those of newborn and adult rat brains. It is suggested that some aspects of maturation of glial cells in culture are comparable to those occurring in whole brain in vivo, namely a shift towards an enhanced aerobic metabolism.

Animals↗

PubMed1980

Brain nucleic acids and protein in various neurological mutant mice.

A study was made to compare alterations in the cerebral contents of nucleic acids and protein of several mouse strains affected by different neurological mutations: jimpy, msd, quaking, reeler, weaver, and dwarf. In normal and affected jimpy and msd mice the brain components analyzed were very similar. On the other hand, the cerebral hemispheres of quaking mice showed significant decreases in total RNA and DNA, when compared with those of normal littermates. In the affected reeler and weaver mice, total protein, RNA, and DNA in the cerebellum differed markedly from controls. Protein decreased slightly, whereas nucleic acids showed no significant variation in the cerebral hemispheres of the same mutants. The cerebella and cerebral hemispheres of affected dwarf mice had wet weights and total protein contents that were about 20% lower than those of their controls; DNA did not vary significantly in the various brain regions analyzed. The decrease of DNA we report in reeler and weaver mutant cerebellum in toto quantifies the lack of cell number, in contrast to histological studies which give only semiquantitative information.

Animals↗

PubMed1980

Purification and characterization of a nicotinamide deamidase released into the growth medium of neuroblastoma in vitro.

Nicotinamide deamidase (nicotinamide amidohydrolase, EC 3.5.1.19) has been demonstrated in the conditioned growth medium of the M1 clonal cell line of mouse C1300 neuroblastoma. The enzyme has been purified 1200-1500-fold by Sephadex G25, hydroxyapatite, DEAE-cellulose, Sephadex G200 and NAD-Sepharose column chromatographies. The purified protein was characterized by polyacrylamide gel electrophoresis under non-denaturing and denaturing conditions. The apparent molecular weight has been estimated to be 230,000, and the subunits had respective molecular weights of 65,000 and 50,000. Histidine was the only NH2-terminal amino acid found. The enzyme is a glycoprotein; mannose and N-acetyl-glucosamine have been identified. The effects of various ions on its activity have been investigated. The enzyme has a Km for nicotinamide in the order of 10(-6) M, a pH optimum of 7.2 and a pHi of 5.4. It is inhibited by heating and by sulfhydryl reagents. The existence of a nicotinamide deamidase with a high affinity for nicotinamide favors the operation of the Preiss-Handler pathway in M1 cells cultured in vitro. We found an induction of nicotinamide deamidase and a cellular increase of NAD with a higher nicotinamide supply and a repression of the released enzyme with supplying NAD in the nutrition medium of M1 cell cultures.

Amidohydrolases↗

PubMed1980

Distribution of enzymes of cGMP metabolism in glomeruli and tubules isolated from normal and nephrotic rat kidney cortex.

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3',5'-Cyclic-GMP Phosphodiesterases↗