Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Young Bobwhite quail (Colinus virginianus) were fed low and adequate protein purified diets with and without excess methionine to evaluate factors affecting methionine toxicity. Growth of quail fed an adequate protein (27%) diet, without supplemental glycine, was depressed by 1.75% and 2.25% excess methionine. Supplemental glycine (.3%) alleviated growth depression caused by 2.25% excess methionine. Quail fed 1.75% and 2.25% excess methionine developed signs of toxicity characterized by weakness, a lowered, outstretched neck when moving, and ataxia. In addition, quail would fall on their sides when disturbed and spin with their heads retracted. These conditions were transient in nature. Growth of quail fed a low protein (18.9%) diet was depressed by 1% and 1.5% excess methionine and DL-homocystine. Quail fed 1% and 1.5% excess methionine in this diet also developed signs of toxicity, the incidence of which was greater and the duration longer than occurred with quail fed adequate protein. Supplementing a low protein (20.15%) diet with .3% or .6% glycine or threonine or a combination of these amino acids did not alleviate growth depression caused by 1.5% excess methionine; however, 2% and 3% supplemental glycine were somewhat effective. Supplements of glycine (2%, 3%) and threonine (1%) completely reversed growth depression from 1% excess methionine but did not influence growth of controls, indicating that both amino acids counteract methionine toxicity. Both glycine and threonine alone improved growth by about the same extent in diets with 1% or 1.5% excess methionine; however, these amino acids alleviated less than 30% of the growth depression resulting from 1.5% excess methionine. The effectiveness of glycine in alleviating methionine toxicity in a low protein diet was decreased, and hemoglobin levels were depressed with 1.5% excess methionine compared to less amounts.
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PMID:Factors influencing methionine toxicity in young bobwhite quail. 678 33

Experiments were conducted to determine the metabolic fate of threonine in chicks fed threonine-imbalanced diets. Threonine imbalance was produced by the addition of 3% serine to a threonine-limited diet, and prevented by the addition of 0.2% threonine to the diet. Serine decreased plasma and liver free threonine concentrations, and increased hepatic threonine dehydrogenase and threonine aldolase activities. All changes, including reduced food intake, appeared to occur within 1 day of feeding the imbalanced diet. Despite the decrease in free threonine concentrations and the increase in threonine aldolase and threonine dehydrogenase activities, net threonine catabolism was not markedly increased. This was evidenced by similar amounts of 14CO2 exhaled by chicks fed control and imbalanced diets containing L-[U-14C] threonine, and by similar growth of chicks that were forced-fed both diets to maintain equivalent food intake. It is possible that increases in threonine catabolism contribute to depressions of plasma and tissue threonine concentrations. However, the growth depression caused by serine-induced threonine imbalance is due to depressed food intake.
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PMID:Threonine metabolism of chicks fed threonine-imbalanced diets. 681 40

Many polar fishes synthesize a group of eight glycopeptides that exhibit a non-colligative lowering of the freezing point of water. These glycopeptides range in molecular weight between 2600 and 33 700. The largest glycopeptides [1-5] lower the freezing point more than the small ones on a weight basis and contain only two amino acids, alanine and threonine, with the disaccharide galactose-N-acetyl-galactosamine attached to threonine. The small glycopeptides, 6, 7, and 8, also lower the freezing point and contain proline, which periodically substitutes for alanine. Glycopeptides with similar antifreeze properties isolated from the saffron cod and the Atlantic tomcod contain an additional amino acid, arginine, which substitutes for threonine in glycopeptide 6. In this study we address the question of whether differences in amino acid composition or molecular weight between large and small glycopeptides are responsible for the reduced freezing point depressing capability of the low molecular weight glycopeptides. The results indicate that the degree of amino acid substitutions that occur in glycopeptides 6-8 do not have a significant effect on the unusual freezing point lowering and that the observed decrease in freezing point depression with smaller glycopeptides can be accounted for on the basis of molecular weight.
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PMID:Relationship of amino acid composition and molecular weight of antifreeze glycopeptides to non-colligative freezing point depression. 711 72

Long-term potentiation (LTP) is a synaptic mechanism thought to be involved in learning and memory. Long-term depression (LTD), an activity-dependent decrease in synaptic efficacy, may be an equally important mechanism which permits neural networks to store information more effectively. One form of LTD that has been observed in the hippocampus requires activation of postsynaptic NMDA (N-methyl-D-aspartate) receptors, a change in postsynaptic calcium concentration, and activation of postsynaptic serine/threonine protein phosphatase 1 (PP1) or 2A (PP2A). The mechanism by which PP1 or PP2A is regulated by synaptic activity is unclear because these protein phosphatases are not directly influenced by calcium concentration. LTD induction may require activation of a more complex protein phosphatase cascade consisting of the Ca2+/calmodulin-dependent protein phosphatase, calcineurin, its phosphoprotein substrate, inhibitor-1, and PP1. We tested this hypothesis using calcineurin inhibitors as well as different forms of inhibitor-1 loaded into postsynaptic cells. Our results suggest a signalling pathway in which calcineurin dephosphorylates and inactivates inhibitor-1. This in turn increases PP1 activity and contributes to the generation of LTD.
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PMID:Involvement of a calcineurin/inhibitor-1 phosphatase cascade in hippocampal long-term depression. 751 79

Using guinea-pig hippocampal slices, we determined the amount of various amino acids released into the medium during deprivation of oxygen and glucose. Within 10 min of slices being deprived of O2 and glucose, the amounts of serine, aspartate, alanine, glycine, GABA, taurine and threonine released into the medium increased up to 1.7 (serine), 1.6 (aspartate), 1.6 (alanine), 1.9 (glycine), 2.0 (GABA), 1.4 (taurine) and 1.8 (threonine) times the control levels, respectively. The amount of serine released 10 min after O2 and glucose deprivation was four times as great as that of glutamate. The dose-response effects of glutamate and serine were studied on the population spikes evoked in the granular cell layer. Bath application of 100 microM serine elevated the amplitude of the population spike to 117% and at 10 mM depressed it completely. The dose-response curve for glutamate displayed a similar pattern but the effectiveness was 10 times higher than that of serine. The combined application of glutamate (300 microM) and serine (2 mM) produced a dramatic reduction in and depression of the amplitude of the population spike, although 300 microM glutamate and 2 mM serine individually failed to show a significant effect. The population spike was depressed by the addition of 1 mM glutamate but, after washing, it recovered completely. On the other hand treatment with 1 mM glutamate together with 5 mM serine caused no recovery of the population spike even after removal of the agents.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serine released from hippocampal slices during deprivation of oxygen and glucose enhances the effects of glutamate on neuronal function. 810 49

We have investigated the characteristics and mechanism of activity-dependent decreases in synaptic effectiveness in visual cortex. Repetitive, low-frequency stimulation (LFS) of either layer IV or the white matter of visual cortical slices was shown to result in a long-term depression (LTD) of intra- and extracellularly recorded synaptic responses in layer III. In preparations in which responses to stimulation of two independent pathways could be monitored, LFS of one pathway produced LTD of responses to test stimulation of that input only, showing that this form of LTD is homosynaptic. This form of LTD was dependent on the frequency and/or pattern of conditioning stimulation and on activation of NMDA receptors. Okadaic acid, an inhibitor of protein phosphatases 1 and 2a, inhibited LTD, but had no effect on induction of long-term potentiation. In all of these respects, LFS-induced LTD in visual cortex closely resembles what has been recently documented in hippocampus. The combined data support a model in which LTD is triggered by a modest elevation in postsynaptic Ca2+ and activation of protein-serine, threonine phosphatases.
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PMID:Homosynaptic long-term depression in the visual cortex. 818 81

The effect of adding cottonseed hulls to casein- and cottonseed-kernel-based diets on the apparent and true ileal digestibility of N and amino acids, and the proportion of this effect accounted for by condensed tannin (CT), were determined using the growing rat. Sixty rats were allocated randomly to ten semipurified diets, containing either casein (four diets) or purified unheated solvent-extracted cottonseed kernel (six diets) as the sole protein source, with Cr2O3 added as an indigestible marker. Two of the casein diets contained no hulls whilst the remaining two diets contained 70 g cottonseed hulls/kg. Two of the cottonseed-kernel-based diets contained no hulls, with two containing 23 g hulls/kg and the remaining two containing 46 g hulls/kg. For each pair of diets, PEG was either included or excluded. The effect of CT was quantified by comparing control rats (-PEG; CT acting) with PEG-supplemented rats (+PEG; CT inactivated) at each level of dietary hulls. The rats were given their respective experimental diets for 14 d. Each rat was given the food ad libitum for 10 min hourly from 08.00 to 18.00 hours. On day 14, samples of digesta were collected at death from the terminal 150 mm of ileum at 7 h from the first meal. Apparent and true ileal digestibilities were calculated for DM, N and the individual amino acids. The principal finding was that the inclusion of hulls depressed the apparent and true ileal digestibilities of N and amino acids, but with the response differing between diets. With the casein-based diet the mean apparent and true ileal amino acid digestibilities were significantly depressed from 0.89 and 0.96 to 0.85 and 0.92 respectively, by the inclusion of 70 g hulls/kg in the diet, and addition of PEG then restored these to 0.89 and 0.95. All of the depression could be explained by the CT content of the hulls. However, with the cottonseed-kernel-based diet the responses fell into three categories. The apparent and true ileal digestibilities of the essential amino acids cystine and methionine were not affected by hull addition, ileal digestibilities of leucine, isoleucine, lysine, threonine and valine were markedly depressed by hull addition with approximately 50% of the depression being explained by CT, whilst the ileal digestibilities of histidine, arginine and phenylalanine were depressed by hull addition but little or none of this effect could be explained by CT. Thus the effect of hulls on protein digestion clearly differed with source of protein. With the cottonseed-kernel-based diet it seems that components of the hulls other than CT also depressed the apparent and true ileal digestibilities of N and amino acids. The identity of these components is unknown.
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PMID:The effect of cottonseed condensed tannins on the ileal digestibility of amino acids in casein and cottonseed kernel. 869 96

The levels and possibly function of several neurotransmitters can be influenced by the supply of their dietary precursors. The neurotransmitters include serotonin, dopamine, noradrenaline, histamine, acetylcholine and glycine, which are formed from tryptophan, tyrosine, histidine, choline and threonine. Tryptophan has been tested more than the other precursors in clinical trials and is currently available in some countries for the treatment of depression. Other uses for tryptophan and the therapeutic potential of other neurotransmitter precursors have not been tested adequately. Given the relative lack of toxicity of dietary components, further clinical trials with neurotransmitter precursors should be carried out.
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PMID:Behavioral effects of dietary neurotransmitter precursors: basic and clinical aspects. 881 19

The objective of this study was to investigate the effects of nutrient density and dietary energy source on performance and immune function of weanling pigs that were either challenged or not challenged with Escherichia coli lipopolysaccharide (LPS). A basal diet was formulated to contain 14 g CP/MJ DE and 7 g lysine/100 g CP. Sulfur amino acids, threonine and tryptophan were kept constant relative to lysine. Experimental diets were mixed using 70 parts basal diet and either 30 parts starch or an isocaloric amount (14 parts) of lard. Diets were fed either for ad libitum intake or on a pair-feeding basis to evaluate effects of diet nutrient density or source of energy, respectively. On d 9 and 25, pigs were challenged i.m. with either 1 mL of a LPS solution or a control solution. Lymphocyte blastogenesis was measured 2 d after the LPS administration and antibody response to sheep red blood cells (SRBC) or ovalbumin was determined 3 d after challenge. No interactive effects on performance were observed between LPS challenge and energy density or source of energy (P > .10). Injection of LPS tended to reduce feed intake and daily gain (P < .10), but not efficiency of feed or energy utilization. Addition of fat to the diets improved feed efficiency and efficiency of energy utilization for gain (P < .05). No consistent effects of LPS challenge, energy density, or source of energy were observed for lymphocyte blastogenesis. Antibody response to ovalbumin, but not to SRBC, was decreased by fat (P < .05). Results indicate that increasing energy density of the diet did not alter the performance depression due to LPS challenge. Addition of fat to the diet improved feed efficiency and efficiency of energy conversion but may depress the humoral immune response. Effects of fat on the immune response may depend on the immune status of the pig.
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PMID:Effects of immune challenge, dietary energy density, and source of energy on performance and immunity in weanling pigs. 890 12

Calcineurin is a serine/threonine protein phosphatase 2B widely distributed in the brain. However, its role in brain function remains unknown. Recent data indicate that calcineurin can participate in long-term depression or long-term potentiation in rat hippocampus. Obviously, calcineurin can also be involved in numerous brain diseases, such as ischaemic hippocampal damage when the protein dephosphorylation system is markedly altered and hyperphosphorylation of the microtubule system in Alzheimer's disease. Besides, abnormal phosphorylation of the cytoskeletal proteins affecting the synaptic signalling can lead to different pathological disorders in the brain. In this study we analysed in more detail the localization of calcineurin in neuronal elements by using confocal microscopy and immunocytochemical approaches to record the enzyme expression in cultured rat dorsal root ganglion neurons. This is the first report showing that calcineurin immunoreactivity is highly expressed in dorsal root ganglion neurons and it is localized mainly near the inner surface of the plasma membrane. Immunostaining of these cells by anti-beta subunits of voltage-operated Ca2+ channels showed that distribution of calcium channel beta-subunit and calcineurin is very similar. Our findings confirm that the function of calcineurin can be directly connected with the activity of voltage-operated calcium channels.
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PMID:Evidence for colocalization of calcineurin and calcium channels in dorsal root ganglion neurons. 915 45


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