Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0392674 (exhaustion)
 13,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In suckling hyperphenylalaninemic (hyper-Phe) rats, all essential amino acids including tryptophan are depleted in the blood. The inadequate supply of Trp to the developing brain leads to a decline of Trp, of serotonin, and of 5-hydroxyindoleacetic acid. The exhaustion of amino acids in both blood and brain can be restored by administration of Lys. Even though Phe is still elevated in blood and brain, Trp, serotonin and 5-hydroxyindoleacetic acid, are no longer depleted in the brain. This observation contradicts the idea that the serotonin deficit in the developing hyper-Phe brain is caused by competitive uptake inhibition of tryptophan or by the interference of Phe metabolites with the formation of serotonin. Increased accumulation of all large neutral amino acids in peripheral tissues and an impeded intestinal amino acid transport in suckling hyper-Phe rats appear to be responsible for the deficient supply of other amino acids, including Trp, to the developing brain. The availability of Lys for developing extraintestinal tissues seems to be involved in the regulation of intestinal amino acid transport.
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PMID:The depletion of tryptophan and serotonin in the brain of developing hyperphenylalaninemic rats is abolished by the additional administration of lysine. 243 75

The extracellular levels of the dopamine (DA) metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the medial preoptic area (MPOA) of male rats were monitored during unrestricted copulation, the ensuing state of sexual refractoriness and the resumption of mating activity. MPOA dialysates were collected from the same animal during four consecutive days. In the first day the subjects were allowed to copulate until reaching a satiation criterion. That was associated with a marked increase in the dialysate levels of the three metabolites assessed. During the next two days the animals remained sexually inactive when exposed to receptive females. Their basal levels of DOPAC and HVA were elevated, whereas those of 5-HIAA remained as low as in the first session. During the non-mating exposure to receptive females there were only minor changes in the three metabolites. By the fourth day, just before the animals resumed copulation, the basal levels of the DA metabolites, especially HVA, had decreased to values closer to those found in the first day. When they mated again to exhaustion the levels of DOPAC, HVA, and 5-HIAA increased as in the first session. The neurochemical changes found during the intervening state of sexual inactivity (i.e. increased levels of DA metabolites) are reminiscent of the effects of DA receptor blockers, which suggests a possible neurochemical mechanism for sexual refractoriness.
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PMID:Neurochemical correlates of sexual exhaustion and recovery as assessed by in vivo microdialysis. 754 Sep 27

Previous neurochemical studies have reported different pattern of 5-HT release during exercise varying across either exercise conditions or forebrain sites. This in vivo microdialysis study is the first to examine the impact of an acute intensive treadmill running (2 h at 25 m.min(-1), which is close to exhaustion time), on extracellular 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in two different brain areas in rats, the ventral hippocampus and the frontal cortex. Hippocampal and cortical 5-HT levels increased significantly after 90 min of exercise and were maximal in the first 30 min of recovery. Thereafter, cortical 5-HT levels followed a rapid and significant decrease when hippocampal levels are still maximal. During exercise, changes in extracellular 5-HIAA levels paralleled 5-HT changes, but showed no difference between the two brain areas during recovery. Thus, an intensive exercise induces a delayed increase in brain 5-HT release but recovery seems to display site-dependent patterns.
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PMID:Site-dependent effects of an acute intensive exercise on extracellular 5-HT and 5-HIAA levels in rat brain. 1124 43