Tryptophan overloading activates brain regions involved with cognition, mood and anxiety

ABSTRACT Tryptophan is the only precursor of serotonin and mediates serotonergic activity in the brain. Previous studies have shown that the administration of tryptophan or tryptophan depletion significantly alters cognition, mood and anxiety. Nevertheless, the neurobiological alterations that follow these changes have not yet been fully investigated. The aim of this study was to verify the effects of a tryptophan-enriched diet on immunoreactivity to Fos-protein in the rat brain. Sixteen male Wistar rats were distributed into two groups that either received standard chow diet or a tryptophan-enriched diet for a period of thirty days. On the morning of the 31st day, animals were euthanized and subsequently analyzed for Fos-immunoreactivity (Fos-ir) in the dorsal and median raphe nuclei and in regions that receive serotonin innervation from these two brain areas. Treatment with a tryptophan-enriched diet increased Fos-ir in the prefrontal cortex, nucleus accumbens, paraventricular hypothalamus, arcuate and ventromedial hypothalamus, dorsolateral and dorsomedial periaqueductal grey and dorsal and median raphe nucleus. These observations suggest that the physiological and behavioral alterations that follow the administration of tryptophan are associated with the activation of brain regions that regulate cognition and mood/anxiety-related responses.

Sex playing with the mind: effects of oestrogen and testosterone on mood and cognition

Women now spend more than 1/3 of their lives in a state of oestrogen deprivation as a result of increased life expectancy. A similar, but milder, hypogonadal state has been described for elderly men. This paper aims to review the available literature on the effects of both oestrogen and testosterone on mood and cognition. Oestrogen replacement therapy of postmenopausal women is associated with improvements in measures of well being and decline in depression scores. In addition, oestrogen seems to augment the response of postmenopausal women with major depression to antidepressant treatment. Most studies designed to investigate the impact of oestrogen on cognition indicate that replacement therapy is associated with better performance on neuropsychological tests, particularly in measures of verbal memory and fluency. The data also supports claims that oestrogen replacement therapy reduces the risk of Alzheimer's disease in later life and improves response of patients to anticholinesterase treatment. Data on the effects of testosterone is sparser. Preliminary findings suggest that testosterone therapy may improve mood when used in isolation or in association with oestrogen. The effects of testosterone on cognitive functioning are less clear - some studies indicate that the administration of testosterone to non-demented subjects is associated with better visuospatial functioning and deterioration of verbal skills. In summary, gonadal hormones seem to modulate various aspects of mental functioning. If future studies prove this to be true, hormone replacement therapy should have a major impact on the physical and mental health of older people in the years to come.

Some hitherto unreported findings on the extragenital effects of progesterone in human females--a clinical study.

40 women suffering from 'dysfunctional uterine bleeding' (DUB) were treated by progesterone (P) and signs and symptoms of 'extragenital effects' of P were noted. In addition to the previous ones reported from this laboratory, a new crop of effects, which, as far as we are aware of, have never been reported in the literature, were found and included: (i) Changes in the frequency of EEG waves, (ii) changes in the ECG (iii) changes in psychoanalytical scoring. Further (iv) with most of the parametres, the intensity of the changes showed considerable waning with passage time, despite the fact that the subjects were still receiving P. Blood P levels similarly fell considerably in the initial phase of the therapy, but recovered to some extent afterwards, despite the continuance of P therapy.

A study on CNS-side effects of mequitazine, an H1-specific antihistamine in healthy Thai volunteers.

Mequitazine is a potent, non-sedative, long-acting H1-specific antihistamine proven to be a better therapeutic drug than other conventional antihistamines. It is also reported by many authors that the drug produces less sedative or other depressive actions on the central nervous system than other antihistamines. In order to evaluate the advantage of this drug in Asian people, an assessment of side effects of mequitazine, in comparison with chlorpheniramine, on the central nervous system was done in 20 healthy Thai volunteers, 10 males and 10 females 23-39 years of age, using a double blind crossover placebo controlled trial. Various subjective tests: alertness scale rating, visual analogue scale rating as well as objective tests: card sorting, glassbead picking and estimation of reaction time, were performed. There were no significant differences in side effects on the central nervous system between mequitazine and the placebo, whereas chlorpheniramine did produce side effects.