Effect of the edible mushroom Mycoleptodonoides aitchisonii on transient global ischemia-induced monoamine metabolism changes in rat cerebral cortex.

We performed a transient bilateral common carotid artery occlusion on rats and investigated whether feeding an aqueous extract of Mycoleptodonoides aitchisonii, an edible mushroom, affected metabolism of monoamines in the cerebral cortex, possibly protecting against ischemic damage. Seventeen days after the surgery, concentrations of the dopamine (DA) metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) and of homovanillic acid (HVA) in the cerebral cortex of the M. aitchisonii-fed group (MV) were higher than in the control ischemia (CV) group. The turnover rate of DA, which was indicated by (DOPAC+HVA)/DA, for the CV group was significantly lower than for the MV group, and the MV group value was the same rate as the sham-operated group. These data indicate that M. aitchisonii affects the dopaminergic neuronal system following brain ischemia damage in the cerebral cortex.

Anxiolytic effects of short- and long-term administration of cacao mass on rat elevated T-maze test.

We demonstrated the effects of short- and long-term administration of cacao mass on anxiety in the elevated T-maze test, which is an animal model of anxiety. In the first study, we administered cacao mass (100 mg/100 g body weight) per os and immediately performed the elevated T-maze test. Short-term cacao mass significantly abolished delayed avoidance latency compared with the control but did not change escape latency. This result suggested that cacao mass administration reduced conditional fear-relating behavior. Short-term cacao mass administration did not affect the concentration of brain monoamines, emotion-related neurotransmitters such as norepinephrine, serotonin and dopamine, in the rat brain. In the next study, we fed a cacao mass-containing diet to rats for 2 weeks and performed the elevated T-maze test. Contrary to short-term administration, chronic consumption of cacao mass tended to increase avoidance latency and did not change escape latency. Brain serotonin concentration and its turnover were enhanced by chronic consumption of cacao mass. These results suggested that chronic consumption of cacao did not affect fear-related behavior but was involved in brain monoamine metabolism. In conclusion, we suggest that short-term cacao mass consumption showed an anxiolytic effect but chronic consumption did not.

Role of estrogen receptors and aromatase on brain protein synthesis rates in ovariectomized female rats fed genistein.

We have reported that the dietary addition of genistein, a phytoestrogen found abundantly in soy products, stimulates brain protein synthesis rates of ovariectomized female rats. In the present study, we determine whether stimulation of brain protein synthesis rates in ovariectomized female rats by the dietary addition of genistein was conducted via estrogen receptors and aromatase-mediating actions. After ovariectomy, Wistar female rats were treated with genistein, the estrogen receptor antagonist ICI 182,780, and/or fadrozole a systemic aromatase inhibitor. In the cerebral cortex, the cerebellum and the hypothalamus, the fractional (Ks) rates of protein synthesis were increased by the dietary addition of genistein. These effects of genistein were inhibited by the administration of ICI 182,780 and fadrozole. However, the degrees to which ICI 182,780 and fadrozole inhibited the effects of genistein differed depending on the brain region. This result suggests that dietary genistein elevates the rate of protein synthesis in the brain of ovariectomized female rats. In addition, the estrogen receptors of the brain and the aromatase of the peripheral tissue and brain are, at least partly, related to the rate of brain protein synthesis caused by genistein.

Effects of theanine, a unique amino acid in tea leaves, on memory in a rat behavioral test.

We identified an effect of theanine on memory functions in a novel object test. Rats were fed theanine for 3 weeks ad libitum, and then they performed the object test. The theanine-fed group performed search behavior for the novel object in the test session. The results suggest that theanine-fed rats showed improved recognition, and that theanine affected learning and memory.

Administration of theanine, a unique amino acid in tea leaves, changed feeding-relating components in serum and feeding behavior in rats.

We identified an effect of gamma-glutamylethylamide (theanine) on feeding in a rat study. Oral theanine suppressed the food intake of rats. The serum glucose level did not differ from the control, but the insulin concentration was reduced and the corticosterone concentration was increased by theanine. We suggest that the effect of theanine on feeding involved hormones.

Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation.

Theanine (r-glutamylethylamide) is one of the major amino acid components in green tea. Recent studies suggest that theanine affects neurotransmission, especially inhibitory neurotransmission. In this study, we investigated whether theanine affects brain development in infant rats, because inhibitory neurotransmission is required for mature brain function. Mother rats were fed theanine ad libitum after confinement. The body weight gain rate of infants was not different from control infants. We detected theanine in the infant serum and measured neurotransmitter concentration and nerve growth factor (NGF) mRNA level in the infant rat brain. Some neurotransmitters, including dopamine, serotonin, glycine and GABA concentration, increased in the infant brain and NGF mRNA level increased in the cerebral cortex and hippocampus. However, these differences were lost by the end of nerve maturity. These results suggest that theanine enhanced synthesis of nerve growth factor and neurotransmitters during a nerve maturing period and promoted central nerve system maturation (CNS). Thus, theanine accelerated maturation. In conclusion, theanine may assist in healthy brain function development.

Effects of theanine, r-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission.

t Theanine, r-glutamylethylamide, is one of the major amino acid components in green tea and many researchers have compared theanine's effects with glutamic acid because the chemical structure is similar. In the previous study, we demonstrated that theanine can pass brain-blood barrier and may play as an agonist or an antagonist of some receptors. In this study, we investigated the effects of theanine on neurotransmitter release in the rat brain striatum by in vivo brain microdialysis and examined whether theanine affected glutamate transporters by comparing it with a glutamate transporter blocker, L-trans-Pyrrolidine-2,4-dicarboxylic acid (L-trans-2,4-PDC). Because we investigated whether the effects of theanine is similar to L-trans-2,4-PDC on the brain neurotransmission, we measured dopamine release and some amino acids release which are known as excitatory or inhibitory neurotransmitters from neurons by theanine or L-trans-2,4-PDC perfusion into the rat brain striatum. L-trans-2,4-PDC or theanine perfusion into the brain striatum caused dopamine release from dopaminergic neurons. In addition, L-trans-2,4-PDC perfusion increased glutamic acid, aspartic acid and, whereas theanine perfusion prevented aspartic acid release and increased glycine release. These results suggested that the mechanism of dopamine release caused by theanine is different from glutamate transporter blockers or glutamic acid. Further, L-trans-2,4-PDC cause excitatory neurotransmission, whereas theanine may inhibit excitatory neurotransmission and cause inhibitory neurotransmission via glycine receptors.

Enhancing effect of Mycoleptodonoides aitchisonii on synthesis of nerve growth factor and releasing dopamine in the rat brain.

The effects of edible mushroom Mycoleptodonoides aitchisonii on the synthesis of nerve growth factor (NGF) and neurotransmitter metabolism in rat brain were examined in Wistar strain rats fed a controlled diet for 14 days. Then each brain was dissected to detect the levels of neurotransmitters and NGF in various regions. Dopamine concentration in the cerebral cortex was 1.5-fold significantly increased in the M. aitchisonii feeding group than the control group. However, NGF concentration of the M. aitchisonii feeding was significantly low. NGF concentration in this remaining area of brain from where the cerebral cortex, striatum, hippocampus, cerebellum, hypothalamus and amygdala were removed was significantly higher in the M. aitchisonii feeding. At the same time, in the striatum, the dopamine metabolite DOPAC was significantly increased in the M. aitchisonii feeding. Thereafter, we measured dopamine release from striatal slices using aqueous extract of M. aitchisonii, there was an enhancing effect on dopamine release. These results suggested that M. aitchisonii has enhancing effect on the synthesis of NGF and catecholamine metabolites in the rat brain.

Mycoleptodonoides aitchisonii affects brain nerve growth factor concentration in newborn rats.

Fourteen days pregnant Wistar strain rats were fed powder or aqueous extract of the edible fungus MycoleptFodonoides aitchisonii. Nerve growth factor (NGF) concentrations were measured in the brain of newborn rats during the lactation period at 0, 7 and 14 days after the birth. Two M. aitchisonii-fed groups showed a significant increase in NGF concentrations in brain halves compared to those who were fed control feed at days 7 and 14. At day 21, NGF concentrations in the cerebral cortex and hippocampus were not significantly different among the three groups. After weaning, the young rats were fed the same test diet as their mothers. Ten days later, Morris water maze test was started. After the test, the rats were sacrificed and NGF concentrations in the cerebral cortex and hippocampus were measured. Significant NGF concentration increases were detected in the cerebral cortex for two M. aitchisonii-fed groups and in the hippocampus in the aqueous extract group. These results suggest that NGF in the brain reached the same levels by day 21, but that M. aitchisonii affected the growth rate in the lactation period. The learning test stimulated the brain and some compounds of M. aitchisonii enhanced NGF synthesis in rat cerebral cortex and hippocampus.