Age related interaction of dopamine and serotonin synthesis in striatal synaptosomes

Tyrosine hydroxylase and tryptophan hydroxylase are key rate limiting enzymes in the biosynthesis of dopamine and serotonin, respectively. Since both enzymes are active in striatum, and affected by age, this study was undertaken to investigate interaction between dopamine and serotonin synthesis in brain striatal synaptosomes of aging rat. Male Wistar rats (3 and 30 month old) were killed by decapitation and brain striatal synaptosomes were prepared by discontinuous Ficoll/sucrose gradient technique. Synaptosomes were incubated in the presence of added pargiline (monoamineoxidase inhibitor), dopamine or serotonin synthesized during 25 min was measured by HPLC, employing electrochemical detection. Dopamine synthesis in synaptosomes prepared from young animals was markedly inhibited by addition of 5 μM serotonin concentrations (30) and increasing serotonin concentrations up to 50 μM caused only a smaller additional inhibition. Dopamine synthesis in synaptosomes obtained from old rats was significantly lower than that of youg animals and addition of serotonin concentrations up to 50 μM had little effect on these preparations. In case of serotonin synthesis, exogenously added 5 μM dopamine inhibited serotonin synthesis in the synaptosomes of both ages by about 40, whereas with higher concentration of dopamine (10-50 μM) the rate of inhibition was highly pronounced in old rats as compared to that of young animals. It is concluded that dopamine and serotonin interaction may be significant, and that these should be considered in long-term treatments of Parkinson's disease with L-DOPA

Evaluating the effect of foeniculum vulgar on scopolamin-induced memory impairment in Male Mice

Background: Estrogen is a steroid that regardless of its obvious effects on females’ reproductive functions shows beneficial effects on cognition. Foeniculum vulgar (fennel) has phytoestrogen compounds that might be beneficial in memory performance. This research was performed to understand if this plant can improve memory. Methods: To evaluate memory, novel object recognition task was used in male Balb-c mice, which comprised of three sections: habituation, learning trial (T1) and the test trial (T2). In this method, the difference in the exploration time between a familial (F) and a novel (N) object is taken as an index of memory performance [recognition index (RI) = (N – F)/(N + F) × 100]. Findings: Memory was harmed using 0.5 mg/kg subcutaneous scopolamine [RI (%) = -16.0 ± 3.0]. 50 mg/kg intraperitoneal fennel considerably prevented memory impairment of scopolamine [RI (%) = 35.0 ± 7.1] and this was parallel with the memory index in normal animals [RI (%) = 50.0 ± 5.8]. In addition, 0.2 mg/kg intraperitoneal 17-β estradiol showed similar results as fennel on memory protection [RI (%) = 36.0 ± 6.6]. However, the beneficial effects of fennel were impaired by prior intraperitoneal injection of 1 mg/kg tamoxifen [RI (%) = -29.0 ± 7.1]. Conclusion: The beneficial effect of fennel on memory is achieved by estrogenic receptors present in the brain; by stimulating these receptors, they could cause an increase in acetylcholine release. Therefore, it can competitively prevent the antagonizing effect of scopolamine on cholinergic receptors. © 2015, Isfahan University of Medical Sciences(IUMS). All rights reserved. Evaluating the effect of foeniculum vulgar on scopolamin-induced memory impairment in Male Mice. Available from: https://www.researchgate.net/publication/282273930_Evaluating_the_effect_of_foeniculum_vulgar_on_scopolamin-induced_memory_impairment_in_Male_Mice [accessed Jul 29, 2017]

The effects of Anethum graveolens essence on scopolamine-induced memory impairment in mice

Since Anethum graveolens (Dill) has phytoestrogenic compounds and it is proven that estrogens exert beneficial effects on cognition; the aim of this study was to understand if this plant can improve memory performance. Male Balb/c mice weighing 25-30 g were used in this study and memory was assessed by the novel object recognition task. In this method, the difference in the exploration time between a familiar object and a novel object is taken as an index of memory performance (recognition index, RI). Scopolamine significantly reduced memory index (RI = -15.5% ± 3.0). Dill essence (100 mg/kg, ip) prevented the harmful effects of scopolamine on memory (RI = 40% ± 5.5), thus RI did not differ with control animals (RI = 50% ± 5.8). In addition, 17-β estradiol also prevented memory impairment in animals (0.2 mg/kg, ip; RI = 35.8% ± 6.5). Nevertheless, the beneficial effects of dill essence were antagonized by prior injection of tamoxifen (1 mg/kg, ip; RI = -30% ± 7.8). Although phytoesrogens are not steroids, the beneficial effect of dill on memory, at least in part, may have been achieved by estrogenic receptors present in the brain. Thus dill essence could be promising in improving memory and cognition, mainly in postmenopausal women

Nerve growth factor receptors in dementia

Background/aim: Nerve growth factor (NGF) promotes the survival and differentiation of sensory and sympathetic neurons. Several studies have found that certain neuropathological factors stimulate NGF receptor expression and release the truncated nerve growth factor receptor (TNGFR) to biological fluids. The aim of this pilot study was to determine urine TNGFR levels in patients with dementia and to verify whether TNGFR can be used as a biomarker of dementia. Materials and methods: Twelve patients with dementia and 12 healthy individuals were asked to voluntarily participate in this study. Ages, sexes, and weights were matched. The first morning urine samples were collected and the concentrations of TNGFR in the urine samples were measured by fluoroimmunoassay. Results: The mean levels of TNGFR in the urine samples of the healthy control subjects and the patients with dementia were 164 +/- 23 and 341 +/- 66 ng / mg creatinine respectively. A positive relationship was found between the levels of TNGFR in different ages of both control and patient subgroups. This is consistent with the previous observations that pathological condition may stimulate the NGF receptor expression. Conclusion: These findings might be of assistance to evaluate the development of the memory loss associated with Alzheimer disease and other age-associated diseases

A Review on Ethnobotanical and Therapeutic Uses of Fenugreek (Trigonella foenum-graceum L)

Fenugreek with the scientific name of Trigonella foenum-graceum L and with leaves consisting of 3 small obovate to oblong leaflets is an annual herbaceous plant of the Fabaceae family. It is native to the eastern Mediterranean but is cultivated worldwide. This plant has medicinal alkaloids, steroid compounds, and sapogenins and many uses have been mentioned for this plant in traditional medicine. This plant has been used to ease childbirth, to aid digestion, and as a general tonic to improve metabolism. Trigonelline is considered as the most important metabolite of fenugreek, which is very effective in treating diabetes and decreasing blood cholesterol. Diaszhenin is another important compound in seeds of this plant, which is used in producing medicinal steroids like contraceptive pills. Many studies have been performed on the therapeutic effects and identification of chemical compounds of this plant. In this article, the most important biological effects and reported compounds about fenugreek seed are reviewed and its therapeutic applications are investigated. © 2015, © The Author(s) 2015

Effects of vitamin B6 on age associated changes of rat brain glutamate decarboxylase activity

Glutamate and gamma-aminobutyric acid (GABA), act as excitatory and inhibitory neurotransmitters in CNS respectively. An increase in glutamate and a decrease in GABA concentration were observed in aged brain. However, the mechanism of these changes has not been very well elucidated. Glutamate decarboxylase (GAD) catalyzes the conversion of glutamate to GABA. Since the vitamin B6 is essential for the activities of GAD, this study was undertaken to investigate the effects of vitamin B6 administration on age related changes in rat brain. The animals were injected intraperitoneally with 1, 10 and 100 mg vitamin B6 /kg body weight /day for 30 days, and specific activity of GAD was assayed in the brain supernatant. The activity of the enzyme in aged rats was significantly lower as compared to that of young animals. Vitamin B6 induced activation of the brain enzyme in both ages, but the rate of the activation was markedly pronounced in aged animals. Significant activation rate of GAD by vitamin B6 in aged rat brain may be resulted from either lower availability of vitamin B6 in aged animals, or lower affinity of the enzyme for pyridoxal -5-phosphate, which is likely to be related to conformational changes of the enzyme during aging. It is suggested that vitamin B6 may restore the activity of the brain glutamate decarboxylase in aged rat