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Epilepsy
Published in Divya Vohora, The Third Histamine Receptor, 2008
Divya Vohora, Krishna K. Pillai
Presynaptic H3 receptors occur both on histaminergic neurons of the CNS (autoreceptors) and on nonhistaminergic neurons of the CNS and autonomic nervous system [72]. Thus, they regulate the release of not only histamine but also other important transmitters such as norepinephrine (NE) [73], dopamine (DA) [74], 5-hydroxytryptamine (5-HT)[75], acetylcholine (Ach)[76] and gamma amino butyric acid (GABA) [47] through heteroreceptors in the CNS. Such effects of H3 heteroreceptors have been most thoroughly investigated in the mouse brain cortex where they cause inhibition of NE release [77] and in the guinea pig small intestine causing inhibition of ACh release [78]. H3 receptor antagonists have been demonstrated to enhance whereas histamine and H3 receptor agonists have been shown to reduce the release of these transmitters in in vitro studies. All these transmitters are related in some or the other way to epilepsy and epileptic seizures [57]. Although THP, an H3 receptor antagonist, was found to increase the release of GABA from the rat hypothalamus [47], RAMH, a selective agonist, inhibited the release [79]. It is needless to emphasize the importance of GABA in seizures and epilepsy. The effect of these ligands on GABA release correlates well with their effects on modulation of seizure activity. A study by Arrang et al. [80], however, demonstrated no inhibition of ACh release from rat entorhinal cortex synaptosomes following H3 receptor activation. H3 receptor antagonists also provided protection against amygdala kindling in rats [22]. A reduction in DA and NE content occurs following amygdala kindling [13]. Thus, it is possible that the protection afforded by these agents involve an indirect action through the enhancement of release of these neurotransmitters in brain. However, the dose of THP employed in the study provided protection but did not affect the brain levels of DA, 3,4-dihydroxyphenylacetic acid, 5-HT, and 5-hydoxyindoleacetic acid [23]; thus, ruling out the possibility of involvement of these neurotransmitters in the protective effect. The role for NE, however, may not be overlooked, as H3 receptors regulating the release of NE are located in the catecholaminergic nerve terminals. However, the modulation of even catecholaminergic tone was also not confirmed by in vivo studies [61]. In view of all these observations, the heteroreceptor function seems to play a minor role in contrast with the modulation of histamine release by these receptors [81].
Edible insects prevent changes to brain monoamine profiles from malnourishment in weaned rats
Published in Nutritional Neuroscience, 2023
Ella E. Bauer, Isaac Agbemafle, Manju B. Reddy, Peter J. Clark
The objective of this study was twofold. First, to evaluate monoamine-related neurochemical changes from 3 weeks and 5 weeks of protein and iron deficiency in rats spanning developmental stages of weanling to periadolescence across the hippocampus, striatum, hypothalamus, and prefrontal cortex. These brain regions were selected because they contribute to several cognitive and physiological processes that can be disrupted during malnutrition, including attention, learning, motivation, energy homeostasis, and stress response [17–19]. Second, to evaluate the influence of insect-based-diet repletion on restoring monoamine-related neurochemical profiles across the same brain regions following three weeks of protein and iron insufficiency in post-weaned rats. Cricket and palm weevil larvae diets were chosen because they are not only rich in protein and iron but are also increasing in popularity for cultivation and consumption in both developing and developed countries [6,20]. Neurochemical concentrations including 5-HT, DA, NE, epinephrine (EPI), and metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) were measured using Ultra High-Performance Liquid Chromatography (UHPLC). The results of this study provide a comprehensive assessment of markers of monoaminergic activity across weanling rat brain from malnutrition followed by insect-protein repletion, which could have implications for the nutritional and neurobiological value of edible insects.
Tryptophan-tyrosine dipeptide improves tau-related symptoms in tauopathy mice
Published in Nutritional Neuroscience, 2023
Yasuhisa Ano, Yuta Takaichi, Rena Ohya, Kazuyuki Uchida, Hiroyuki Nakayama, Akihiko Takashima
PS19 and wild-type male mice (2.5 months of age) were fed a diet containing 0 or 0.05% (w/w) tryptophan-tyrosine (Trp-Tyr) dipeptide for 6.5 months. (A)-(C) Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) per tissue gram, respectively, in the cortex. Metabolite levels were measured using a high-performance liquid chromatography-electrochemical detection system. (D) and (E) Ratios of DOPAC/DA and (DOPAC + HVA)/DA, respectively. Data are presented as the mean ± standard error of the mean (wild-type mice, n = 11; wild-type mice fed Trp-Tyr dipeptide, n = 10; transgenic control mice, n = 11; transgenic mice fed Trp-Tyr dipeptide, n = 10). p-values shown in the graph were calculated using the two-way ANOVA followed by the Tukey–Kramer test. *p < 0.05. Ctrl, control mice; Trp-Tyr, tryptophan-tyrosine-fed mice.
The role of nutrition on Parkinson’s disease: a systematic review
Published in Nutritional Neuroscience, 2023
Vittorio Emanuele Bianchi, Laura Rizzi, Fahad Somaa
In animal models, it was demonstrated that many foods rich in polyphenols exerted a neuroprotective effect. The citrus flavanone naringenin significantly increased the content of tyrosine hydroxylase (TH) in neurons, reducing the loss of DA and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brain [116]. The naringin (glycoside of naringenin) [117], flavanone glycoside found in citrus fruits − hesperidin [118], and myricitrin, derived from the root bark of Myrica cerifera, stimulated the activation of mTORC1 and TH activity [97]. Epigallocatechin-3-gallate (EGCG), [119] a major flavone in tea, curcumin had a potent antiparkinsonism effect in mice in combination with curcumin and niacin [120]. This protective effect has been suggested to be attributed to tea polyphenols’ antioxidant, anti-inflammatory, and anti-excitotoxic activity [121].