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Serotonin in the Intestinal Tract: A Synopsis
Published in T.S. Gaginella, J.J. Galligan, SEROTONIN and GASTROINTESTINAL FUNCTION, 2020
Serotonin is synthesized from tryptophan, through the sequential action of the rate-limiting enzyme tryptophan-5-hydrolase and 5-hydroxytryptophan decarboxylase. Mucosal 5-HT levels are modulated by dietary tryptophan.13,14 The levels are increased in animals by antibiotics, especially sulfonamides,15–17 and in the rat stomach after ACTH administration.18 Levels are decreased after nicotine,19 bradykinin,20 α-methyl dopa,21 reserpine,22 and steroids.23 No change in 5-HT level was found after administration of prostaglandins24 or gastrin25 in rats. The gut is more resistant than the brain to depletion by parachlorophenylalanine,26 an inhibitor of tryptophan-5-hydroxylase.
Pharmacotherapy of Neurochemical Imbalances
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Rupali Patil, Aman Upaganlawar, Suvarna Ingale
An amino acid histidine, undergoes decarboxylation in presence of histidine decarboxylase enzyme to form Histamine. It is converted to methyl histamine in presence of an enzyme imidazole N-methyl transferase or, alternatively, to imidazole acetic acid in presence of an enzyme diamine oxidase (histaminase). MAO facilitates the oxidation of methyl histamine to methyl imidazole acetic acid (Fig. 22.7; Oja and Saransaari, 2009).
Vitamins
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Found primarily in vegetables, peanuts, eggs, soy, and cereals, vitamin B6 (pyridoxal, pyridoxamine) appears to play a significant role in neuronal development. It is particularly important in the formation of pyridoxal-dependent decarboxylase, necessary for the synthesis of the neurotransmitter γ-aminobutyric acid (GABA). In fact, pyridoxine deficiencies, although rare, are characterized by unremarkable features of dermatologic, hematologic, and nervous system anomalies. Vitamin B6 deficiencies occur in individuals who are also susceptible to deficiencies of other B-vitamins, including chronic alcoholism and malabsorption syndrome. Patients receiving isoniazid, cycloserine (antituberculosis antibiotics), hydralazine (antihypertensive), and oral contraceptives are also prone to B6 deficiency. Pyridoxine is indicated solely for the management of pyridoxine deficiency states. Sensory neuropathies, ataxia, and numbness are possible in subjects receiving megadoses for several months.
Potential oral probiotic Lactobacillus pentosus MJM60383 inhibits Streptococcus mutans biofilm formation by inhibiting sucrose decomposition
Published in Journal of Oral Microbiology, 2023
Mingkun Gu, Joo-Hyung Cho, Joo-Won Suh, Jinhua Cheng
For assessment of biogenic amine produced by L. pentosus MJM60383, the decarboxylase agar plates (%) (tryptone, 0.02 g; manganese sulfate, 0.5 g; yeast extract, 0.5 g; sodium chloride, 0.25 g; glucose, 0.05 g; tween 80 g, 0.005 g; bromocresol purple, 0.1 g; magnesium sulfate, 0.005 g; ferrous sulfate, 0.2 g; thiamine, 0.001 g; dipotassium phosphate, 0.5 g; meat extract, 0.2 g; calcium carbonate, 0.004 g; ammonium citrate, 0.01 g; pyridoxal 5-phosphate, 0.006 g; agar, 20 g; distilled water, 1000 mL; pH, 5.3) were prepared by adding different amino acids (L-phenylalanine, L-histidine, L-lysine, L-tyrosine, and L-ornithine) [17]. The decarboxylase medium without amino acids supplementation served as a control. L. pentosus MJM60383 and LGG were streaked on plates and incubated at 37 ºC for 48 h. After incubation, biogenic amine production was determined by the appearance of purple color around the colony.
The clinical relationship between histamine-1 receptor antagonists and risk of cancer: a systematic review and meta-analysis
Published in Expert Review of Anticancer Therapy, 2023
Elham Bakhtiari, Nasrin Moazzen, Amir Amirabadi, Hamid Ahanchian
Wide variety of mammalian cells express histamine receptor 1. One of these cells are cluster of differentiation 4+ T helper1 (Th1) lymphocytes. It predominantly expresses in H1 receptor (H1R), while H2 receptor (H2R) expresses more in CD4 + T helper2 lymphocytes. Effect of histamine in H1R is enhancing Th1- type response. However, attenuating of both Th1 and Th2 type responses will occur by H2R [29]. Natural killer cells produce high amounts of interferon gamma (IFN-ν) after recognizing malignant cells; augmenting Th1 type, and cytotoxic T lymphocyte response [30]. One suggestion may be suppressing Th1 response by antagonizing H1R and attenuating anti-cancer activity of natural killer (NK) cells [30]. Another possible pathway, which may involve histamine in carcinogenesis, is enhancing vascular endothelial growth factor (VEGF), one of proangiogenic cytokines. It can be due to overexpression of cyclooxygenase 2 (COX2) pathway and enhanced activity of histidine decarboxylase [31,32]. Some studies exhibit higher concentration of histamine and histidine decarboxylase in breast cancer tissue [33].
A novel treatment option for intrajejunal levodopa administration
Published in Expert Review of Neurotherapeutics, 2023
In Parkinson’s disease (PD), there is a dopamine deficiency that has been well substituted since the 1960s, which allows the disease to be successfully treated [1]. Since dopamine does not cross the blood-brain barrier, levodopa (L-3,4-dihydroxyphenylalanine) is administered. As under physiological conditions a high proportion of levodopa is being metabolized into dopamine in the periphery before passing the blood-brain-barrier, the DOPA-decarboxylase inhibitors (DDI) were introduced, increasing the bioavailability of levodopa by about ten times. That is why levodopa is only given with the decarboxylase inhibitors benserazide or carbidopa in a ratio of 4 to 1 [1]. Levodopa is also degraded peripherally by the enzyme catechol-O-methyl transferase (COMT), which is why the additional administration of a COMT inhibitor has proven itself in levodopa therapy [1].