Serotonin {60000050}

Shared Reference Notes

• [1.1] 
  - #Bifidobacterium infantis > elevate tryptophan levels in blood plasma > influence central serotonin transmission
• - Candida, Streptococcus, Escherichia, and Enterococcus spp. can produce serotonin
• [1.2] [#Crohn’s disease, #Inflamatory bowel disease] 
  - The blood–brain barrier allows the access of #Tryptophan. - In IBD, especially in CD patients, TRP metabolism increases; consequently, the amino acid levels are reduced with respect to normal healthy individuals, and these changes correlate with the gravity of the disease. - TRP undergoes two major metabolic host pathways, the #kynurenine (KYN) and serotonin (5-HT) biosynthetic pathways, and one microbial pathway to produce #Indole and its derivatives.
• [1.3] 
  - Candida albicans, Escherichia, Streptococci, and Enterococci spp. produce serotonin (5-HT)
• [1.4] [#Parkinson’s Disease] 
  - Serotonin > protective factor of PD
• [1.5] 
  - 5-Hydroxytryptamine (serotonini) > could exert pro- or anti-inflammatory effects in the gut depending on the respective engagement of 5-HT7 versus 5-HT4 receptors.
• [1.6] [#Short Chain Fatty Acid] 
  - SCFAs > directly affect the sympathetic system > thereby increasing the release of mucosal serotonin and affecting learning and memory functions
• [1.7] [#Alzheimer’s disease] 
• [1.8] [#Antibiotic Therapy] 
  - Gut Dysbiosis > increase hypothalamic microRNA-204 (miR-204), a microRNA > reduce SIRT1 and BDNF > decrease in the sympathetic nerve activity > increase the browning of WAT > #Obesity
• [1.9] [#Colorectal cancer] 
  - #Tryptophan > serotonin > can exhibit both a protective and detrimental role. For example, activation of serotonin receptors, 5-HTR1B and 5-HTR2B stimulate tumor angiogenesis and cell proliferation. SCFAs can induce the production and release of serotonin though. In normal conditions, serotonin seems to have mainly a protective role but dysregulation of its production is linked to cancer promotion.
• - 5-HT in the body is synthesized from the essential amino acid #Tryptophan (Trp) in both the brain and gut, and the majority of it (approximately 95% of total 5-HT) resides in the digestive tract and is mostly produced and stored in enterochromaffin cells (ECs). - In the gut, 5-HT is responsible for one of the core signaling pathways, especially in modulating intestinal permeability and regulating mucosal inflammation. - 5-HT is related to colon inflammation in a DSS-induced murine colitis model, and treatment by inhibiting 5-HT production in colonic mucosa has a therapeutic outcome in ameliorating colitis-associated symptoms and inflammation
• [1.11] 
  - bacterial SCFA-#Butyrate regulates the biosynthesis of serotonin, which is responsible for initiating peristalsis.
• [1.12] [#Short Chain Fatty Acid] 
  - SCFAs, serotonin, #kynurenine, #Indole and its derivatives, and #Tryptamine, can bridge the gut and nervous system.
• [1.13] 
  - lack of gut microbiota causes changes in the expression of serotonin 5-HT1 receptors;
• [1.14] [#Celiac Disease, #Migraine] [#CGRP, #Glutamate] 
• [1.15] 
  - #Pu-erh tea could boost the #Indole and 5-hydroxytryptamine pathways of the Trp metabolism.
• - #Tryptamine induces the release of the neurotransmitter 5-HT, a serotonin of enterochromaffin cells. - 5-HT can work on the enteric nervous system to stimulate gastrointestinal motility such as #Irritable bowel syndrome (IBS)
• [1.16] 
  - A higher relative abundance of #Alistipes species has been reported in children with #Autism, pervasive developmental disorder not otherwise specified (PDD-NOS) , and depression. - #Alistipes may disrupt the gut–brain axis by decreasing serotonin (indole-positive organism) and impair cognition by producing #Propionic acid in rats.
• [1.17] [#Parkinson’s Disease] 
  - #Tryptophan, an essential amino acid only derived from microbiome or diet, is the rate limiting precursor to serotonin. #Tryptophan biosynthesis pathway was reduced in PD. - spore forming bacteria modulate serotonin production and enhance gut motility - #Constipation, a common symptom of PD, may be related to the depletion of spore forming bacteria.
• [1.18] 
  - #Tryptophan metabolites are produced via four different pathways: The serotonin pathway, the #Tryptamine pathway, the #kynurenine pathway, and the bacterial #Indole pathway.
• [1.19] 
  - #Eggerthella is involved in the synthesis of serotonin and gamma aminobutyric acid (#GABA).
• - serotonin produced by the gut cannot cross the blood-brain barrier, it can affect the blood-brain barrier permeability, which can lead to inflammation of the brain.

References Notes