Search results for "5-HT"
showing 10 items of 134 documents
Effects of Hypericum Extract on the Expression of Serotonin Receptors
1994
The influence of hypericum extract LI 160 on the expression of serotonin receptors was investigated using a neuroblastoma cell line to establish a model for the regulation of neurotransmitters by immunologically active compounds such as cytokines. The cells were incubated with hypericum extract LI 160 in kinetic form for 2, 4, 6, 8, and 10 hours, then washed. The serotonin receptor expression analysis was compared to that of a placebo control solution. The neuroblastoma cells showed a clearly reduced expression of the serotonin receptors under treatment with hypericum extract. First stimulation experiments with interleukin-1 (IL-1) and hypericum extract suggest that a further reduction of …
Bradykinin-induced Internalization of the Human B2Receptor Requires Phosphorylation of Three Serine and Two Threonine Residues at Its Carboxyl Tail
1999
The binding of bradykinin (BK) to B2 receptor triggers the internalization of the agonist-receptor complex. To investigate the mechanisms and the receptor structures involved in this fundamental process of receptor regulation, the human B2 receptor was mutated within its cytoplasmic tail by complementary strategies of truncation, deletion, and amino acid substitution. Ligand binding, signal transduction, internalization as well as phosphorylation were studied for the mutated receptors expressed in COS, CHO, and HEK 293 cells. Truncation of 44 out of 55 amino acid residues of the receptor's cytoplasmic tail corresponding to positions 321-364 did not alter the kinetics of BK binding and the r…
Natural selection constrains personality and brain gene expression differences in Atlantic salmon (Salmo salar).
2015
ABSTRACT In stream-spawning salmonid fishes there is a considerable variation in the timing of when fry leave the spawning nests and establish a feeding territory. The timing of emergence from spawning nests appears to be related to behavioural and physiological traits, e.g. early emerging fish are bolder and more aggressive. In the present study, emerging Atlantic salmon (Salmo salar L.) alevins were sorted into three fractions: early, intermediate and late emerging. At the parr stage, behaviour, stress responses, hindbrain monoaminergic activity and forebrain gene expression were explored in fish from the early and late emerging fractions (first and last 25%). The results show that when s…
The relationship between genetic risk variants with brain structure and function in bipolar disorder: A systematic review of genetic-neuroimaging stu…
2017
Genetic-neuroimaging paradigms could provide insights regarding the pathophysiology of bipolar disorder (BD). Nevertheless, findings have been inconsistent across studies. A systematic review of gene-imaging studies involving individuals with BD was conducted across electronic major databases from inception until January 9th, 2017. Forty-four studies met eligibility criteria (N = 2122 BD participants). Twenty-six gene variants were investigated across candidate gene studies and 4 studies used a genome-wide association approach. Replicated evidence (i.e. in >2 studies) suggests that individuals with BD carrying the BDNF Val66Met risk allele could have reduced hippocampal volumes compared …
A Role for the β1-β2Loop in the Gating of 5-HT3Receptors
2005
Based on theTorpedoacetylcholine receptor structure, Unwin and colleagues (Miyazawa et al., 2003; Unwin, 2005) hypothesized that the transduction of agonist binding to channel gate opening involves a “pin-into-socket” interaction between αV46 at the tip of the extracellular β1-β2loop and the transmembrane M2 segment and M2-M3 loop. We mutated to cysteine the aligned positions in the 5-HT3Aand 5-HT3Bsubunit β1-β2loops K81 and Q70, respectively. The maximal 5-HT-activated currents in receptors containing 5-HT3A/K81C or 5-HT3B/Q70C were markedly reduced compared with wild type. Desensitization of wild-type currents involved fast and slow components. Mutant currents desensitized with only the f…
Serotonin–dopamine interaction: an overview
2008
Central serotonergic and dopaminergic systems play a critical role in the regulation of normal and abnormal behaviours. Moreover, recent evidence suggests that the dysfunction of dopamine (DA) and serotonin (5-hydroxytriptamine, 5-HT) neurotransmission might underlie the pathophysiology of neuropsychiatric disorders, including depression, schizophrenia, attention deficit hyperactivity disorders, drug abuse, Gilles de la Tourette's syndrome and Parkinson's disease.
Serotonin receptor agonist treatment induces transactivation of fibroblast growth factor receptor-1 (FGFR1) tyrosine kinase in the rat hippocampal ne…
2010
Over the past decade, many examples of activation of receptor tyrosine kinases in response to G-protein coupled receptor signaling have been reported, indicating that there are alternative modes of receptor tyrosine kinase activation (transactivation) in the absence of neurotrophic factor binding. In the present work, we aimed to examine if 5-HT receptor subtype activation may induce fibroblast growth factor receptor-1 (FGFR1) phosphorylation through transactivation of tyrosine kinase. The study has been performed in young adult rats treated with the selective 5-HT1A receptor agonist 8-OHDPAT at the dose of 0.4 mg/kg/i.p.. FGFR1 phosphorylation was evaluated by immunoprecipitation and weste…
A mutation in the second intracellular loop of the pituitary adenylate cyclase activating polypeptide type I receptor confers constitutive receptor a…
2000
AbstractThe pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor belongs to the glucagon/secretin/vasoactive intestinal polypeptide (VIP) receptor family. We mutated and deleted an amino acid residue (E261) which is located within the second intracellular loop of the rat PACAP type I receptor and which is highly conserved among the receptor family. The wild-type receptor and the mutant receptors were efficiently expressed at the surface of COS-7 cells at nearly the same level and revealed the same high affinity for the agonist PACAP-27. The cAMP contents of COS cells transfected with the E261A, E261Q, and the deletion mutant receptor were 4.6-, 5.7-, and 6.7-fold highe…
Regulation of serotonin release from the intestinal mucosa.
1991
Summary In the mammalian intestine serotonin (5-hydroxytryptamine, 5-HT) is present in high concentrations in the enterochromaffin cells. The release of 5-HT from the intestinal mucosa is regulated by a complex pattern of neuronal and humoral inputs to the enterochromaffin cells. The enterochromaffin cells appear to be endowed with different inhibitory ( α 2 -adrenoceptors, GABA A - and GABA B -receptors, histamine H 3 -receptors, receptors for vasoactive intestinal polypeptide and somatostatin) as well as stimulatory receptors ( β -adrenoceptors, muscarine and nicotine receptors). The physiological significance of this complex system of receptors is suggested by experiments which demonstra…
Serotonin transporter gene polymorphism in eating disorders: Data from a new biobank and META-analysis of previous studies.
2016
Objectives Growing interest focuses on the association between 5-HTTLPR polymorphism and eating disorders (ED), but published findings have been conflicting. Methods The Italian BIO.VE.D.A. biobank provided 976 samples (735 ED patients and 241 controls) for genotyping. We conducted a literature search of studies published up to 1 April 2015, including studies reporting on 5HTTLPR genotype and allele frequencies in obesity and/or ED. We ran a meta-analysis, including data from BIO.VE.D.A. – comparing low and high-functioning genotype and allele frequencies in ED vs. controls. Results Data from 21 studies, plus BIO.VE.D.A., were extracted providing information from 3,736 patients and 2,707 co…