Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P46098 (5-HT3 receptor)
 2,290 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5-hydroxytryptamine3 receptor 5-HT3R has been implicated in gut and cardiac motility and in behavioral disorders. Characteristics of 5-HT3Rs appear to be heterogeneous among species, but human 5-HT3R cDNA has not been identified. We isolated a cDNA encoding 5-HT3R from human hippocampus. The mouse 5-HT3R gene has been reported to generate two alternative splicing isoforms that differ by six amino acids. All of our isolated human clones corresponded to the shorter isoform. Amino acid identities with mouse neuroblastoma N1E-115 and rat brain 5-HT3Rs were 84% for each. Southern blot analysis of human genomic DNA suggested that our cloned transcript encoded a human counterpart for the rodent 5-HT3Rs. This gene was assigned to chromosome 11 using polymerase chain reaction analysis of a human/rodent somatic cell hybrid panel. With the use of Northern blot analysis, 5-HT3R transcripts were identified in human small intestine, colon, and brain regions including hippocampus, amygdala, and striatum. In human heart, 5-HT3R expression was not detectable even with reverse transcriptase-polymerase chain reaction analysis, although it was detectable in mouse heart. Transfection of COS-1 with human 5-HT3R cDNA induced specific binding of the 5-HT3R-selective radioligand [3H]YM060. Human 5-HT3R showed typical characteristics of the 5-HT3R, but its affinity for the 5-HT3R agonist m-chlorophenylbiguanide was much lower than that of rat 5-HT3R. When injected with human 5-HT3R cRNA, the oocytes responded to 5-HT3R agonists with a rapidly developing inward current. The potency of the agonists to induce inward current paralleled that to compete with the radioligand binding, and 2-methyl-5-hydroxytryptamine, a partial agonist for mouse 5-HT3R, was a full agonist for human 5-HT3R. Our data revealed that the 5-HT3R molecule has interspecies differences in both tissue distribution and functional profile.
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PMID:Molecular cloning of human 5-hydroxytryptamine3 receptor: heterogeneity in distribution and function among species. 756 20

The serotonin 5-HT3-A receptor (5-HT3R-A) mRNA has been shown recently to be expressed as two forms (5-HT3R-AL and 5-HT3R-AS) varying by the presence or the absence of a sequence of 18 bases in the region corresponding to the second cytoplasmic domain of the receptor, and generated by alternative splicing at the level of the 3' acceptor site of exon 9. As the long form of the receptor exhibits a potential phosphorylation site that is disrupted by the alternative splicing, the hypothesis of functional identity and stochastic expression of these two variants was questioned. In the present study, we used quantitative reverse transcriptase-polymerase chain reaction to examine the possible influence of culture conditions on the expression and the alternative splicing of 5-HT3R-A mRNA in NG108-15 clonal cells. Cell differentiation induced by dibutyryl cyclic AMP or theophyllin plus prostaglandin E1 in the presence of 10% serum reduced by threefold the expression of total 5-HT3R-A mRNA, and favored the short form of the message as the ratio S/L (5-HT3R-AS mRNA/5-HT3R-AL mRNA) shifted from 2.23 to 7.33 after 9 days of treatment. Culture with 0.3% serum (instead of 10%) lowered by 10-fold the level of expression of total 5-HT3R-A mRNA, but only slightly reduced the S/L ratio. However, this ratio fell to 0.06 in the presence of 0.3% serum plus 10 ng/ml basic fibroblast growth factor. These results demonstrate that external factors can influence the differential expression of the two variants of the 5-HT3R-A in NG108-15 cells. Appropriate culture conditions for the almost exclusive expression of 5-HT3R-AS mRNA or 5-HT3R-AL mRNA in NG108-15 cells should allow the identification of possible differences in the respective functional properties of each of these two forms of the native 5-HT3 receptor.
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PMID:Differentiation alters the expression of the two splice variants of the serotonin 5-HT3 receptor-A mRNA in NG108-15 cells. 759 74

The type 3 serotonin (5-HT3) receptor is the only ligand-gated ion channel receptor for serotonin in vertebrates. Two 5-HT3 receptor subunits have been cloned, subunit A (5-HT3A) and subunit B (5-HT3B). We used in situ hybridization histochemistry and reverse transcriptase-PCR amplification to demonstrate that 5-HT3A subunit transcripts are expressed in central and peripheral neurons. In contrast, 5-HT3B subunit transcripts are restricted to peripheral neurons. Thus, the prevalent form of 5-HT3 receptor synthesized within the CNS lacks the 5-HT3B subunit. Because coexpression of 5-HT3A and 5-HT3B subunits produces heteromeric 5-HT3A/3B receptors with properties that differ from those of 5-HT3A homomeric receptors, we investigated possible coexpression of both subunits at the cellular level. We found that near to 90% of all 5-HT3B expressing neurons coexpress the 5-HT3A subunit in superior cervical and nodose ganglia (NG). In addition, there is a cellular population that expresses only the 5-HT3A subunit. Therefore, peripheral neurons have the capacity to synthesize two different 5-HT3 receptors, 5-HT3A+/3B- and 5-HT3A+/3B+ receptors. We also determined that neurons of NG projecting to the nucleus tractus solitarium and those of dorsal root ganglia projecting to superficial layers of the spinal cord express 5-HT3A or 5-HT3A/3B subunits. Thus, presynaptic 5-HT3 receptors containing the 5-HT3B subunit might be present in these target brain areas. The compartmentalized structural composition of the 5-HT3 receptor may be the basis of functional diversity within this receptor. This raises the possibility that 5-HT3 receptors participating in sympathetic, parasympathetic and sensory functions may be functionally different from those involved in cognition and emotional behavior.
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PMID:Differential composition of 5-hydroxytryptamine3 receptors synthesized in the rat CNS and peripheral nervous system. 1215 52