Characterization of 5-HT transporter and receptor system in HeLaS3 cells by [(3)H]8-OH-DPAT and other serotonergic ligands.
Arch Biochem Biophys 2011;
506:66-72. [PMID:
21056540 DOI:
10.1016/j.abb.2010.10.024]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 10/27/2010] [Accepted: 10/31/2010] [Indexed: 11/22/2022]
Abstract
[(3)H]8-OH-DPAT is a selective ligand for labeling 5-HT(1A) receptor sites. In competition binding experiments, we found that classic biogenic amine transporter inhibitors displaced [(3)H]8-OH-DPAT binding at its high-affinity binding sites in HeLaS3 cells. [(125)I]RTI-55 and [(3)H]paroxetine are known to specifically label amine transporter sites, and this was observed in our cells. Displacement studies showed that 8-OH-DPAT displayed affinity in a dose-dependent manner for the labeled amine transporter sites. These data suggest that [(3)H]8-OH-DPAT binds to amine uptake sites in HeLaS3 cells. A variety of drugs targeting different classes of receptors did not significantly affect [(3)H]8-OH-DPAT binding. Moreover, we determined the specific binding effects of various serotonergic ligands (i.e. [(125)I]cyanopindolol, [(3)H]ketanserin/[(3)H]mesulergine, [(3)H]GR-65630, [(3)H]GR-113808 and [(3)H]LSD) that specifically labeled 5-HT(1), 5-HT(2), 5-HT(3), 5-HT(4) and 5-HT(5-7) receptors, respectively. It is suggested that HeLaS3 cells contain distinct types of the related to 5-HT receptor recognition binding sites. These observations could help elucidate the relevant characteristics of different types of 5-HT receptors and 5-HT membrane transporters in tumor cells and their role in tumorigenesis.
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