These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Serotonergic signalling between thyroid cells: protein kinase C and 5-HT2 receptors in the secretion and action of serotonin.
    Author: Tamir H, Hsiung SC, Yu PY, Liu KP, Adlersberg M, Nunez EA, Gershon MD.
    Journal: Synapse; 1992 Oct; 12(2):155-68. PubMed ID: 1336223.
    Abstract:
    Parafollicular (PF) cells of the thyroid gland are neural crest derivatives, which costore the neurotransmitter, 5-hydroxytryptamine (5-HT) with calcitonin. PF cells are located adjacent to follicular (F) cells within the basement membrane of thyroid follicles. It has been proposed that 5-HT serves an intercellular signalling function in the thyroid and that F cells are its target. This proposal was tested by using cell lines derived from PF (medullary thyroid carcinoma [MTC]) and F (FRTL-5) cells to study the mechanisms that mediate the secretion and action of 5-HT. Secretion of 5-HT by MTC cells was evoked by thyroid stimulating hormone, thyrotropin (TSH), elevated extracellular calcium (increases [Ca2+]e), or by agents that increase intracellular cAMP (increases [cAMP]i). When protein kinase C (PKC) was down-regulated by prolonged treatment of MTC cells with phorbol 12-myristate 13-acetate (PMA), or PKC was inhibited by staurosporin, the TSH- or PMA-evoked secretion of 5-HT was blocked; however, interference with PKC function did not affect 5-HT secretion evoked by increases [Ca2+]e or increases [cAMP]i. In the putative targets, FRTL-5 cells, 5-HT increased the turnover of phosphoinositides (PI), cytosolic calcium (increases [Ca2+]i), increases [cAMP]i, and biphasically modified the effect of TSH on cAMP. All of these 5-HT effects were inhibited by 5-HT2 receptor antagonists (spiperone and ketanserin) and by pertussis toxin (PTx), suggesting that the actions of 5-HT are mediated by 5-HT2 receptors, which are coupled to a G protein. This suggestion was supported by the following additional observations: FRTL-5 membranes bound the 5-HT2 agonist, [125I]2,5-dimethoxy-4-iodophenylisopropylamine ([125I]-DOI), and anti-idiotypic antibodies, which recognize 5-HT2 receptors. [125I]-DOI binding was inhibited by guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S) and the antibodies were displaced by spiperone. Data are consistent with the hypothesis that 5-HT serves as a PF to F cell messenger.
    [Abstract] [Full Text] [Related] [New Search]