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: Modulation of 5-HT(1A) receptor-mediated Ca(2+) responses by co-expression with various recombinant G(alpha) proteins in CHO-K1 cells.
    Author: Wurch T, Pauwels PJ.
    Journal: Naunyn Schmiedebergs Arch Pharmacol; 2003 Aug; 368(2):99-105. PubMed ID: 12879209.
    Abstract:
    The ability of the human 5-HT(1A) receptor to activate different recombinant G(alpha) proteins was investigated in CHO-K1 cells by monitoring 5-HT ligand-mediated Ca(2+) responses upon co-expression with either G(alphaq), G(alpha15) or chimeric G(alphaq/i3) proteins. Each G(alpha) protein yielded a typical 5-HT-dependent Ca(2+) response with different kinetic parameters both for the onset-time of maximal Ca(2+) response (21 to 30 s) and time-dependent attenuation (43 to 73% of residual activity at 1 min upon peak Ca(2+) response). Pertussis toxin-treatment fully abolished the Ca(2+) responses mediated by both the endogenous G(i/o) and the chimeric-PTX-sensitive G(alphaq/i3) proteins. In contrast, Ca(2+) responses driven by recombinant G(alphaq) and G(alpha15) proteins were decreased by PTX, respectively by 52% and 35%, corresponding to the level of endogenous G protein activation. The pharmacology of the 5-HT ligand-mediated Ca(2+) responses was highly affected by both the presence and nature of the co-expressed G(alpha) protein. This influence was more pronounced for the partial agonists L 694247, 8-OH-DPAT, flesinoxan and buspirone in contrast to ipsapirone. The G(alpha) protein rank order for apparent increase of ligands' intrinsic activity was: G(alphaq) <G(alphaq/i3) <G(alpha15) protein. Each of the 5-HT-mediated Ca(2+) responses could be antagonised by WAY 100635, buspirone and methiothepin regardless of the absence or presence of a G(alphaq), G(alphaq/i3) or G(alpha15) protein. In conclusion, these data reinforce that depending on the presence and nature of the G(alpha) protein environment, 5-HT(1A) ligands may display a large spectrum of activities.
    [Abstract] [Full Text] [Related] [New Search]