当前位置： SCI文献检索 > EUROPEAN JOURNAL OF PHARMACOLOGY期刊下所有文献 > Characterization of the 5-HT6 receptor coupled to Ca2+ signaling using an enabling chimeric G-protein.

Characterization of the 5-HT6 receptor coupled to Ca2+ signaling using an enabling chimeric G-protein.

Abstract：

:We examined the feasibility of coupling the 5-HT(6) receptor to a Ca(2+) signaling read-out using a chimeric G-protein, comprising of G(alphaq) with the C-terminal five amino acids from G(alphas), to facilitate assays on the fluorometric imaging plate reader (FLIPR). Using a transient transfection assay in human embryonic kidney (HEK) cells, Ca(2+) signaling in response to serotonin (5-HT) was facilitated by co-transfection of the 5-HT(6) receptor with the G(alphaq)/G(alphas) chimera, but not with the 5-HT(6) receptor alone or with a similar chimera incorporating the C-terminal five amino acids of G(alphai3). A series of agonist concentration-response curves were constructed using the 5-HT(6)-G(alphaq)/G(alphas) signaling assay generating the following rank order of agonist potency; 5-methoxytryptamine (EC(50), 9 nM)=5-HT (12 nM)=2-methyl 5-HT (13 nM)>tryptamine (86 nM)=5-carboxamidotryptamine (5-CT) (119 nM)>lisuride (>1 microM). In comparison, essentially identical EC(50) values were observed for the stimulation of cAMP accumulation with the same compounds; 5-methoxytryptamine (EC(50), 6 nM)=5-HT (6 nM)=2-methyl 5-HT (15 nM)>tryptamine (91 nM)=5-CT (153 nM)>lisuride (>350 nM). Clozapine and SB 271046 both produced a concentration-dependent antagonism of the 5-HT-stimulated Ca(2+) response with IC(50) values of 45 and 11 nM, respectively. In contrast, aripiprazole, a recently launched atypical anti-psychotic with a novel mechanism of action described as a dopamine/serotonin stabilizer, was essentially devoid of 5-HT(6) receptor antagonist activity. Our results demonstrate that a FLIPR-based Ca(2+) signaling assay is a feasible approach to the functional characterization of 5-HT(6) receptor ligands. Moreover, the equivalent coupling efficiency, as indexed by agonist potency, observed using this system compared with the native coupling assay to cAMP suggests that the C-terminal five amino acids of G(alphas) are the major determinant for the receptor/G-protein interaction of the 5-HT(6) receptor subtype.

journal_name

Eur J Pharmacol

journal_title

European journal of pharmacology

authors

Zhang JY,Nawoschik S,Kowal D,Smith D,Spangler T,Ochalski R,Schechter L,Dunlop J

doi

10.1016/s0014-2999(03)01855-7

keywords:

subject

Has Abstract

pub_date

2003-07-04 00:00:00

pages

33-8

issue

1-2

eissn

0014-2999

issn

1879-0712

pii

S0014299903018557

journal_volume

472

pub_type

杂志文章

在线工具

Characterization of the 5-HT6 receptor coupled to Ca2+ signaling using an enabling chimeric G-protein.