Pharmacological characterisation of [35S]-GTPgammaS binding to Chinese hamster ovary cell membranes stably expressing cloned human 5-HT1D receptor subtypes.
[35S]-GTPgammaS binding has been used to study the function of cloned human 5-HT1D receptor subtypes stably expressed in chinese hamster ovary (CHO) cells. 5-HT stimulated [35S]-GTPgammaS binding to membranes from cells expressing 5-HT1Dalpha or 5-HT1Dbeta receptors. In membranes containing 5-HT1Dbeta receptors, 5-CT and sumatriptan stimulated binding to a similar extent as 5-HT while yohimbine, metergoline and 8-OHDPAT were partial agonists. The order of potency for agonists was 5-CT > 5-HT > metergoline > sumatriptan > yohimbine > 8-OHDPAT. The stimulation of binding by 5-HT in membranes containing 5-HT1Dbeta receptors was potently antagonised by methiothepin (pA2 8.9 +/- 0.1). The overall pharmacological profile for the human 5-HT1Dbeta receptor, defined using [35S]-GTPgammaS binding, agreed well with that reported for inhibition of forskolin-stimulated adenylyl cyclase. In addition, methiothepin and ketanserin inhibited basal [35S]-GTPgammaS binding to membranes containing 5-HT1Dalpha or 5-HT1Dbeta receptors, suggesting that these compounds show negative efficacy at 5-HT1D receptor subtypes. The data show that [35S]-GTPgammaS binding is a suitable method for studying the interaction between cloned human 5-HT1D receptors and G-proteins.
Thomas
D R
DR
Department of Psychiatry Research, SmithKline Beecham Pharmaceuticals, Harlow, Essex, UK.
Faruq
S A
SA
Balcarek
J M
JM
Brown
A M
AM
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism*; D006801:Humans; D007650:Ketanserin / Q000494:pharmacology; D008711:Metergoline / Q000494:pharmacology; D008719:Methiothepin / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D018170:Sumatriptan / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D008711:Metergoline; D015016:Yohimbine; D012701:Serotonin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D008719:Methiothepin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D018170:Sumatriptan; C047087:5-carboxamidotryptamine; D007650:Ketanserin