Functional characterisation of a 5-HT2 receptor cDNA cloned from Lymnaea stagnalis.
A G-protein-coupled receptor (5-HT2Lym) resembling members of the 5-HT2 receptor subfamily was cloned from the mollusc Lymnaea stagnalis. Serotonin induces a concentration-dependent increase in intracellular inositol phospates in HEK293 cells expressing this receptor (EC50 = 114 nM). 5-HT2Lym differs from mammalian 5-HT2 receptors by the presence of a large amino-terminal region. This large domain appears to preclude an adequate level of expression of 5-HT2Lym in HEK293. Therefore, we constructed a cDNA encoding an amino-terminally truncated receptor (delta N-5-HT2Lym) that appeared to be much better expressed in HEK293 cells. delta N-5-HT2Lym-expressing cells exhibit a serotonin-induced stimulation of phosphatidylinositol bisphosphate hydrolysis (EC50 = 11.4 nM) and a high-affinity binding of the 5-HT2-selective antagonist [3H]mesulergine (Kd = 4 nM). Inhibition of this binding by several 5-HT2 antagonists and agonists revealed a pharmacological profile most closely resembling those of 5HT2Dro, 5-HT2B and 5-HT2C.
Department of Biochemistry and Molecular Biology, Vrije Universiteit, Amsterdam, Netherlands.
C C
CC
Gerhardt
J E
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Leysen
R J
RJ
Planta
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E
Vreugdenhil
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H
Van Heerikhuizen
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D008195:Lymnaea; D008969:Molecular Sequence Data; D008974:Mollusca; D011985:Receptors, Serotonin / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
D018076:DNA, Complementary; D011985:Receptors, Serotonin; C103526:serotonin 2Lym receptor, Lymnaea stagnalis; D019204:GTP-Binding Proteins