The C and E subunits of the serotonin 5-HT3 receptor subtly modulate electrical properties of the receptor - 31/12/17
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Graphical abstract |
Highlights |
• | 5-HT induced larger current density in cells co-expressing 5-HT3AC subunits compared to 5-HT3A subunit alone. |
• | Tri-heteromeric 5-HT3ACE receptors produced whole-cell currents with larger maximum rise slope and baseline difference. |
• | Co-expression of C and/or E subunits with 5-HT3A receptors varied ondansetron inhibition of 5-HT-induced currents. |
• | Palonosetron rapidly and substantially inhibited 5-HT-induced currents on cells co-expressing 5-HT3ACE subunits. |
Abstract |
Serotonin type 3 (5-hydroxytrptamine-3, 5-HT3) receptors are ligand-gated cation channels present in both central and peripheral nervous systems. In humans there are five different subunits (A, B, C, D and E) of 5-HT3 receptors which can form homomeric or heteromeric receptors that may account for discrepancies in patient responses to treatments. The present study commences characterisation of the profiles of human 5-HT3 receptors containing C and/or E subunits. Recombinant 5-HT3 receptors were expressed transiently in HEK293T cells and expression was checked via immunocytochemistry staining against each epitope-tagged subunits. Functional characterisation of different combinations of 5-HT3 receptor complexes was studied via patch clamp whole cell recordings. In this study, increased current was seen in cells containing A and C subunits but only subtle changes were seen in the electrical properties of cells expressing A, AE, or ACE subunits in response to the ligand, 5-HT. Both di- and tri-heteromeric 5-HT3 receptors were significantly inhibited by the antagonists, ondansetron and palonosetron. Notably, palonosetron exerted stronger and more rapid inhibition on the 5-HT3 receptor ACE tri-heteromer compared to homomeric and di-heteromeric counterparts. This study demonstrated that the C and E subunits when assembled as simple or complex heteromeric 5-HT3 receptors may alter efficacies of 5-HT and clinically used antagonists such as ondansetron and palonosetron, and this in turn may have implications for patient responses to therapies.
Le texte complet de cet article est disponible en PDF.Keywords : HTR3C, HTR3E, Patch-clamp, Ligand-gated ion channel, Palonosetron, Ondansetron
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Vol 97
P. 1701-1709 - janvier 2018 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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