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. 2016 May 17;12(5):e1005651. doi: 10.1371/journal.ppat.1005651

Fig 6. Long lasting inhibition of Sm.5HT7R evoked by a subset of ligands.

Fig 6

Sm.5HTR displays an inactivating antagonist property reported for human 5HT7R. (A) Both the ‘inactivating antagonist’ bromocriptine (10μM, blue) and the competitive antagonist cyproheptadine (10μM, grey) acutely inhibit the effect of 5-HT (10μM) at Sm.5HTR (5-HT alone, black). (B) Sm.5HTR remains insensitive to 5-HT following washout of bromocriptine but not cyproheptadine. Cells were pre-incubated with antagonists as in (A) for 30 mins, followed by solution exchange, and the assay for 5-HT responsiveness 1hr later. (C) Inhibition of 5-HT response at Sm.5HTR by both ‘inactivating antagonists’ established at Hs.5HT7R (methiothepin, bromocriptine, lisuride, risperidone, metergoline) and competitive antagonists (clozapine, cyproheptadine). All drugs were tested at 10μM for 30mins. **, p <0.01. (D) Persistent effects of antagonists (10μM) shown in (C) after washout and subsequent assay for 5-HT response (1hr later). **, p <0.01, *, p <0.05. (E) Titration of these ‘inactivating antagonists’ revealed the dose-response relationship for Sm.5HTR inhibition after washout. Colors correspond to drug identity in C&D. Data represent mean±s.e.m., n = 3 (C-E).