5-HT_1B and 5-HT₂ serotonin binding sites in cultured Wistar-Kyoto rat aortic smooth muscle cells

We studied [³H]serotonin ([³H]5-HT) binding on cultured arterial smooth muscle cells from rat aorta. We found a high and low affinity binding site. Binding to the higher affinity site could be displaced by drugs in an order corresponding most closely with the 5-HT_1B subtype, and high affinity [¹²⁵I]iodo-cyanopindolol binding was also found. We found evidence for a 5-HT₂ subtype using [³H]ketanserin binding, with similar results whether specific binding was determined using unlabelled ketanserin, methysergide or mianserin.