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Characterization of an Adenylate Cyclase‐Linked Serotonin (5‐HT 1 ) Receptor in a Neuroblastoma × Brain Explant Hybrid Cell Line (NCB‐20)

1983; Wiley; Volume: 40; Issue: 4 Linguagem: Inglês

10.1111/j.1471-4159.1983.tb08081.x

1471-4159

Elizabeth Berry‐Kravis, Glyn Dawson,

Ion channel regulation and function

Abstract: Clonal cell line NCB‐20 (a hybrid of mouse neuroblastoma N18TG2 and Chinese hamster 18‐day embryonic brain expiant) expressed both high‐ ( K D 180 n M ) and low‐affinity (>3000 n M ) binding sites for [ 3 H]serotonin (5‐HT) which were absent from the parent neuroblastoma. The low‐affinity binding site was eliminated by 1 μ M spiperone. The order of drug potency for inhibition of high‐affinity [ 3 H]5‐HT binding was consistent with a 5‐HT 1 receptor (5,6 ‐ dihydroxytryptamine = 5‐HT = methysergide = 5‐methoxytryptamine > cyproheptadine = clozapine = mianserin > spiperone > dopamine = morphine = ketanserin = norepinephrine). [ 3 H]5‐HT binding was inhibited by guanine nucleotides (e.g., GTP and Gpp(NH)p), whereas antagonist binding was not; as‐corbate was also inhibitory. A 30‐min exposure of cells to 1—2 μ M 5‐HT or other agonists produced a three‐ to fivefold stimulation of cyclic AMP levels. The order of potency for 5‐HT agonist stimulation of basal cyclic AMP levels and 5‐HT antagonist reversal of agonist‐stimulated levels was the same as the order of drug potency for inhibition of high‐affinity [ 3 H]5‐HT binding, suggesting linkage of the 5‐HT 1 receptor to adenylate cyclase in NCB‐20 cells.