Abstract
The activation of 5-HT3 receptors by dopamine was studied in Xenopus oocytes voltage clamped at −70 mV. 5-HT3 receptors were expressed by the microinjection of cRNA transcripts from the cloned 5-HT3 receptor (Science, 254:432, 1991) and allowing 1 to 3 days for expression. The application of either the selective 5-HT3 agonist, 2-methyl-5-HT (100 μM), or dopamine (100 μM) did not induce a current in 12 uninjected oocytes from 3 different frogs. On the other hand, the application of 2-methyl-5-HT or dopamine induced a rapidly activating current in 10 cRNA injected oocytes from 3 different frogs. Currents activated by both agonists had the same reversal potential of −10 mV, and both currents were reversibly inhibited by the application of the selective 5-HT3 antagonist LY-278584 (1 μM). At a concentration of 100 μM, the selective D1 and D2 agonists, SKF-38393 and PPHT, respectively, failed to induce a current in 12 oocytes tested. The selective D1 and D2 antagonists, SCH-23390 and spiperone, respectively, up to a concentration of 10 μM, failed to inhibit the currents activated by 2-methyl-5-HT and dopamine. The results suggest that dopamine directly activates 5-HT3 receptors expressed in Xenopus oocytes.
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Oz, M., Zhang, L. & Weight, F. Dopamine Directly Activates 5-HT3 Receptors Expressed in Xenopus Oocytes. Neuropsychopharmacol 11, 279 (1994). https://doi.org/10.1038/sj.npp.1380191
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DOI: https://doi.org/10.1038/sj.npp.1380191