Alcohols and anesthetics enhance the function of 5-hydroxytryptamine3 receptors expressed in Xenopus laevis oocytes.
Alcohols and anesthetics enhance the function of 5-hydroxytryptamine3 receptors expressed in Xenopus laevis oocytes.
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发表时间：
1994-11
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通讯作者：
T. Machu;R. Harris
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作者：
T. Machu;R. Harris
5-羟色胺3（5-HT 3）受体的一个亚基已被克隆，编码该蛋白的cDNA在非洲爪蟾卵母细胞中的表达导致同源离子通道的形成。在本研究中，该系统被用来定义5-HT 3受体对酒精和麻醉剂的敏感性。乙醇，在适当的浓度，增强5-HT介导的电流，与最大的增强作用，观察到在较低浓度的5-HT。同样，丁醇刺激受体，但比乙醇具有更大的功效和效力。挥发性麻醉药异氟烷、氟烷和1，2，2-三氟环丁烷（F3）均增强5-HT 3受体功能。这些麻醉剂的浓度低于最低肺泡麻醉浓度（MAC）产生显着刺激5-HT介导的电流。与酒精类似，麻醉剂对5-HT 3受体功能的最大增强作用出现在较低浓度的5-HT。然而，麻醉剂在增强5-HT 3受体功能方面比乙醇有效得多。在0.5 μ M的5-HT的存在下，乙醇的最大刺激约为50%，但5-HT 3受体介导的电流的麻醉增强没有达到最大值。在测试的浓度范围内，麻醉剂使0.5 μ M 5-HT介导的电流增强约25%至400%。静脉麻醉剂丙泊酚没有增强5-HT 3受体功能或改变氟烷对该受体的增强作用。这些结果表明，酒精和挥发性麻醉剂对5-HT 3受体功能具有相似的作用，这与配体门控离子通道超家族其他成员的研究结果一致。（250字处删节）
One subunit of the 5-hydroxytryptamine3 (5-HT3) receptor has been cloned, and expression of cDNA coding for this protein in Xenopus oocytes results in the formation of homomeric ion channels. In the present study, this system was used to define the sensitivity of the 5-HT3 receptor to alcohols and anesthetics. Ethanol, in pharmacologically relevant concentrations, potentiated 5-HT-mediated currents, with the greatest potentiation observed at lower concentrations of 5-HT. Likewise, butanol stimulated the receptor but with greater efficacy and potency than ethanol. The volatile anesthetics isoflurane, halothane and 1,2,2-trifluorocyclobutane (F3) all enhanced 5-HT3 receptor function. Concentrations of these anesthetics below the minimal alveolar concentration for anesthesia (MAC) produced significant stimulation of 5-HT-mediated currents. Similar to the alcohols, the greatest enhancement of 5-HT3 receptor function by anesthetics was seen at lower concentrations of 5-HT. However, anesthetics were substantially more efficacious than ethanol in enhancing 5-HT3 receptor function. In the presence of 0.5 microM 5-HT, maximal stimulation by ethanol was approximately 50%, but anesthetic enhancement of 5-HT3 receptor-mediated currents did not reach a maximum. Over the concentrations tested, anesthetics potentiated 0.5 microM 5-HT-mediated currents by approximately 25% to 400%. The intravenous anesthetic propofol did not enhance 5-HT3 receptor function or change the potentiation of this receptor by halothane. These results suggest that alcohols and volatile anesthetics have similar actions on 5-HT3 receptor function, which is in agreement with results of studies with other members of the superfamily of ligandgated ion channels.(ABSTRACT TRUNCATED AT 250 WORDS)