Serotonergic agonists inhibit calcium-activated potassium and voltage-dependent sodium currents in rat taste receptor cells
Serotonergic agonists inhibit calcium-activated potassium and voltage-dependent sodium currents in rat taste receptor cells
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DOI：
10.1007/s002320001014
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发表时间：
2000-01-15
影响因子：
2.4
通讯作者：
Chen, Y
中科院分区：
文献类型：
--
作者：
Herness, MS;Chen, Y
最近我们报道了大鼠味觉受体细胞对神经递质5 -羟色胺的反应，抑制钙激活钾电流[17]。在本研究中，通过在全细胞结构中使用膜片钳记录技术研究一系列血清素能激动剂对味觉受体细胞膜特性、钙激活钾电流和电压依赖性钠电流的影响，证实并扩展了这一观察结果。激动剂N-（3-三氟甲基苯基）哌嗪和(+/-)-2-二丙胺-8-羟基-1,2,3,4-四氢萘模拟了5 -羟色胺对钙活化钾电流的抑制作用。两者都产生可逆的K-Ca抑制，并显著增加细胞的输入电阻。激动剂1-（1-萘基）哌嗪和丁螺环酮（两种5 -羟色胺受体1A激动剂）在降低K-Ca方面同样有效。向外电流不受苯基双胍（一种5 -羟色胺受体3激动剂）的影响，但电流受随后应用(+)-2-二丙基-s-羟基- 1,2,3,4-四氢萘的影响。两种激动剂n -（3-三氟甲基苯基）哌嗪和(+/-)-2-二丙胺-8-羟基1,2,3,4-四氢萘也在电压依赖性钠电流下进行了测试；在各种应用电位下，两者在减小其大小方面都是有效的和可逆的。这些数据与5 -羟色胺在大鼠味觉受体细胞中的作用是由5 -羟色胺1A受体介导的观点一致，尽管其他受体亚型可能会额外表达。5 -羟色胺可能影响味觉细胞的电特性在积极刺激在旁分泌的方式。
Recently we reported that rat taste receptor cells respond to the neurotransmitter serotonin with an inhibition of a calcium-activated potassium current [17]. In the present study, this observation is confirmed and extended by studying the effects of an array of serotonergic agonists on membrane properties, calcium-activated potassium current, and voltage-dependent sodium current in taste receptor cells using the patch-clamp recording technique in the whole-cell configuration. Serotonergic inhibition of calcium-activated potassium current was mimicked by the agonists N-(3-trifluoromethylphenyl)piperazine and by (+/-)-2-dipropylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene. Both produced reversible inhibition of K-Ca as well as significantly increasing the input resistance of the cell. The agonists 1-(1-naphthyl)piperazine and buspirone (both serotonin receptor 1A agonists) were similarly effective in reducing K-Ca. Outward current was unaffected by application of phenylbiguanide, a serotonin receptor 3 agonist, though current was affected by subsequent application of (+)-2-dipropylamjmo-s-hydroxy- 1,2,3,4-tetrahydronaphthalene. Two_ agonists-N-(3-trifluoromethylphenyl)piperazine and (+/-)-2-dipropylamino-8-hydroxy1,2,3,4-tetrahydronaphthalene-were also tested on voltage-dependent sodium currents; both were effective and reversible in reducing its magnitude at a variety of applied potentials.These data are consistent with the notion that serotonin effects in rat taste receptor cells are mediated by serotonin 1A receptors, though other receptor subtypes may be additionally expressed. Serotonin may affect the taste cell electrical properties during active stimulation in a paracrine fashion.