Kim M, Mistretta C M
Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor 48109.
Brain Res. 1993 May 28;612(1-2):96-103. doi: 10.1016/0006-8993(93)91648-c.
To study the potential role of potassium channels in the taste response to potassium salts, we applied 4-aminopyridine (4-AP) to the anterior rat tongue and recorded chorda tympani nerve taste responses to chemical stimuli. 4-aminopyridine is a pharmacological blocker that reduces potassium conductance through potassium channels in nerve and muscle. Summated neural responses to stimuli dissolved in water and in 4-AP were compared. Chemical stimuli included concentration ranges of KCl, KBr, KH2PO4, CsCl, RbCl, NH4Cl, NaCl and sucrose. The blocker reduced chorda tympani responses to KCl and other potassium salts, from 0.025 to 0.25 M. Responses to ammonium, rubidium and cesium salts also were reduced, in order of effectiveness that would be predicted from known ion selectivity properties of potassium channels. Responses to NaCl and sucrose were not reduced. Other channel blockers, including tetraethylammonium chloride (TEA), BaCl2 and quinidine, did not reduce the response to KCl. These are the first detailed reports of effects of potassium channel blockers on the peripheral, neural taste response. The results are consistent with a role for potassium channels in apical taste bud cell membranes in transduction for potassium salts.
为研究钾通道在对钾盐的味觉反应中的潜在作用，我们将4-氨基吡啶（4-AP）应用于大鼠舌前部，并记录鼓索神经对化学刺激的味觉反应。4-氨基吡啶是一种药理阻断剂，可降低神经和肌肉中通过钾通道的钾电导。比较了对溶解于水和4-AP中的刺激的总和神经反应。化学刺激包括氯化钾、溴化钾、磷酸二氢钾、氯化铯、氯化铷、氯化铵、氯化钠和蔗糖的浓度范围。该阻断剂降低了鼓索神经对0.025至0.25M的氯化钾和其他钾盐的反应。对铵盐、铷盐和铯盐的反应也降低了，其有效性顺序与根据钾通道已知的离子选择性特性所预测的一致。对氯化钠和蔗糖的反应未降低。其他通道阻断剂，包括氯化四乙铵（TEA）、氯化钡和奎尼丁，并未降低对氯化钾的反应。这些是关于钾通道阻断剂对外周神经味觉反应影响的首批详细报告。结果与钾通道在顶端味蕾细胞膜中参与钾盐转导的作用一致。
