A calcium-receptor agonist induces gustatory neural responses in bullfrogs
A calcium-receptor agonist induces gustatory neural responses in bullfrogs
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DOI：
10.1007/s10571-007-9171-z
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发表时间：
2007-09-01
影响因子：
4
通讯作者：
Toda, Kazuo
中科院分区：
文献类型：
--
作者：
Okada, Yukio;Imendra, Kotapola G.;Toda, Kazuo
采用舌咽神经记录和离体味觉盘细胞全细胞膜片钳记录技术研究了钙敏感受体（CaR）激动剂对蛙味觉反应的影响。将拟钙剂BXR-467溶于生理盐水溶液中，在神经中引起大的瞬时反应。该化合物的活性较低的对映异构体，C14 S-467仅诱导小的神经反应。EC 50为约20 μ M。进行交叉适应实验，以检查30 μ M的miR-467和100 μ M的奎宁对味觉神经反应的影响。适应奎宁后R-467诱导的反应的幅度近似等于适应生理盐水溶液后的反应，表明RXR-467的受体位点不同于奎宁的位点。在15个视杆细胞中，有2个（13%）的视杆细胞出现内向电流，同时电导增加，去极化幅度较大;在6个（40%）的视杆细胞中，外向电流持续下降，去极化幅度较小。ALS-467（100 μ M）诱导持续减少外向电流和去极化在5（50%）的10个视杆细胞。另一个钙模拟西那卡塞（100 μ M）诱导的内向电流伴随着电导增加的11个视杆细胞中的三个（27%）。这些结果表明，ARXR-467通过与静息K+电导降低无关的细胞反应诱导神经反应。
The effect of calcium-sensing receptor (CaR) agonists on frog gustatory responses was studied using glossopharyngeal nerve recording and whole-cell patch-clamp recording of isolated taste disc cells. Calcimimetic NPS R-467 dissolved in normal saline solution elicited a large transient response in the nerve. The less active enantiomer of the compound, NPS S-467 induced only a small neural response. The EC50 for NPS R-467 was about 20 mu M. Cross-adaptation experiments were performed to examine the effect of 30 mu M NPS R-467 and 100 mu M quinine on the gustatory neural response. The magnitude of the R-467-induced response after adaptation to quinine was approximately equal to that after adaptation to normal saline solution, indicating that the receptor site for NPS R-467 is different from the site for quinine. NPS R-467 (100 mu M) also induced an inward current accompanied with conductance increase and large depolarization in two (13%) of 15 rod cells, and a sustained decrease in outward current and small depolarization in six (40%) other rod cells. NPS S-467 (100 mu M) induced a sustained decrease in outward current and depolarization in five (50%) of 10 rod cells. Another calcimimetic cinacalcet (100 mu M) induced an inward current accompanied with conductance increase in three (27%) of 11 rod cells. The results suggest that NPS R-467 induces neural responses through cell responses unrelated to a resting K+ conductance decrease.