Characteristics of biphasic slow depolarizing and slow hyperpolarizing potential in frog taste cell induced by parasympathetic efferent stimulation.
Characteristics of biphasic slow depolarizing and slow hyperpolarizing potential in frog taste cell induced by parasympathetic efferent stimulation.
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DOI：
10.1093/chemse/bjm049
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发表时间：
2007-11
期刊：
影响因子：
3.5
通讯作者：
Toshihide Sato;K. Nishishita;Y. Okada;K. Toda
中科院分区：
文献类型：
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作者：
Toshihide Sato;K. Nishishita;Y. Okada;K. Toda
当蛙舌毛细血管血流速度下降到0.2- 0.7mm/s时，刺激舌咽神经可在味觉细胞中引起慢去极化和慢超极化双相电位（HP）。本工作的目的是研究双相慢电位的产生机制。双相慢反应之前总是由一个缓慢的去极化电位（DP）的组件，然后由一个缓慢的HP组件。静脉注射筒箭毒碱完全阻断了双相慢反应，这表明双相慢电位的两个组成部分都是由副交感神经（PSN）纤维引起的。味觉细胞的膜电导在慢DP期间增加，在慢HP期间减少。双相慢反应的任一成分的逆转电位几乎是相同的值，为-12 mV。神经递质P物质神经激肽（1）受体拮抗剂L-703，606完全阻断双相慢反应的两个成分。味细胞膜上的非选择性阳离子通道的拮抗剂氟灭酸完全阻断了双相慢反应。这些结果表明，PSN诱导的双相慢反应是通过在PSN轴突终末释放P物质而在味觉细胞中突触后引起的。它的结论是，慢DP组件可以通过打开一种类型的非选择性阳离子通道上的味细胞和慢HP组件可以通过关闭其他类型的非选择性阳离子通道产生。我们讨论了第二信使肌醇1，4，5-三磷酸可能与一个缓慢的DP组件和另一个第二信使甘油二酯可能与一个缓慢的HP组件。
When the velocity of capillary blood flow in the frog tongue declined to an intermediate range of 0.2-0.7 mm/s, the glossopharyngeal nerve stimulation induced a biphasic slow depolarizing and slow hyperpolarizing potential (HP) in taste cells. The objective of this work was to examine the generative mechanisms of the biphasic slow potentials. The biphasic slow response was always preceded by a slow depolarizing potential (DP) component and followed by a slow HP component. Intravenous injection of tubocurarine completely blocked the biphasic slow responses, suggesting that both components of the biphasic slow potentials are evoked by the parasympathetic nerve (PSN) fibers. Membrane conductance of taste cells increased during slow DPs and decreased during slow HPs. The reversal potential of either component of a biphasic slow response was the almost same value of -12 mV. An antagonist, L-703,606, for neurotransmitter substance P neurokinin(1) receptor completely blocked both components of the biphasic slow responses. An antagonist, flufenamic acid, for nonselective cation channels on the taste cell membrane completely blocked the biphasic slow responses. These results suggest that PSN-induced biphasic slow responses are postsynaptically elicited in taste cells by releasing substance P at the PSN axon terminals. It is concluded that the slow DP component may be generated by opening one type of nonselective cation channel on taste cells and that the slow HP component may be generated by closing the other type of nonselective cation channel. We discussed that a second messenger inositol 1,4,5-trisphosphate might be related to a slow DP component and another second messenger diacylglycerol might be related to a slow HP component.