Ohkuma M, Kawai F, Miyachi E
Department of Physiology, Fujita Health University, Toyoake, Aichi, Japan.
J Neural Transm (Vienna). 2002 Nov;109(11):1365-71. doi: 10.1007/s00702-002-0741-4.
Odorants are known to suppress voltage-gated channels not only in olfactory receptor cells but also in neurons of outside of the olfactory system. Here we found that odorants suppress glutamate-gated channels in newt retinal neurons using the Ca(2+) imaging technique. Bath application of 100 microM glutamate rose Ca(2+) under application of the voltage-gated Ca(2+) channel blocker. Thus, Ca(2+) rises in the neurons were most likely attributable to Ca(2+) influx via Ca(2+)-permeable glutamate-gated channels rather than voltage-gated Ca(2+) channels. A similar increase of Ca(2+) was observed by application of 100 microM NMDA and 50 microM kainate, suggesting that both NMDA and AMPA/kainate receptors were expressed in newt retinal neurons. Application of odorants, 1 mM amyl acetate and acetophenone, reversibly reduced Ca(2+) increased by glutamate, NMDA and kainate. This suggests that odorants can suppress not only voltage-gated channels but also ligand-gated channels such as NMDA and AMPA/kainate receptors.
已知气味剂不仅能抑制嗅觉受体细胞中的电压门控通道，还能抑制嗅觉系统外神经元中的电压门控通道。在这里，我们使用钙离子成像技术发现，气味剂能抑制蝾螈视网膜神经元中的谷氨酸门控通道。在电压门控钙通道阻滞剂存在的情况下，浴槽中加入100微摩尔谷氨酸会使细胞内钙离子浓度升高。因此，神经元中细胞内钙离子浓度升高很可能归因于通过钙离子通透的谷氨酸门控通道的钙离子内流，而非电压门控钙通道。通过加入100微摩尔NMDA和50微摩尔海人藻酸也观察到了类似的细胞内钙离子浓度升高，这表明蝾螈视网膜神经元中同时表达了NMDA和AMPA/海人藻酸受体。加入气味剂1毫摩尔乙酸戊酯和苯乙酮后，可使由谷氨酸、NMDA和海人藻酸引起的细胞内钙离子浓度升高出现可逆性降低。这表明气味剂不仅能抑制电压门控通道，还能抑制诸如NMDA和AMPA/海人藻酸受体等配体门控通道。
