Morales B, Madrid R, Bacigalupo J
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
FEBS Lett. 1997 Feb 3;402(2-3):259-64. doi: 10.1016/s0014-5793(97)00005-7.
In toad olfactory neurons, a putrid odorant mixture inducing inhibitory responses increases Ca2+-activated K+ conductance, developing a hyperpolarizing receptor potential. Removal of extracellular Ca2+ or exposure to nifedipine reversibly reduced the inhibitory response, suggesting that odorants induce a Ca2+ influx. We show evidence for an odorant-induced Ca2+ current. Using confocal microscopy, it is shown that odorants induce a nifedipine-sensitive elevation of Ca2+ in the apical end of the cell. These results suggest an inhibitory mechanism in which an apical Ca2+ influx causes an increase in internal Ca2+, opening Ca2+-activated K2+ channels that lead to membrane hyperpolarization.
在蟾蜍嗅觉神经元中，一种诱导抑制性反应的腐臭气味混合物会增加钙离子激活的钾离子电导，产生超极化受体电位。去除细胞外钙离子或暴露于硝苯地平会使抑制性反应可逆性降低，这表明气味剂会诱导钙离子内流。我们提供了气味剂诱导钙离子电流的证据。使用共聚焦显微镜显示，气味剂会在细胞顶端引起硝苯地平敏感的钙离子升高。这些结果提示了一种抑制机制，即顶端钙离子内流导致细胞内钙离子增加，从而打开钙离子激活的钾离子通道，导致膜超极化。
