Oliet S H, Bourque C W
Centre for Research in Neuroscience, Montreal General Hospital, McGill University, Quebec, Canada.
Neuron. 1996 Jan;16(1):175-81. doi: 10.1016/s0896-6273(00)80034-3.
Stretch-sensitive ion channels are ubiquitous, yet evidence of their role in mechanotransduction remains scarce. The presence of stretch-inactivated cation channels in supraoptic neurons is consistent with the osmoreceptor potentials regulating vasopressin release. However, whether osmosensitivity depends on mechanical gating and ion flux through stretch-inactivated channels is unknown. Here we report that changes in channel open probability associated either with modification of pipette pressure or with external osmolality selectivity result from variations in closed time. While channel mechanosensitivity and osmotically evoked changes in cell volume are not affected by gadolinium, similar concentrations of the lanthanide inhibit cation permeation through the single channels and macroscopic osmoreceptor potentials. Mechanotransduction through stretch-inactivated channels is therefore necessary for osmoreception in supraoptic neurons.
拉伸敏感离子通道广泛存在，但其在机械转导中的作用证据仍然稀少。视上核神经元中存在拉伸失活阳离子通道，这与调节血管加压素释放的渗透压感受器电位一致。然而，渗透压敏感性是否取决于通过拉伸失活通道的机械门控和离子通量尚不清楚。在此我们报告，与移液管压力改变或外部渗透压选择性相关的通道开放概率变化是由关闭时间的变化引起的。虽然通道机械敏感性和细胞体积的渗透压诱发变化不受钆的影响，但相似浓度的镧系元素会抑制阳离子通过单通道的渗透以及宏观渗透压感受器电位。因此，通过拉伸失活通道的机械转导对视上核神经元的渗透压感受是必要的。
