Vandorpe D H, Morris C E
Department of Biology, University of Ottawa, Ontario, Canada.
J Membr Biol. 1992 May;127(3):205-14. doi: 10.1007/BF00231508.
The S-channel, a receptor-mediated K+ channel of Aplysia sensory neurons which functions in neuromodulation, bears a strong resemblance to the ubiquitous stretch-activated channels of snail neurons. Snail neuron stretch channels are stretch sensitive only in the patch, not at the macroscopic level, a situation which leaves open the question of their physiological role. If S-channels resemble snail stretch channels because both belong to the same general class of channels, the S-channel, too, should display stretch sensitivity in the patch. We show, using single-channel recording, that the S-channel can be activated by stretch. Furthermore, we show that Aplysia neurons in general have stretch-activated K+ channels. We suggest that the stretch-sensitive K+ channels of molluscan neurons and other preparations (e.g., Drosophila muscle, snail heart) are S-like channels, i.e., receptor-mediated channels which adventitiously exhibit mechanosensitivity in the patch.
S通道是海兔感觉神经元中一种受体介导的钾通道，在神经调节中发挥作用，与蜗牛神经元中普遍存在的牵张激活通道极为相似。蜗牛神经元的牵张通道仅在膜片水平上对牵张敏感，而在宏观水平上则不然，这种情况使得它们的生理作用问题悬而未决。如果S通道与蜗牛牵张通道相似是因为它们都属于同一类通道，那么S通道在膜片中也应该表现出牵张敏感性。我们通过单通道记录表明，S通道可被牵张激活。此外，我们还表明，一般来说海兔神经元具有牵张激活的钾通道。我们认为，软体动物神经元和其他标本（如果蝇肌肉、蜗牛心脏）中的牵张敏感钾通道是类似S的通道，即受体介导的通道，它们在膜片中偶然表现出机械敏感性。
