The one that's on the top here is called ligand-gated ion channel and an ion channel is a protein that sits in the surface of a cell.

最上面的这个叫作配体门控离子通道,离子通道是一类位于细胞表面的蛋白

耶鲁公开课 - 生物医学工程探索课程节选

In some cases it might be a ligand-gated ion channel.

有时受体可能是一个配体门控离子通道

耶鲁公开课 - 生物医学工程探索课程节选