They discovered that, unlike in adult muscle, very early in development the muscle cells actually make multiple types of receptors, not just acetylcholine receptors.

• 不像成年人肌肉，这个发现是肌肉细胞在发育的非常早期阶段实际上产生多种类型的受体，而不仅仅是乙酰胆碱受体。