The escape response and rhythmic swimming in zebrafish are distinct behaviors mediated by two functionally distinct motoneuron (Mn) types. The primary (1°Mn) type depresses and has a large quantal content (Qc) and a high release probability (Pr). Conversely, the secondary (2°Mn) type facilitates and has low and variable Qc and Pr. This functional duality matches well the distinct associated behaviors, with the 1°Mn providing the strong, singular C bend initiating escape and the 2°Mn conferring weaker, rhythmic contractions. Contributing to these functional distinctions is our identification of P/Q-type calcium channels mediating transmitter release in 1°Mns and N-type channels in 2°Mns. Remarkably, despite these functional and behavioral distinctions, all ∼15 individual synapses on each muscle cell are shared by a 1°Mn bouton and at least one 2°Mn bouton. This blueprint of synaptic sharing provides an efficient way of controlling two different behaviors at the level of a single postsynaptic cell.

斑马鱼的逃避反应和有节奏的游泳是由两种功能不同的运动神经元（Mn）类型介导的不同行为。初生型（1°Mn）令人沮丧，其定量含量（Qc）大，释放概率高（Pr）。相反，次级（2°Mn）类型的Qc和Pr较低且可变。这种功能对偶很好地匹配了不同的相关行为，其中1°Mn提供了强烈的，奇异的C弯曲引发逃逸，而2°Mn提供了较弱的节律性收缩。有助于我们区分这些功能的是我们鉴定的P / Q型钙通道介导了1°Mns中的递质释放，而N型通道则介导了2°Mns中的递质释放。值得注意的是，尽管有这些功能和行为上的区别，每个肌肉细胞上的所有〜15个单独的突触都由1°Mn钮扣和至少一个2°Mn钮扣共享。突触共享的蓝图提供了在单个突触后细胞水平上控制两种不同行为的有效方法。