Modney B K, Sahley C L, Muller K J
Department of Biology, Cleveland State University, Cleveland, Ohio 44115, USA.
J Neurosci. 1997 Aug 15;17(16):6478-82. doi: 10.1523/JNEUROSCI.17-16-06478.1997.
Sensitization is a form of nonassociative learning in which a strong or noxious stimulus persistently enhances the response produced by a weaker stimulus. In the leech Hirudo medicinalis, the S-interneuron is required for sensitization of the shortening response. A single S-cell axon was surgically separated from its sole synaptic partner, the neighboring S-cell. This consistently eliminated sensitization without impairing reflexive shortening itself, as measured in semi-intact specimens. Sensitization of the shortening reflex returned after 3 weeks when the severed axon grew and regenerated its specific electrical synapse within the nerve cord, as shown by restored conduction of impulses between S-cells. This confirms the essential role of one neuron, the S-cell, in sensitization, and it demonstrates that regeneration of the synapse between S-cells restores this example of nonassociative learning.
敏感化是一种非联合型学习形式，其中强烈或有害刺激会持续增强较弱刺激所产生的反应。在医用水蛭中，S中间神经元是缩短反应敏感化所必需的。单个S细胞轴突通过手术与其唯一的突触伙伴——相邻的S细胞分离。如在半完整标本中所测量的那样，这始终消除了敏感化，而不会损害反射性缩短本身。当切断的轴突生长并在神经索内重新形成其特定的电突触后，缩短反射的敏感化在3周后恢复，这可通过S细胞之间恢复的冲动传导来表明。这证实了一个神经元——S细胞在敏感化中的重要作用，并且表明S细胞之间突触的再生恢复了这种非联合型学习的实例。
