Davenport R W, Dou P, Rehder V, Kater S B
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins 80523.
Nature. 1993 Feb 25;361(6414):721-4. doi: 10.1038/361721a0.
The dynamic nature of neuronal growth cone filopodia led to the suggestion that the primary function of filopodia is to sample their immediate environment, responding to and transducing environmental signals that affect growth cone behaviour and shape. Filopodia seem well suited to serve as antenna-like sensors, their broad span allows sampling of information over a greatly enhanced radius, and forward-projecting filopodia encounter potential cues in the molecular terrain long before the advancing growth cone itself. Filopodia in culture can serve structural roles, exert mechanical tension and selectively adhere to their surrounding. Whether or not filopodia have a general sensory role has not been tested directly, largely because of their small size, which limits an electrophysiological approach, and their integral relationship with the parent growth cone, which prevents resolution of their different functions. Here we use surgical procedures to isolate individual filopodia from their parent growth cone and, by monitoring their morphology and calcium second messenger systems, we show that neuronal growth cone filopodia contain signal transduction mechanisms that allow autonomous responses and the transmission of distant environmental information to their parent growth cone.
神经元生长锥丝状伪足的动态特性表明，丝状伪足的主要功能是对其周围环境进行采样，响应并转导影响生长锥行为和形态的环境信号。丝状伪足似乎非常适合作为类似天线的传感器，其广泛的跨度允许在大大增加的半径范围内采样信息，并且向前突出的丝状伪足在前进的生长锥本身之前很久就在分子环境中遇到潜在的线索。培养中的丝状伪足可以起到结构作用，施加机械张力并选择性地附着于周围环境。丝状伪足是否具有一般的感觉作用尚未得到直接测试，这主要是因为它们体积小，限制了电生理方法的应用，以及它们与母生长锥的整体关系，这妨碍了对其不同功能的分辨。在这里，我们使用手术程序将单个丝状伪足与其母生长锥分离，并通过监测它们的形态和钙第二信使系统，我们表明神经元生长锥丝状伪足包含信号转导机制，允许自主反应并将远处的环境信息传递给它们的母生长锥。
