Laser trapping of menbrane protein particles in neurons

神经元在发育过程中以及损伤后轴突萌发过程中突出生长锥。利用全细胞膜片钳记录靠近生长锥的富含乙酰胆碱受体的神经元作为ACh释放传感器，监测培养中央胆碱能神经元生长锥诱导释放乙酰胆碱（ACh）。生长锥的同步视频增强DIC成像显示ACh释放后生长锥与感觉神经元之间的接触。当生长球果暴露在高钾溶液中时，还观察到生长球果与乳胶珠之间的粘附。珠粒附着在生长锥膜上后，需要1 pN的激光光压力才能使珠粒在生长锥表面移动约0z1至1mum。通过分析激光捕获微珠的视频图像，估计了生长锥膜表面粘度的变化。

Neurons protrude growth cones during development and also during axon sprouting after damage. Evoked release of acetylcholine (ACh) from the growth cones of central cholinergic neurons in culture was monitored using whole-cell patch clamp recording from ACh-receptor-rich neuron placed close to the growth cones as a sensor of ACh release. Simultaneous video-enhanced DIC imaging of growth cones showed contacts between growth cones and the sensor neuron after ACh release. Adhesion was also observed between growth cones and latex beads, when growth cones were exposed to high potassium solution. After beads attached on the growth cone membrane, 1 pN of laser optical pressure was required for moving the beads about 0z1 to 1 mum on the growth cone surface. The changes in the surface viscosity of the growth cone membrane was estimated by analyzing the video images of laser trapped beads on it.