Analysis of neurosecretory activities by real-time image processing

通过实时图像处理分析神经分泌活动

基本信息

批准号：
62570047
负责人：
TERAKAWA Susumu
金额：
$ 1.22万
依托单位：
Okazaki National Research Institutes, National Institute for Physiological Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

In order to determine the origin of the light scattering change associated with the secretory activity in nervous tissues, transparency of these tissues was examined through a video camera attached to a high power microscope. The video signal was processed to produce contrast enhanced differential images. By virtue of this system accurate site of optical response could be visualized.In the sinus gland of the lobster, the site of the optical response was nerve terminals, and not smooth muscles, blood vessels or other contractile elements. The image could be reversibly suppressed by Cd-containing or Ca-deficient medium. The response could be greatly enhanced by tetraethylammonium and ouabain.Differential images of the rat neurohypophysis was obtained with a highest spatial resolution. They consisted of many small dots of 0.3 um in diameter inside nerve terminals, suggesting that individual secretory granules inside the nerve terminals are the site of optical response. The amplitude of scattering response increased with the frequency of stimulation. Therefore, the scattering response share the same property as that of peptide release from this tissue. Furthermore, the amplitude had a linear relationship with amount of vasopressin measured by radioimmunoassay in the same preparation simultaneously. From these findings, scattering response can be most directly ascribed to the exocytosis of individual secretory granules.This mechanism was further confirmed in an isolated single chromaffin cell which showed a clear image of exocytosis directly under video enhanced bright-field microscope. The exocytosis appeared as an increase in light intensity on very localized spot on the plasma membrane. The time course of the light intensity in active part of a single cell showed a change very similar to scattering change observed by a photodiode.The present study established that the scattering response of the secretory cell is a direct measure of exocytotic activities.

为了确定与神经组织分泌活动相关的光散射变化的起源，通过连接到高倍显微镜的摄像机检查了这些组织的透明度。视频信号经过处理以产生对比度增强的差分图像。借助该系统，可以直观地看到光学反应的准确位置。在龙虾的窦腺中，光学反应的位置是神经末梢，而不是平滑肌、血管或其他收缩元件。图像可以被含镉或缺钙介质可逆地抑制。四乙铵和哇巴因可以大大增强该反应。以最高的空间分辨率获得了大鼠神经垂体的差异图像。它们由神经末梢内许多直径0.3微米的小点组成，表明神经末梢内的单个分泌颗粒是光学反应的部位。散射反应的幅度随着刺激频率的增加而增加。因此，散射响应与从该组织释放的肽具有相同的特性。此外，该振幅与同时在同一制剂中通过放射免疫测定法测得的加压素的量呈线性关系。从这些发现来看，散射反应可以最直接地归因于单个分泌颗粒的胞吐作用。这种机制在分离的单个嗜铬细胞中得到进一步证实，该细胞在视频增强明视野显微镜下直接显示出清晰的胞吐作用图像。胞吐作用表现为质膜上非常局部的点上光强度的增加。单个细胞活性部分的光强度的时间过程显示出与光电二极管观察到的散射变化非常相似的变化。本研究确定分泌细胞的散射响应是胞吐活动的直接测量。