Heatpipe System for Thermal Stimulation of Organims.

生物局部组织的加热和冷却是热生理研究的主要技术。特别是对作为检测体内温度的主要部位之一的大脑的热刺激，为体温调节的中心机制提供了许多重要的知识。目前，对大脑的热刺激主要是通过水灌注的热模来实现的。然而，这种方法需要持续的水供应，这不可避免地限制了动物的行为。此外，最薄的热模是直径0.8毫米。由于沿热模方向的热梯度是不可避免的，因此仅对小体积进行热刺激是困难的。也可以用激光束或高频电流刺激，但这种方法只能加热。在目前的研究中，我们试图开发一种小型的热模，特别是用于大脑的热刺激，使用“热管”。1990年，我们成功地制作了长25毫米、直径0.7毫米的银热管。从中子图证实，这确实是一个热管。在热管的一端，安装了一个用于加热和冷却的模块，该模块由一个小型Peltier装置（5 X 5 mm）和一个冷却鳍组成。整个系统的重量只有0.6克。1991年，我们将这种热模植入大鼠大脑并测试其容量。在大脑温度为-C^的情况下，珀耳帖器件电流为0.6 a时，温度可以改变1.3C^。热管热模可以用于局部冷却和加热有机组织。但需要研制一种圆形的珀尔帖装置，才能使该装置向热管有良好的热流，否则这种小热管无法用于冷却。

Heating and cooling of local tissue of organisms are a major technique for thermophysiological study. Especially, thermal stimulation of the brain, which is one of the major site for detecting internal body temperature, has provided many important knowledges concerning the central mechanisms of body temperature regulation. At present, thermal stimulation of the brain is made mostly with a waterperfused thermode. This method, however, requires continuous water supply that inevitably restricts animal's behavior. Additionally, the thinnest thermode available is that with 0.8 mm diameter. And because thermal gradient along thermode is inevitable, it is difficult to make thermal stimulation only to a small volume. Stimulation with laser beam or high frequency current is also used, but only warming is possible with the method. In the present study, we tried to develop a small thermode especially for thermal stimulation of the brain, using a "heatpipe". In 1990, we succeeded in making a silver heatpipe of 25 mm length with 0.7 mm diameter. It was confirmed from neutron picture that this certainly works as a heatpipe. At one end of the heatpipe a module for heating and cooling, which consist of a small Peltier device (5 X 5 mm) and a cooling fin, was attached. Whole system weighed only 0.6 g. In 1991, we implanted this thermode into rat brain and tested for its capacity. At a brain temperature of --C^ﾟ the temperature could be changed by 1.3C^ﾟ at a Peltier device current of 0.6 A. The heatpipe thermode might be able to use for local coolin and heating of the organic tissues. But it is required to develope a round shaped Peltier device for getting a good heat flow from the device to the heatpipe, otherwise this small heatpipe can not be used for cooling.