A relationship of a salivary secretion-body fluid balance axis and drinking behavior.

尿液和汗液的量由体液稳态的控制系统调节。因为唾液是由血液产生的，所以唾液的体积就像尿液和汗液的体积一样，随着体液的渗透压和体积而变化。Olsson（1976）报告称，静脉注射高渗NaCl溶液可降低清醒山羊的分泌腺唾液流速。相反，注射高浓度葡萄糖或甘油溶液以相反的方式影响唾液分泌。另一方面，Yoshimura等人（1968）报告称，犬i.c.v.注射高渗NaCl溶液可增加吡罗卡品诱导的唾液分泌量。因此，关于高渗刺激对唾液分泌的中枢调节还没有达成共识，人们认为，侧脑室注射高渗溶液直接作用于室周和下丘脑区域的神经元。当细胞体积在高渗刺激期间收缩时，非选择性通道打开。如果唾液分泌中涉及类似的细胞机制，那么中枢给药后，任何高渗兴奋剂都可能以相同的方向影响唾液分泌。本研究旨在了解静脉注射高渗溶液对腮腺反射性唾液分泌的影响。为了这个目的，我们使用大鼠作为实验动物，因为它们的中枢神经系统调节是很好理解的。脑室内（i.c.v.）在清醒大鼠上观察了高渗氯化钠和蔗糖对腮腺反射性唾液分泌的影响。与生理盐水相比，两种高渗溶液均降低了进食固体饲料引起的唾液体积和流速。提示中枢渗透觉影响大鼠腮腺唾液分泌。

The volume of urine and sweat is regulated by a control system of the body fluid homeostasis. Because saliva is produced from blood, the volume of saliva, like that of urine and sweat, changes with the osmotic pressure and volume of body fluid. Olsson (1976) reported that i.c.v. injection of hypertonic NaCl solution reduced the parcctid salivary flow rate in conscious goats. By contrast, injection of hypertccnic glucose or glycerol solutions affected salivary secretion in the opposite way. On the other hand, Yoshimura et al. (1968) reported that the volume of salivary secretion induced by pirocarpine was increased by i.c.v. injection of hypertonic NaCl solution in dogs. Thus, there is no consensus of opinion about a central regulation of salivary secretion by hyperosmotic stimulation.It is believed that intracerebroventricularly injected hyperosmotic solutions exert their effects directly upon osmosensitive neurones in the circumventricular and hypothalamic regions. Nonselective channels are opened when cell volume shrinks during hyperosmotic stimulation. If a similar cellular mechanism is involved in salivary secretion, then any hypertonic stimulants, after central administration, may influence the salivary secretion in the same direction. The present study was designed to understand the effects of i.c.v. injection of hypertonic solutions on reflex parotid salivary secretion. For this purpose, we used rats as experimental animals because their central osmoregulation was well understood. The effects of intracerebroventricular (i.c.v.) injection of hypertonic NaCl and sucrose on reflex parotid salivary secretion were studied in conscious rats. Saliva volume and flow rate induced by eating solid diets were decreased by both the hypertonic solutions, compared with the normal saline. This suggests that central osmotic perception affects parotid salivary secretion in rats.