THERMAL DEHYDRATION-INDUCED THIRST

人类的热脱水与 工作能力，是导致中暑的主要因素。 热脱水引起的口渴对于预防 这些热脱水的有害影响。 客观 这项研究的目的是确定 在热刺激后， 脱水使用大鼠作为模型系统。 的具体目标 研究的目的是：（1）确定 水的摄入量和热脱水的程度， 确定B）渗透压增加，c）血容量减少， 和d）热脱水诱导的体温升高 口渴以及e）肾素血管紧张素系统的作用，f） 肾上腺素能系统，g）胆碱能系统和h）阿片类药物 口渴的类型 将使用雄性大鼠作为实验动物 在这些研究中。 将大鼠暴露于热环境（30-45 摄氏度），无水加热5小时， 脱水 从高温中取出后的水摄入量将 与体温和测量相关 脱水程度，如体重变化，血细胞比容， 血浆蛋白和钠浓度、血浆渗透压和 血浆肾素活性 选择性置换血浆容量 给予生理盐水或将渗透压恢复至正常， 将使用水输注来确定低血容量的作用 和增加的渗透压在热脱水引起的口渴。 结肠和皮肤温度的实验操作将 用于研究体温在这类疾病中的作用 口渴 中枢和外周药物阻断 肾上腺素能、胆碱能和阿片样物质的肾素-血管紧张素系统 受体将被用来研究这些系统的作用， 热脱水引起的口渴这些研究的信息 对我们理解热有着直接的重要性 应有助于设计干预措施， 热脱水及其健康后果。

Thermal dehydration in humans is associated with a decrease in work capacity and is a major contributing factor to heat stroke. Thirst induced by thermal dehydration is important in preventing these detrimental effects of thermal dehydration. The objective of the proposed research is to determine the physiological pathways involved in the thirst observed following thermal dehydration using rats as a model system. Specific aims of the proposed research are to a) determine the relationship between water intake and the degree of thermal dehydration and to determine the roles of b) increased osmolality, c) hypovolemia, and d) increased body temperature in thermal dehydration-induced thirst as well as the roles of the e) reninangiotensin system, f) adrenergic system, g) cholinergic system and h) opiates in this type of thirst. Male rats will be used as the experimental animal in these studies. Rats will be exposed to a hot environment (30-45 degree C) without water for up to 5 hours to induce thermal dehydration. Water intake following removal from the heat will be correlated with body temperatures and measurements of the degree of dehydration such as body weight changes, hematocrit, plasma protein and sodium concentrations, plasma osmolality and plasma renin activity. Selective replacement of plasma volume with saline administration or returning osmolality to normal with water infusion will be used to determine the roles of hypovolemia and increased osmolality in thermal dehydration-induced thirst. Experimental manipulations of colonic and skin temperature will be used to study the role of body temperatures in this type of thirst. Central and peripheral pharmacologic blockade of the reninangiotensin system, adrenergic, cholinergic and opiate receptors will be used to study the roles of these systems in thermal dehydration-induced thirst Information from these studies will be of direct importance in aiding our understanding of heat- induced thirst and should aid in designing interventions to prevent thermal dehydration and its health consequences.