HEAT EXPOSURE, DEHYDRATION AND FEVER

适当和协调的生理调整不断发生， 维持身体的稳态 这些活动涉及多个 监管系统，相互作用，以保持其最佳功能。 而 虽然在概念上理解得很好，但事实上，很少有研究探讨 系统地分析了不同监管体系之间的相互关系 当两种或两种以上的生理冲动同时发生时。 为 对不同驱力的反应通常利用相同的效应器通路， 当这些驱动器结合在一起时， 对身体施加并发的压力负荷，从而竞争 同样的机制在同一时间。 这就提出了一个问题： 当竞争性的需求被放在 共享机制？ 一个特殊的困境发生在身体方面 温度控制，因为温度调节系统不具有 它自己的效应器，而是取决于其他系统的效应器，例如， 循环系统、呼吸系统等，这也可能需要在 同时防御其他变量。 的情况的示例 这种冲突可能出现的原因是， 感染是一起发生的。 此外，这些压力因素在一定程度上要求 通过共同的效应器机制产生相反的反应。 未能充分 满足需求可能导致代偿失调，例如，脱水在 热会导致热衰竭。 然而，在这种情况下， 灾难性的结果通常是避免的：妥协显然是 使身体能够科普。 这些建议的目的 因此，实验是为了更好地理解身体的位置， 温度调节时，它是在竞争与其他，同时 自我平衡系统 我们会给受过训练的清醒的兔子注射 致热剂量的内毒素，并在一系列实验中，暴露 它们同时承受各种热负荷。 在随后的系列中，我们将 在这些处理之前，另外将动物饲养1天。 我们将分析兔子的反应， 每个调节系统的生理变量，即，为 体温调节，体温;对于感染，选择急性期 反应物;以及对于脱水，血浆渗透压。 结果应 有助于我们理解稳态相互作用的本质， 在复杂情况下的生理调节的一般背景下。

Appropriate and coordinated physiological adjustments continually occur to maintain the body's homeostasis. These activities involve multiple regulatory systems, interacting to preserve their optimal function. While well understood conceptually, few studies have, in fact, examined systematically the interrelationships among different regulatory systems when two or more physiological drives occur simultaneously. As the responses to different drives often utilize the same effector pathways, a potential for conflict is created when these drives are combined and impose concurrent stressful loads on the body, thereby competing for the same mechanisms at the same time. This raises the question: which homeostatic response has priority when competing demands are placed on shared mechanisms? A particular dilemma occurs with regard to body temperature control because the thermoregulatory system does not possess its own effectors, but rather depends on those of other systems, e.g., circulatory, respiratory, etc., which may also be required in the simultaneous defense of other variables. An example of a situation in which such a conflict may arise is when heat exposure, dehydration and infection occur together. These stressors, moreover, call, in part, for opposite responses by common effector mechanisms. Failure to adequately meet the needs could result in decompensation, e.g., dehydration in the heat leads to heat exhaustion. However, under such conditions, catastrophic out-comes usually are averted: compromises are evidently reached that allow the body to cope. The purpose of these proposed experiments, therefore, is to better understand the place of body temperature regulation when it is in competition with other, simultaneous homeostatic systems. We will inject trained, conscious rabbits with pyrogenic doses of an endotoxin, and in one series of experiments, expose them concurrently to various heat loads. In a subsequent series, we will additionally dehydrate the animals for 1 day prior to these treatments. We will analyze the rabbits' responses in terms of the fundamental physiological variable of each regulated system, i.e., for thermoregulation, body temperature; for infection, selected acute-phase reactants; and for dehydration, plasma osmolality. The results should contribute to our understanding of the nature of homeostatic interactions, in the general context of physiological regulation in complex situations.