DEVELOPMENT OF AUTONOMIC AND BEHAVIORAL THERMOREGULATION

哺乳动物的体温调节通常分为两部分， 自主和行为。两种组分的特性良好 在成年人中已知，但它们在成年人中的协调性使得难以 辨别动物整合和协调反应的方式。 发展的方法在这方面是有用的，因为 新生哺乳动物具有不成熟的反应， 在相对短暂的发展过渡中协调。一个这样 最近在这个实验室里发现的一种转变， 在两到八天的年龄之间的体温调节反应。 这种转变很重要，因为它的发生表明了 体温调节激活不同于目前的那些 疑似具体来说，据信新生儿的产热 大鼠仅通过棕色脂肪的直接神经激活来激活 组织（BAT）。然而，这里假设， 肾上腺髓质嗜铬组织释放的儿茶酚胺 和/或Zuckerkandl器官，有助于BAT激活。是 进一步假设，从强大的BAT激活过渡到 出生一周内静音BAT激活的结果， 交感神经支配以及Zuckerkandl器官退化。 这些假设将使用药理学和外科学方法进行检验。 这些器官和系统在发育过程中的操作。并行 通过这些生理学研究，一种新的转头模式 涉及辐射热加固将用于调查 在产后同一时期发展热偏好。在 此外，由于这两种方法的综合是一个主要目标， 自主反应和行为反应之间的相互作用 将随着幼犬的成长而被研究据推测，协调 的生理和行为反应， 体温调节成分在产后第一周成熟。 最后，这些对一周大老鼠的跨学科研究可能提供 关于两个可比较的发展阶段的宝贵信息 在人类婴儿的四个月内，婴儿最有可能 婴儿猝死综合症

Mammalian thermoregulation is typically divided into two components, autonomic and behavioral. The characteristics of both components are well known in adults, but their coordination in adults makes it difficult to discern the ways in which animals integrate and coordinate responses. Developmental approaches are useful in this regard because altricial newborn mammals possess immature responses that become mature and coordinated during relatively brief developmental transitions. One such transition, recently identified in this laboratory, involves a diminution in thermoregulatory responsiveness between the ages of two and eight days. This transition is important because its occurrence suggests mechanisms of thermoregulatory activation that are different from those currently suspected. Specifically, it is believed that heat production in newborn rats is activated solely by direct neural activation of brown adipose tissue (BAT). It is hypothesized here, however, that circulating catecholamines, released from chromaffin tissue in the adrenal medulla and/or the organ of Zuckerkandl, contribute to BAT activation. It is further hypothesized that the transition from robust BAT activation at birth to muted BAT activation within one week results from developing sympathetic innervation as well as involution of the organ of Zuckerkandl. These hypotheses will be tested using pharmacological and surgical manipulations of these organs and systems during development. In parallel with these physiological investigations, a novel head-turning paradigm involving radiant heat reinforcement will be used to investigate the development of thermal preference over the same postpartum period. In addition, because a synthesis of these two approaches is one primary goal of this project, interactions between autonomic and behavioral responses will be investigated as pups develop. It is hypothesized that coordination of physiological and behavioral responses will emerge as both thermoregulatory components mature during the first week postpartum. Finally, these interdisciplinary studies of week-old rats may provide valuable information regarding the comparable developmental stage of two to four months in human infants, at which time infants are most at risk for Sudden Infant Death Syndrome.