CARDIOVASCULAR CONCOMITANTS OF ULTRASONIC VOCALIZATIONS

首席研究员实验室最近的工作表明， 与长期以来的观点相反，幼鼠表现出许多迹象， 在适当的条件下测试时，成功的体温调节。他们的 成功取决于利用褐色脂肪组织在体内产生热量 (BAT)以及将热量输送到心脏。如果BAT产热 心脏温度下降，心率下降， 这对幼犬维持 动脉压和静脉回流到心脏。该应用程序检查 这种温度调节心血管的相互作用的详细，也地址 婴儿和成人发出的超声波发声 老鼠，通常被认为是有目的的情感交流信号， 痛苦，而是一种生理动作的声学副产品， 在极度寒冷的环境中维持心血管功能 以及其他生理上具有挑战性的环境中。本申请的目的1 解决了神经和激素机制，其中幼鼠增加 当心输出量减少时，外周对寒冷的抵抗力。具体 要检查的机制是α-1肾上腺素受体，血管紧张素II和 加压素通过有选择地封锁这些系统中的每一个，以及 同时阻断所有三个系统，心脏之间的相互作用 检查心率、动脉压、静脉回流和超声产生。 目标2针对引起超声的近端生理刺激 生产和心血管功能的相关变化， 伴随着超声波的产生。对于这些实验，静脉回流是（a） 使用多普勒血流探针测量和（B）使用药理学方法操作 和机械技术。最后，目标3提出了一个假设，即 幼年大鼠和成年大鼠超声发声具有同源性。这 基于两种发音之间的各种相似性， 在成年人中进行测试，以确定静脉回流的实验性减少是否 足以引起超声波发声， 发热和交配期间的心血管变化，两种情况相关 超声波生产。本申请涉及以下基本方面： 使用行为，发育， 生理学方法。通过这些方法， 婴儿和成年哺乳动物调节心血管的不同机制 在生理和行为挑战中的功能将出现。

Recent work in the Principal Investigator's laboratory has shown that infant rats, contrary to a long-held view, exhibit many signs of successful thermoregulation when tested under appropriate conditions. Their success depends on the internal production of heat using brown adipose tissue (BAT), as well as the delivery of this heat to the heart. If BAT thermogenisis is not adequate and heart temperature decreases, cardiac rate decreases as well, resulting in significant challenges to the pup's ability to maintain arterial pressure and venous return to the heart. This application examines this thermoregulation-cardiovascular interaction in detail, and also addresses the hypothesis that the ultrasonic vocalizations emitted by infant and adult rats, typically assumed to be purposeful communicatory signals of emotional distress, are instead the acoustic by-products of a physiological maneuver that is recruited to maintain cardiovascular function during extreme cold exposure and in other physiologically challenging contexts. Aim 1 of this application addresses the neural and hormonal mechanisms by which infant rats increase peripheral resistance to the cold when cardiac output is decreasing. Specific mechanisms to be examined are alpha-1 adrenoreceptors, angiotensin II and vasopressin. Through selective blockade of each of these systems, as well as simultaneous blockade of all three systems, the interactions between cardiac rate, arterial pressure, venous return and ultrasound production are examined. Aim 2 addresses the proximate physiological stimuli that elicit ultrasound production and the associated changes in cardiovascular function that accompanies ultrasound production. For these experiments, venous return is (a) measured using Doppler flow probes and (b) manipulated using pharmacological and mechanical techniques. Finally, Aim 3 addresses the hypothesis that the infant and adult rat's ultrasonic vocalizations are homologous. This hypothesis, based on a variety of similarities between the two vocalizations is tested in adults by determining whether experimental decreases in venous return are sufficient to evoke ultrasonic vocalizations and by assessing cardiovascular changes during fever and copulation, two contexts associated with ultrasound production. This application addresses basic aspects of homeostatic regulation in infants and adults using behavioral, developmental, physiological approaches. Through these approaches, an integrated view of the varied mechanisms by which infant and adult mammals regulate cardiovascular function during physiological and behavioral challenges will emerge.