CARDIOVASCULAR CONCOMITANTS OF ULTRASONIC VOCALIZATIONS

首席调查员实验室最近的工作表明 与长期以来的观点相反，幼年老鼠表现出许多迹象 在适当的条件下测试时，温度调节成功。他们的 成功依赖于利用棕色脂肪组织内部产生的热量 (BAT)，以及这种热量传递到心脏。如果蝙蝠产热 心脏温度下降，心率减慢 对幼犬的维系能力造成了巨大的挑战 动脉压和静脉回流到心脏。此应用程序检查 这种体温调节-心血管相互作用的详细信息，还解决了 假设婴儿和成人发出的超声波发声 老鼠，通常被认为是情绪的有目的的交流信号 相反，痛苦是一种生理动作的声学副产品 被招募来在极端寒冷的环境中维持心血管功能 以及在其他具有生理挑战性的环境中。此应用程序的目标1 解决幼年大鼠增加的神经和激素机制 当心输出量减少时，对寒冷的外周抵抗。特定的 要研究的机制是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量。 目标2解决引起超声波的最接近的生理刺激 心血管功能的产生和相关的变化 伴随着超声波的生产。在这些实验中，静脉回流是(A) 使用多普勒血流探头测量和(B)使用药理学操作 和机械技术。最后，目标3解决了这样的假设，即 幼年大鼠和成年大鼠的超声发声是一致的。这 假设，基于两种发音之间的各种相似之处 通过确定实验性的静脉回流减少是否在成人中进行测试 足以唤起超声波发声，并通过评估 发热和交配期间的心血管变化，两种情况相关 用超声波来生产。该应用程序解决了以下基本方面 在婴儿和成人中使用行为、发育、 生理学方法。通过这些方法，对 幼年和成年哺乳动物调节心血管的不同机制 在生理和行为挑战期间的功能将会出现。

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.