Hormonal Control of an Avian Neuromuscular System

在许多鸟类中，荷尔蒙对行为的控制延伸到生理上复杂的求偶表现，但尚未得到很好的理解。在巴拿马的一种热带鸟类——金领金丝雀中，雄性会发出特有的响亮的振翅动作，作为求偶舞蹈的一部分。雄性有三块翅膀肌肉，在大小和/或生化组成上与雌性不同，脊髓中的运动神经元显示出比雌性更多的雄激素性类固醇激素分子受体，这表明manakins是评估类固醇对复杂周围神经肌肉系统控制的有用模型。该项目整合了分子生物学、生物化学、解剖学和行为学方面的工作，以确定激素如何在这个两性二态系统中季节性地调节这种行为。基因表达和代谢酶活性提供了类固醇激素及其受体分布的数据，并在男性和女性脊髓之间进行了比较。确定哪些特定的肌肉参与了翅膀的拍打，可以确定肌肉的性别二态性和脊髓中雄激素敏感运动神经元是如何与这种行为相关的。使用雄激素阻滞剂测试季节性波动的雄激素是否会导致脊髓和肌肉的解剖和生理在繁殖季节和非繁殖季节发生变化。这项工作的结果将为类固醇激素如何作用于周围神经肌肉系统以控制行为提供重要信息。这项工作的影响从神经内分泌学扩展到生殖生理学和进化生物学，并可能在鸟类育种中使用。该项目还包括极好的学生培训机会和与巴拿马的重要国际组成部分。

Hormonal control of behavior extends to physically complex courtship displays in many bird species, but is not well understood. In a tropical bird of Panama, the golden-collared manakin, the males execute characteristic loud wingsnaps as part of a courtship dance. The males have three wing muscles that differ from those in females in size and/or biochemical composition, and there are motor neurons in the spinal cord that show more molecular receptors for androgenic sex steroid hormones than in females, suggesting that manakins are useful models for evaluating steroid control of complex peripheral neuromuscular systems. This project integrates molecular biology, biochemistry, anatomy and behavioral work to determine how hormones seasonally regulate this behavior in this sexually dimorphic system. Gene expression and metabolic enzyme activity provide data on distributions of steroid hormones and their receptors, and for comparisons between male and female spinal cords. Determining which particular muscles are involved in the wingsnap allows determining how sexual dimorphism of the muscles and the androgen-sensitive motoneurons in the spinal cord are relevant to the behavior. Use of androgen-blocking agents tests whether seasonally fluctuating androgens may cause changes across the breeding and non-breeding seasons in the anatomy and physiology of the spinal cord and muscles. Results from this work will provide important information on how steroid hormones act on this peripheral neuromuscular system to control behavior. The impact of this work extends beyond neuroendocrinology to reproductive physiology and evolutionary biology, and may have use in bird breeding. This project also involves excellent opportunities for student training and an important international component with Panama.