Functional Morphology of Vomeronasal Chemoreception in Squamate Reptiles

有鳞爬行动物犁鼻化学感受的功能形态学

• 批准号: 9601173
• 负责人: Kurt Schwenk
• 金额: $ 11.48万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9601173&HistoricalAwards=false
• 关键词: Functional; Morphology; Vomeronasal; Chemoreception; Squamate

IBN-9601173 Schwenk Squamate reptiles (lizards and snakes) have figured prominently in the growth of biological thought over the last fifty years. In particular, they have served as model organisms in studies that have shaped the field of vertebrate ecology, strongly influencing the development of modern ecological theory. It is now universally acknowledged that much of the behavioral ecology of lizards and snakes is directed by the chemical senses, especially the vomeronasal system (VNS). Therefore, elucidation of VNS function is a desirable goal within this broader context. The VNS is mediated by paired sensory receptors called the vomeronasal (or Jacobson's) organs (VNO) which lie in the snout just above the palate. In squamates the VNO are separated from the nasal cavities but open directly to the oral cavity through two tiny holes in the palate. They are stimulated by a unique behavior called tongue-flicking (TF) during which the tongue is protruded and oscillated to varying degrees. The tongue tip samples environmental chemicals extra-orally, either from the air or from the ground, and delivers these chemicals to the openings in the palate where they make their way to the VNO. The study will elucidate the anatomical and functional bases of VNS function in a representative species, the Gila monster (Heloderma suspectum). Gila monsters are an ideal study species for VNS function because they retain an intermediate morphology of the chemosensory apparatus that can serve as a functional baseline for future comparative studies. By embodying both primitive and derived features, their morphology and behavior provides information that can be generalized up and down the squamate evolutionary tree. The study will use dissection, histology and electron microscopy to examine the gross and microscopic anatomy of the tongue- vomeronasal system. The morphological mode l generated from these data will be combined with functional data derived from high speed cinegraphic (slow motion movie) and cineradiographic (x-ray movie) analyses to create a functional-morphological model of (1) tongue protrusion and oscillation; (2) environmental chemical sampling; (3) chemical delivery to the VNO. This model of VNS function will be supplemented with a theoretical/mathematical model of how chemical molecules diffuse into the fluid coating the tongue surface so that chemicals can be concentrated on the tongue during a tongue-flick. By clarifying the mechanism of the most fundamental sensory system in squamate reptiles, an important model group, this study should contribute substantively to our further understanding of how this and other animal groups diversify through time.

IBN-9601173 Schwenk鳞状爬行动物（蜥蜴和蛇）在过去的五十年中在生物学思想的增长中显着地发现。 特别是，它们是塑造脊椎动物生态学领域的研究中的模型生物，强烈影响了现代生态理论的发展。 现在普遍认为，蜥蜴和蛇的行为生态学的许多行为是由化学感官指导的，尤其是沃梅纳纳纳斯系统（VNS）。 因此，在这种更广泛的背景下，阐明VNS功能是一个理想的目标。 VNS是由称为Vomeronasal（或Jacobson's）器官（VNO）的配对感官受体介导的，该器官位于口感上方的鼻子中。 在鳞状体中，VNO与鼻腔分离，但通过口感直接向口腔开放。 它们受到一种独特的行为，称为舌头闪光（TF），在此过程中，舌头被伸出并在不同程度上振荡。 舌头尖端从空气或从地面上进行了方面的环境化学品采样，并将这些化学物质交付给味蕾的开口，在那里它们进入VNO。 该研究将阐明代表性物种吉拉怪物（Heloderma suspectum）中VNS功能的解剖和功能碱基。 吉拉怪物是VNS功能的理想研究物种，因为它们保留了化学感应设备的中间形态，可以用作将来比较研究的功能基线。 通过体现原始特征和衍生特征，它们的形态和行为提供了可以在鳞状进化树上上下概括的信息。 这项研究将使用解剖，组织学和电子显微镜检查舌 - 溶血系统的总体和微观解剖结构。 这些数据产生的形态模式将与来自高速电影（慢动作电影）和灰影（X射线电影）分析得出的功能数据结合使用，以创建（1）舌头突出和振荡的功能形态学模型； （2）环境化学抽样； （3）化学传递到VNO。 这种VNS功能模型将补充一个理论/数学模型，即化学分子如何扩散到舌表面的流体涂层中，从而使化学物质可以在舌粘合期间集中在舌头上。通过阐明重要模型组中最基本的感觉系统的机制，这项研究应实质上有助于我们进一步理解该动物和其他动物群体如何随着时间的流逝而多样化。