AUDITORY ANATOMY IN AGING RATS WITH EXTENDED LIFESPANS

拟议研究涉及的主要问题是 关于听觉的节奏和严重程度是否 寿命延长的动物的细胞变化会改变 持续时间超过常规限制。 所提出的研究将实现这种寿命的延长 通过长期的食物限制，使用一种 本身并不会导致虚弱或缺陷。这项工作 采用解剖学和功能学技术，与 观察脏器和全身病理，检查大鼠 它们的寿命远远超过了正常的极限。这个 这项工作的基本原理包括：(1)价值评估 从神经保护的角度来延长寿命， (2)建立一个重要的衰老新模型 研究。 要检查的具体系统是听觉系统，一个 一种在人类身上表现出显著和可靠的功能的系统 随着年龄的增长，结构退化。观察到的 将集中在听觉通路的两端，即耳蜗处 和听觉皮质。使用光学和电子显微镜，年龄- 相关的变化将在感觉毛细胞中进行分析， 突触、螺旋神经节细胞、血管纹和血管 大脑皮层的。皮质分析将包括高尔基体的使用 允许超微结构检查的去浸渍技术 明确识别出的皮质细胞类型。结果将是 与脑干听觉诱发结果密切相关 答复，以及根据以下分析解释的结果 器官系统病理学。 需要检验的主要假设如下：(1) 寿命的绝对长度是一个重要的变量 与年龄相关的细胞变化的程度；(2)限制性的变化 大鼠按正常节奏发生，但比AD大鼠严重 丽贝卡。喂老鼠。

The major issue addressed by the proposed research is the question of whether the tempo and the severity of auditory cellular changes are altered in animals whose lifespans are prolonged beyond conventional limits. The research proposed will achieve this prolongation of lifespan by means of chronic food restriction, using a regimen that does not in and of itself lead to debility or deficiency. The work employs anatomical and functional techniques, correlated with observations of organ and systemic pathology, to examine rats whose lifespans are extended well beyond normal limits. The rationale underlying the work involves (1) assessment of the value of lifespan extension from the standpoint of neural preservation, and (2) establishment of an important new model for aging research. The specific system to be examined is the auditory system, a system which, in humans, exhibits marked and reliable functional and structural degradation with advancing age. The observations will focus on the two ends of the auditory pathway, the cochlea and auditory cortex. Using light and electron microscopy, age- related changes will be analyzed in the sensory hair cells, synapses, spiral ganglion cells, stria vascularis, and blood vessels of the cortex. The cortical analysis will include the use of Golgi deimpregnation techniques to permit ultrastructural examination of specifically identified cortical cell types. The results will be closely correlated with the results of brainstem auditory evoked responses, and the findings interpreted in the light of analyses of organ system pathology. Among the major hypotheses to be tested are the following: (1) the absolute length of the lifespan is a significant variable in extent of age-related cellular change; (2) changes in restricted rats occur at normal tempo, but are more severe than those in ad lib. fed rats.