Brunjes P C
University of Virginia, Charlottesville 22903.
Brain Res Brain Res Rev. 1994 Jan;19(1):146-60. doi: 10.1016/0165-0173(94)90007-8.
In most animals there is bilateral access of odorants to the olfactory sensory epithelium. Air enters the nose through two external nares and passes back through the nasal cavity, which is divided down the midline by a cartilaginous nasal septum. The olfactory mucosa, a sheet of ciliated bipolar receptor cells, is found in the caudal two thirds of the nasal cavity. Axons from the sensory cells project to an ipsilateral extension of the telencephalon known as the olfactory bulb. If a single external naris of a rat pup is surgically closed (usually via brief cauterization) on the day after the day of birth (P1) and the subject is examined on P30, the size of the ipsilateral olfactory bulb is reduced by approximately 25%. The large reduction in size, coupled with the clear lamination and other features of the olfactory system, indicates that the manipulation is an ideal preparation for examining the regulation of early growth. We know that both olfactory bulbs are of equal size at the time of occlusion, but that 30 days later there is a large discrepancy. What series of events produces the changes? The present paper outlines what is known about the anatomical, biochemical and physiological changes introduced by naris occlusion in order to lay a framework for further work.
在大多数动物中，气味分子可双侧进入嗅觉感觉上皮。空气通过两个外鼻孔进入鼻腔，然后向后穿过鼻腔，鼻腔由软骨性鼻中隔在中线处分为两半。嗅觉黏膜是一层带纤毛的双极受体细胞，位于鼻腔后部的三分之二处。感觉细胞的轴突投射到端脑的同侧延伸部分，即嗅球。如果在新生大鼠幼崽出生后第1天（P1）通过手术封闭其一个外鼻孔（通常通过短暂烧灼），并在P30对其进行检查，同侧嗅球的大小会减少约25%。嗅球大小的大幅减小，再加上嗅觉系统清晰的分层结构和其他特征，表明这种操作是研究早期生长调控的理想实验模型。我们知道在阻塞时两个嗅球大小相等，但30天后会出现很大差异。是一系列怎样的事件导致了这些变化呢？本文概述了关于鼻孔阻塞所引发的解剖学、生物化学和生理学变化的已知情况，以便为进一步的研究奠定基础。
