Benson T E, Ryugo D K, Hinds J W
J Neurosci. 1984 Mar;4(3):638-53. doi: 10.1523/JNEUROSCI.04-03-00638.1984.
Closure of the nostril by electrocauterization on postnatal day (PN) 1 or 2 was used to study effects of olfactory deprivation on developing olfactory epithelium (OE) and bulb (OB) in CD-1 mice. No damage was observed in OE sections 1 or 3 days after closure, and at PN 30 no difference was found in the number of OE receptors between closed and open sides. Odor deprivation and a decrease in functional activity in experimental bulbs was evident from deoxyglucose autoradiographs at PN 21 and PN 30. At PN 30 deprived bulbs appeared smaller than nondeprived bulbs. Nissl stains revealed normal cytoarchitecture, but a protargol stain demonstrated fewer intraglomerular dendrites in deprived bulbs. At PN 30, volumes of deprived bulbs were 26% smaller than nondeprived bulbs. The volume of each bulbar lamina was 13 to 35% smaller than the comparable nondeprived lamina except for the ventricular/subependymal zone which was not significantly different between bulbs. Volumes of bulbs contralateral to the closed naris and the volumes of their laminae were not significantly different from control bulbs, suggesting no hypertrophy of nondeprived laminae. Deprivation did not affect the number of mitral cells seen at PN 30, their nuclear size, or their number of nucleoli. Lateral olfactory tract cross-sectional area was also unaffected by deprivation. Mitral cell perikaryal size, however, was smaller in deprived bulbs. Soma surface areal density of deprived mitral-to-granule cell synapses in deprived bulbs was 65% of the nondeprived density, while the density of granule-to-mitral cell synapses was only 46% of the nondeprived density. It is concluded that neonatal naris closure brings about a functional deprivation of the OB without receptor degeneration. Neonatal olfactory deprivation affects the perikaryal surface area but not the number of mitral cells. Also, deprivation markedly affects the reciprocal synapses between mitral and granule cells. Olfactory sensation thus appears necessary for normal development of OB neurons and synapses.
在出生后第1天或第2天通过电灼封闭鼻孔，以此来研究嗅觉剥夺对CD-1小鼠发育中的嗅上皮（OE）和嗅球（OB）的影响。封闭后1天或3天，在OE切片中未观察到损伤，并且在出生后第30天，封闭侧和开放侧的OE受体数量没有差异。从出生后第21天和第30天的脱氧葡萄糖放射自显影片可以明显看出，实验性嗅球存在气味剥夺和功能活性降低的情况。在出生后第30天，剥夺组的嗅球看起来比未剥夺组的小。尼氏染色显示细胞结构正常，但改良硝酸银染色显示剥夺组嗅球内肾小球状树突较少。在出生后第30天，剥夺组嗅球的体积比未剥夺组小26%。除了脑室/室管膜下区在两组嗅球之间无显著差异外，每个嗅球层的体积比相应的未剥夺层小13%至35%。封闭鼻孔对侧的嗅球及其各层的体积与对照嗅球无显著差异，这表明未剥夺层没有肥大现象。剥夺并未影响出生后第30天观察到的二尖瓣细胞数量、其核大小或核仁数量。外侧嗅束的横截面积也不受剥夺影响。然而，剥夺组嗅球中二尖瓣细胞的胞体大小较小。剥夺组嗅球中被剥夺的二尖瓣细胞与颗粒细胞突触的体细胞表面面积密度是未剥夺组密度的65%，而颗粒细胞与二尖瓣细胞突触的密度仅为未剥夺组密度的46%。研究得出结论，新生小鼠鼻孔封闭会导致嗅球功能剥夺但不会引起受体退化。新生期嗅觉剥夺会影响二尖瓣细胞的胞体表面积，但不会影响其数量。此外，剥夺显著影响二尖瓣细胞和颗粒细胞之间的相互突触。因此，嗅觉感觉似乎是嗅球神经元和突触正常发育所必需的。
