Wilson D A, Sullivan R M
Department of Zoology, University of Oklahoma, Norman 73019, USA.
J Neurosci. 1995 Aug;15(8):5574-81. doi: 10.1523/JNEUROSCI.15-08-05574.1995.
Wistar rats had a single nare occluded on postnatal day 30, depriving the ipsilateral olfactory bulb of odor stimulation. The deprivation lasted for either 1-2 months (short-term) or 12 months (long-term). As previously reported, deprivation greatly reduced tyrosine hydroxylase immunoreactivity (the rate limiting enzyme for dopamine synthesis) in the glomerular layer of the ipsilateral olfactory bulb. The nare was then reopened and odor response patterns of mitral/tufted cells were examined. The proportion of mitral/tufted cell single-units responding to a single odor was enhanced by deprivation. Furthermore, the proportion of mitral/tufted cells responding to more than one odor was increased by deprivation, suggesting a decrease in discrimination. Finally, in undeprived bulbs, the dopamine D2 receptor antagonist spiperone mimicked the effects of deprivation on mitral/tufted cell odor response patterns. The results are interpreted as an activity-dependent dopamine modulation of lateral and feedback inhibition in the olfactory bulb, and are compared with similar events in the dark-adapted retina.
出生后第30天，Wistar大鼠的一侧鼻孔被堵塞，使同侧嗅球无法接受气味刺激。剥夺持续1至2个月（短期）或12个月（长期）。如先前报道，剥夺极大地降低了同侧嗅球肾小球层中酪氨酸羟化酶免疫反应性（多巴胺合成的限速酶）。然后重新打开鼻孔，并检查二尖瓣/簇状细胞的气味反应模式。剥夺增加了对单一气味作出反应的二尖瓣/簇状细胞单单位的比例。此外，剥夺增加了对多种气味作出反应的二尖瓣/簇状细胞的比例，表明辨别能力下降。最后，在未被剥夺的嗅球中，多巴胺D2受体拮抗剂螺哌隆模拟了剥夺对二尖瓣/簇状细胞气味反应模式的影响。这些结果被解释为嗅球中依赖活动的多巴胺对侧向和反馈抑制的调节，并与暗适应视网膜中的类似事件进行了比较。
