单耳堵塞对沙土鼠中脑下丘神经元谷氨酸受体密度的影响

目的考察单耳堵塞对沙土鼠中脑下丘(IC)背侧核(ICd)、外侧核(ICx)和中央核(ICc)部位谷氨酸(Glu)受体密度的影响。方法实验在30只沙土鼠上进行,雌雄不拘。分别在沙土鼠出生后3周龄(21dpn)、6周龄(42dpn)和成年(70dpn)实施单耳堵塞,4周后以体外受体标记放射自显影方法,考察比较IC左右侧各部位的银粒密度变化,并以此为相对指标,分析动物IC的神经元Glu受体密度的变化。结果成年组两侧IC神经元Glu受体密度没有显著性差异;3周龄和6周龄组呈现堵耳对侧的Glu受体密度明显少于堵耳同侧的不均衡分布(ICd部位:t=2.53,P=0.0186,t=1.77,P=0.0443;ICx部位:t=1.90,P=0.0359,t=2.03,P=0.0367;ICc部位:t=1.07,P=0.0332;t=2.35,P=0.0208)。并且3周龄组ICc部位的两侧Glu受体密度比值最小(0.61±0.03)。结论出生后6周前单耳堵塞对沙土鼠IC的神经元Glu受体发育具有明显影响,与Glu受体相关的下丘听觉功能发育将延续到出生后6周。

Effect of monaural plugging on the density of glutamate-receptor in the inferior collicular neurons of the gerbil

AIM:To study the effect of monaural plugging on the density of Glu- receptor in the inferior collicular (including ICd, ICx and ICc) neurons of the gerbil. METHODS:Thirty gerbils were used.4 weeks after plugging one side ear of gerbils at the different postnatal ages (21,42 and 70 dpn), the autoradiographaic technique was used to observe and compare the silver density which represented the Glu receptor of every section in the inferior collicular neurons in the different groups of gerbils. RESULTS:In the adult- plugging groups, the densities of the Glu receptor in the bilateral IC neurons showed no difference.In the 3- week- plugging and 6- week- plugging groups,the density of Glu- receptor in the contralateral neurons was significantly lower than that in neurons of plugging side(ICd:t=2.53,P=0.018 6;t=1.77,P=0.044 3;ICx:t=1.90,P=0.035 9, t=2.03,P=0.036 7;ICc: t=2.95,P=0.017 5,t=2.35,P=0.020 8,moreover,in ICc section of the 3- week plugging group the density ratio of Glu receptor of two sides was the smallest (0.61± 0.03). CONCLUSION:The monaural plugging within 6 weeks postnatally has significant effect on the density of Glu- receptors in the inferior collicular neurons.The auditory functional development of IC related to Glu receptor is extend to 6 weeks postnatal.