Lu X Y, Ghasemzadeh M B, Kalivas P W
Graduate Program in Pharmacology/Toxicology, Washington State University, Pullman, WA 99164, USA.
Brain Res Mol Brain Res. 1999 Jan 8;63(2):287-96. doi: 10.1016/s0169-328x(98)00288-5.
Nucleus accumbens neurons are the targets of glutamatergic inputs. By coupling in situ hybridization for glutamate receptor mRNAs with retrograde transport of Fluoro-Gold, the present study examined the relationship between the distribution patterns of glutamate receptor subtypes/subunits and the output pathways of the nucleus accumbens to the ventral pallidum and ventral tegmental area. Following iontophoretic deposits of Fluoro-Gold into the ventral pallidum, neurons in both the nucleus accumbens shell and core were retrogradely labeled. A high percentage of accumbens neurons retrogradely labeled from the ventral pallidum were double-labeled for mRNAs encoding for mGluR5 (82+/-4.1%), NMDAR1 (71+/-3.5%), GluR1 (70+/-6.1%) and GluR2 (76+/-3.6%). No significant difference in the proportion of double-labeled neurons between the core and shell was observed. Following the deposit of Fluoro-Gold into the ventral tegmental area, only the accumbens shell neurons were retrogradely labeled. The proportion of neurons expressing NMDAR1, GluR1 and GluR2 were somewhat less in the projection to the ventral tegmental area compared to the ventral pallidum since approximately 60% of the neurons retrogradely-labeled from the ventral tegmental area expressed these transcripts. In contrast to the high proportion of mGluR5-containing neurons in the nucleus accumbens innervating the ventral pallidum, only half of the neurons projecting to the ventral tegmental area expressed mGluR5. These data show that accumbens neurons innervating the ventral pallidum and ventral tegmental area differ in the relative proportion of expressed mRNA encoding mGluR5, implying differential postsynaptic impact by glutamate transmission on neurons contributing to the two major efferent pathways of the nucleus accumbens.
伏隔核神经元是谷氨酸能输入的靶点。本研究通过将谷氨酸受体mRNA的原位杂交与荧光金的逆行运输相结合，研究了谷氨酸受体亚型/亚基的分布模式与伏隔核至腹侧苍白球和腹侧被盖区的输出通路之间的关系。在将荧光金离子导入腹侧苍白球后，伏隔核壳部和核心的神经元均被逆行标记。从腹侧苍白球逆行标记的伏隔核神经元中，高比例的神经元同时被标记为编码mGluR5（82±4.1%）、NMDAR1（71±3.5%）、GluR1（70±6.1%）和GluR2（76±3.6%）的mRNA。在核心和壳部之间，双标记神经元的比例未观察到显著差异。在将荧光金导入腹侧被盖区后，只有伏隔核壳部的神经元被逆行标记。与腹侧苍白球相比，投射到腹侧被盖区的神经元中表达NMDAR1、GluR1和GluR2的比例略低，因为从腹侧被盖区逆行标记的神经元中约60%表达这些转录本。与支配腹侧苍白球的伏隔核中含有高比例mGluR5的神经元不同，投射到腹侧被盖区的神经元中只有一半表达mGluR5。这些数据表明，支配腹侧苍白球和腹侧被盖区的伏隔核神经元在编码mGluR5的表达mRNA的相对比例上存在差异，这意味着谷氨酸传递对伏隔核两条主要传出通路中神经元的突触后影响不同。
