论文部分内容阅读
目的 利用脑型及味型mGluR4在体内外的表达 ,检测两种受体结构功能上的差异 ,从而证实它们在信号转导功能上的不同。 方法 将克隆得到的脑型及味型mGluR4分别通过脂质体介导转染CHO细胞。在L MSG和L AP4的作用下 ,检测两种受体的功能。利用WesternBlot及原位杂交技术 ,分别检测它们在体内外的表达。 结果 转染脑型及味型mGluR4的CHO细胞 ,表达两种不同分子量的免疫活性蛋白 ,其中脑型分子量约为 12 0kD而味型约为 6 8kD。在L MSG和L AP4作用下 ,味型mGluR4对刺激物反应的浓度远高于脑型mGluR4。对大鼠脑组织及舌味蕾的原位杂交证明 ,mGluR4在小脑颗粒细胞有很高的表达 ,而在味蕾细胞表达率较低 ,阳性细胞仅占味蕾细胞的 5 %。 结论 味组织中的mGluR4与脑组织中mGluR4在结构和功能上有明显不同。味型mGluR4特异性表达于味蕾细胞 ,在高于脑内的浓度下 ,结合细胞外的谷氨酸 ,通过降低cAMP的浓度引发味觉信号转导。是谷氨酸味觉的特异性受体
Objective To detect the functional differences between the two receptors in vitro and in vivo by using brain-type and taste-type mGluR4 to confirm the difference in signal transduction function. Methods The cloned cerebral and taste mGluR4 cells were transfected into CHO cells by liposome respectively. The function of both receptors was tested by LMSG and LAP4. Western Blot and in situ hybridization were used to detect their expression in vitro and in vivo. Results The CHO cells transfected with both mGluR4 and brains expressed two kinds of immunocompetent proteins of different molecular weights. The molecular weight of the brain was about 120 kD and the taste was about 68 kD. Under the action of L MSG and L AP4, the concentration of mGluR4 in taste response to stimuli is much higher than that of brain mGluR4. In situ hybridization of rat brain tissue and the tongue taste bud demonstrated that mGluR4 is highly expressed in cerebellar granulosa cells and low in taste bud cells, with positive cells accounting for only 5% of taste bud cells. Conclusion The structure and function of mGluR4 in brain tissue and mGluR4 in brain tissue are obviously different. Taste mGluR4 is specifically expressed in taste bud cells, binds extracellular glutamate at higher concentrations in the brain, and initiates taste signal transduction by decreasing the cAMP concentration. Is a specific receptor of glutamic acid taste