目的研究高位脊髓损伤(spinal cord injury,SCI)后心血管中枢孤束核(solitary tract nucleus,NTS)氨基酸递质受体表达变化。方法采用SD大鼠T4脊髓横断模型,分为SCI组(n=5)和假手术组(n=5),动态观察SCI后1、2、3、4、6周血压和心率的变化及用蛋白质印迹法检测NTS区兴奋性递质谷氨酸(glutamate)受体N-甲基-D-天冬氨酸受体1(NMDA-R1)和抑制性递质γ-氨基丁酸A受体α1(GABAA-α1)在SCI后的变化特点。结果 SCI后,大鼠平均动脉压于1-3周明显下降(P〈0.05),4周后逐渐恢复正常;心率于1-4周明显升高(P〈0.05),6周时恢复正常。蛋白质印迹分析检测发现,NMDA-R1表达于1-4周明显升高(P〈0.05),6周时恢复正常;GABAA-α1表达于2周时明显升高,4、6周明显下降(P〈0.05);NMDA-R1与GABAA-α1的相对比值在损伤后即明显升高(P〈0.05)。结论 SCI后心血管中枢NTS区主要功能受体发生适应性变化,可能有助于纠正SCI后心血管功能紊乱。
Objective To investigate the changes of the amino acid receptors in solitary tract nucleus(NTS)of rats after spinal cord injury(SCI).Methods The rat model of T4 spinal cord transection was used in this study.The study was divided into SCI group(n=5)and Control group(n=5).Changes in mean arterial pressure(MAP)and heart rate(HR)were observed at 1,2,3,4,and 6 weeks after SCI;and the protein expression of the glutamate N-methyl-D-aspartate receptor 1(NMDA-R1)and gamma-aminobutyric acid receptor Aα1(GABAA-α1)in the NTS were detected by Western blotting analysis at different time points.Results The MAP level was significantly decreased at 1-3 weeks after SCI(P0.05),and it gradually recovered 4 weeks after SCI;the HR was significantly increased 1-4 weeks after SCI(P0.05)and recovered at the 6th week.The results of Western blotting analysis showed that the protein expression of GABAA-α1 was significantly increased 2 weeks after SCI and significantly reduced at 4 and 6 weeks after SCI(P0.05).Moreover,the ratio of NMDA-R1 to GABAA-α1 expression in NTS was significantly elevated after SCI(P0.05).Conclusion The adaptable changes of important receptors in the NTS following SCI may improve SCI-induced cardiovascular dysfunction.