芍药甘草汤对中枢性肌张力增高大鼠脑内氨基酸及其受体的影响

Effects of Shaoyao Gancao decoction on contents of amino acids and expressions of receptors in brains of spastic paralysis rats

探讨芍药甘草汤对中枢性肌张力增高大鼠模型的神经递质及其受体的影响。采用线拴法所致的脑卒中恢复期痉挛性肌张力增高大鼠模型,以巴氯芬为对照,实验组给予芍药甘草汤3∶1配伍比例,给药3周后测定其神经功能评分、肌张力、痛阈的变化,并采用HPLC测定大脑皮层GABA,Gly,Glu,Asp含量,免疫组化法测定大脑皮层GABA受体Aα1,B与NMDA受体亚基NR1,NR2A,NR2B蛋白表达。结果显示芍药甘草汤3∶1配伍剂量组对脑卒中后痉挛偏瘫状态有较好的改善作用,能显著改善神经症状(P<0.01),降低肌张力(P<0.01),改善痛域(P<0.05);能够显著增加脑内抑制性氨基酸GABA,Gly的含量(P<0.01),对于兴奋性氨基酸Glu,Asp有降低的趋势,但没有统计学意义;能够显著增强大脑抑制性神经递质受体GABA受体Aα1和B的表达(P<0.05),并减少大脑兴奋性神经递质受体NMDA各亚型NR1,NR2A,NR2B的表达(P<0.05)。研究表明,芍药甘草汤3∶1配伍剂量具有较好的解痉止痛之效,不仅能够增加脑卒中后痉挛状态大鼠脑内抑制性氨基酸的水平,同时还可增加其受体的表达,从而增加抑制性神经信号转导的强度;对于脑内兴奋性氨基酸水平虽然没有显著性作用,但也有降低的趋势,同时对于兴奋性氨基酸受体的表达也有抑制作用,从而减弱兴奋性神经信号转导的强度,减轻兴奋性神经毒性。结果表明,芍药甘草汤可通过调节脑内抑制性和兴奋性神经能系统的平衡,从而达到缓解脑卒中痉挛状态,起到柔筋止痉的作用。

To explore the effects of Shaoyao Gancao decoction on contents of amino acids and expressions of receptors in the brains of spastic paralysis rats, the spastic paralysis rat models of stroke convalescence were made by line tethering method. Baclofen was used as the control group, and the experiment group received Shaoyao Gancao decoction at 3：1 proportions. After 3 weeks, the neurobehavioral scores, muscular tension and pain threshold were measured and compared. High performance liquid chromatography （HPLC） was used to detect the contents of GABA, Gly, Glu, Asp in cerebral cortex. The protein expressions of GABA receptors Aa1, B; NMDA receptor NR1, NR2A and NR2B in cerebral cortex were determined by immunohistochemistry assay. The results showed that the Shaoyao Gancao decoction at 3：1 proportion could improve the spastic paralysis state after stroke, significantly improve neurological symptoms （P 〈 0. 01 ）, decrease muscular tension （P 〈 0. 01 ） and improve pain threshold （P 〈 0. 05 ） as compared with model group. Simultaneously, the contents of inhibitory amino acids GABA and Gly were increased significantly （P 〈0. 01 ） , while with a decrease tendency in excitatory amino acids Glu and Asp （with no statistical significance）. In addition, it could significantly increase the protein expressions of neurotransmitter GABA receptors Aal, and B （ P 〈 0. 05 ） ; reduce the expressions of neurotransmitter NMDA receptors NR1, NR2A and NR2B （P 〈 0. 05）. These results suggested that the Shaoyao Gancao decoction at 3 ： 1 proportion could effectively relieve spasm and pain. The mechanism might be associated with increasing the contents of inhibitory amino acids and increasing the expressions of their receptors in spastic paralysis rats after stroke, which would consequently enhance the signal transduction of inhibitory amino acids. Meanwhile, there was a decrease tendency in excitatory amino acids, although no significant effect was observed, and it could suppress the expressions of excitatory amino acids receptors, thus weaken the excitatory signal transduction. Thereby the neurotoxicity was relieved eventually. These findings indicated that Shaoyao Gancao decoction could regulate the balance of neurotransmitter system to relieve the spasticity, and eventually achieve tendon tonifying and spasm relieving effect.