大鼠孤束核内谷氨酸受体亚型对心脏伤害性感受信息的调控作用

Role of glutamate receptor subtypes in cardiac nociception in nucleus tractus solitarius in rats

目的:探讨大鼠孤束核(NTS)内谷氨酸受体亚型对心包内注射辣椒素诱发的心脏-躯体运动反射(CMR)的影响,阐明NTS对心脏伤害性信息调控的作用机制。方法:SD大鼠60只随机分为鹅膏蕈氨酸(IBO)组、谷氨酸组、5-甲基二氢丙环庚烯亚胺马来酸(MK-801)组、α-甲基,4-羧基苯丙氨酸(MCPG)组、MCPG联合MK-801组和6,7-二硝基喹喔啉-2,3-二酮(DNQX)组;各组大鼠孤束核内分别微量注射13mmol·L-1 IBO100nL,100、200、500mmol·L-1谷氨酸100nL,NMDA受体拮抗剂40和60mmol·100-1 MK-801 100nL,代谢型谷氨酸受体拮抗剂25和50mmol·L-1 MCPG 100nL,25mmol·L-1 MCPG 50nL联合40mmol·L-1MK-801 50nL,非NMDA受体拮抗剂20和50 mmol·L-1 DNQX 100nL;观察各组大鼠CMR的变化。结果:与对照组比较,IBO组大鼠CMR减少(P<0.05);谷氨酸组随着谷氨酸浓度的增加,大鼠CMR不断增加(P<0.05);MK-801和MCPG组CMR均减少(P<0.05);MCPG联合MK-801组CMR减少(P<0.05);DNQX组CMR无明显变化(P>0.05)。结论:NTS对心脏伤害性感受信息有易化调控作用,这种易化调节作用主要由NMDA和mGluRs受体介导。

Objective To study the role of glutamate receptor subtypes in nucleus tractus solitarius（NTS）in cardiac-somatic motor reflex （CMR）induced by intrapericardial administration of capsaicin,and to clarify the modulation mechanism of NTS to cardiac nociceptoion.Methods 60 SD rats were randomly divided into ibotenic （IBO）group, glutamate group, MK-801 group, MCGP group, MK-801 ＋ MCPG group and DNQX group. The NTS microinjected with 130 mmol·L-1 IBO 100 nL,100,200,500 mmol·L-1 L-glutamate 100 nL,NMDA receptor antagonist 40 and 60 mmol · L-1 MK-801 100 nL, metabotropic glutamate receptors antagonist 25 and 50 mmol·L-1 MCPG 100 nL,25 mmol· L-1 MCPG 50 nL plus 40 mmol· L-1 MK-801 50 nL,non-NMDA receptor antagonist 20 and 50 mmol·L-1 DNQX 100 nL,respectively.The changes of CMR of the rats in various groups were observed.Results Compared with control group,the CMR of the rats in IBO group was decreased （P〈0.05）;the CMR was increased as the concentration increased in glutamate group（P〈0.05）;the CMR in MK-801 and MCPG groups were decreased （P〈0.05）;the CMR in MK-801＋MCPG group was decreased （P〈0.05）;the CMR in DXQX group had no changes （P〉0.05）.Conclusion NTS play an facilictory role in cardiac＆amp;nbsp;nociception,and the NMDA receptors and mGluRs receptors mediate this facilitory modulation.