南方医科大学学报

南方医科大学学报 ›› 2014, Vol. 34 ›› Issue (01): 8-.

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中脑导水管周围灰质腹外侧区促代谢型谷氨酸受体亚型7和8对大鼠心脏-躯体运动反射的双向调节作用

孙 娜，孔令恒，牛利刚，朱娟霞，徐 燕，杜剑青   

  • 出版日期:2014-01-20 发布日期:2014-01-20

Ventrolateral periaqueductal gray metabotropic glutamate receptor subtypes 7 and 8
mediate opposite effects on cardiosomatic motor reflex in rats

  • Online:2014-01-20 Published:2014-01-20

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摘要： 目的观察中脑导水管周围灰质腹外侧区（VL-PAG）内促代谢型谷氨酸受体亚型7（mGluR 7）和8（mGluR 8）对大鼠心脏-
躯体运动反射（CMR）的调节作用。方法通过心包插管术制作CMR大鼠模型，在VL-PAG内分别注射mGluR 7和mGluR 8的
激动剂AMN082和DCPG，观察其对大鼠CMR的调节作用；同时电损毁延髓头端腹内侧区（rostroventral medulla, RVM）亚核中
的中缝大核或双侧网状巨细胞核，观察VL-PAG对大鼠CMR的下行调控作用。结果AMN082选择性激活VL-PAG内mGluR
7后，对辣椒素诱发的CMR具有明显的易化作用（P<0.05）；与之相反，DCPG激活VL-PAG内mGluR 8对CAP诱发的CMR具有
明显的抑制作用（P<0.05）；这种易化或抑制效应均可被其拮抗剂MSOP完全拮抗；损毁大鼠VL-PAG的主要中继亚核中的中缝
大核后，VL-PAG内AMN082微注射所产生的易化效应没有受到明显的影响（P>0.05），VL-PAG内DCPG微注射所产生的抑制
效应被部分地减弱（P<0.05）；而双侧网状巨细胞核损毁后，AMN082微注射所产生的易化效应明显被减弱，同时DCPG所产生
的抑制效应也有所减弱。结论VL-PAG内mGluR 7和mGluR 8对大鼠CMR具有易化和抑制双向调节效应，而这种双向调节
效应很可能是通过RVM的不同亚核、不同神经元的激活而实现的。

Abstract: Objective To investigate the role of ventrolateral periaqueductal gray (VL-PAG) metabotropic glutamate receptors
subtype 7 and 8 (mGluR 7/8) in descending modulation of cardiosomatic motor reflex (CMR) in rats. Methods AMN082
(agonist of mGluR 7) and DCPG (agonist of mGluR 8) were injected into the VL-PAG of a rat model of CMR to observe their
effects in modulating CMR. The raphe magnus nucleus (NRM) or the gigantocellular reticular nucleus (Gi) was then damaged,
and the changes in VL-PAG descending modulation were observed. Results Selective activation of mGluR 7 of the VL-PAG by
AMN082 obviously facilitated capsaicin (CAP)-induced CMR (P<0.05), which was suppressed by DCPG-induced mGluR 8
activation (P<0.05). These facilitatory or inhibitory effects were completely reversed by group III mGluR antagonist MSOP.
Damaging the NRM of VL-PAG main relay nucleus did not significantly affect the facilitatory effect produced by AMN082
microinjection (P>0.05), but partially attenuated the inhibitory effect of DCPG microinjection (P<0.05). Both the facilitatory
effect of AMN082 and the inhibitory effect of DCPG were reduced obviously after bilateral Gi damage (P<0.05). Conclusion
VL-PAG mGluR 7 and mGluR 8 mediate biphasic regulation of CMR in rats probably through activation of different sub-nuclei
and different neurons in the rostroventral medulla.