Ventrolateral periaqueductal gray metabotropic glutamate receptor subtypes 7 and 8 mediate opposite effects on cardiosomatic motor reflex in rats
SUN Na
KONG Lingheng
NIU Ligang
ZHU Juanxia
XU Yan
DU Jianqing
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.
Keywords：ventrolateral periaqueductal grayrostroventral medullacardiosomatic motor reflexmetabotropic glutamate receptor 7metabotropic glutamate receptor 8electromyogram
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 8-13 )