ABSTRACT
Objective To explore the role of metabotropic glutamate receptors (mGluRs)group Ⅲ and its subtypes mGluR7 and mGluR8 in nucleus tractus solitarius(NTS)in cardiac-somatic motor reflex (CMR),and to clarify the modulation role of mGluR Ⅲ and its subtypes in NTS in cardiac nociceptoion.Methods 40 SD rats were randomly divided into L-AP4 group,microinjection of mGluRs Ⅲ agonist L-AP4 0.1,1.0,10.0 or 20.0 nmol in NTS;AMN082 group,microinjection of mGluR7 agonist AMN082 1,2 or 4 nmol;DCPG group,microinjection of mGluR8 agonist DCPG 4, 6 or 8 nmol;MSOP group, microinjection of mGluR Ⅲ antagonist MSOP 20 or 100 nmol,20 nmol MSOP+410 nmol L-AP,20 nmol MSOP+2 nmol AMN082,20 nmol MSOP+6 nmol DCPG. The changes of CMR of the rats in various groups were observed.Results Compared with control,the CMR in L-AP4 and AMN082 groups was decreased (P0.05);the CMR in MSOP group after injection of 100 nmol MSOP was increased (P0.05).Conclusion The group Ⅲ mGluRs in the NTS play an inhibitory role in cardiac nociception, and mGluR7 has anti-nociceptive effects while mGluR8 has pro-nociceptive effects.
ABSTRACT
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 (P0.05).Conclusion NTS play an facilictory role in cardiac nociception,and the NMDA receptors and mGluRs receptors mediate this facilitory modulation.