Abstract:

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 (P<0.05);the CMR in DCPG group was increased (P<0.05)； the CMR in   MSOP group after injection of 20 nmol MSOP had no change (P>0.05);the CMR in   MSOP group after injection of 100 nmol MSOP was increased (P<0.05);the CMR in MSOP group after injection of 20 nmol MSOP followed L-AP4 or AMNO82 had no change (P>0.05).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.

Key words:  , nucleus tractus solitarius, cardiosomatic motor reflex, metabotropic glutamate receptors