Modulatory effect of neurokinin-1 and non-N-methyl-D-aspartate receptors on cardiosomatic reflex in rat spinal cord / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the role of neurokinin-1 (NK1) receptor and non-N-methyl-D-aspartate (non-NMDA) receptor in modulating the cardiosomatic reflex in the spinal cord of rat.</p><p><b>METHODS</b>The effects of intrathecal injection of NK1 receptor agonist Sar-SP and antagonist CP-96345 and non-NMDA receptor agonist NMDA and antagonist 6, 7-dinitro-1,4-dihydro-quinoxaline-2,3-dione (DNQX) on the cardiosomatic reflex were observed in rats. The changes of the cardiosomatic reflex were monitored by observing the electromyogram (EMG) responses of the dorsal spinotrapezius muscle to intrapericardial bradykinin (BK) injection.</p><p><b>RESULTS</b>Intrathecal injection of Sar-SP significantly facilitated EMG responses to intrapericardial BK injection (P<0.05), which was completely blocked by intrathecal injection of NK1 antagonist CP-96345. Similarly, intrathecal injection of NMDA obviously facilitated the EMG responses (P<0.05), which was partially reversed by intrathecal injection of non-NMDA receptor antagonist DNQX. Intrathecal injection of Sar-SP along with NMDA significantly increased EMG as compared with single administration of Sar-SP or NMDA (P<0.05).</p><p><b>CONCLUSION</b>The spinal cord levels of NK1 receptor and non-NMDA receptor are involved in the modulation of the cardiosomatic reflex in rats.</p>