Chemical lesioning and glutamate administration reveal a major role for the nucleus tractus solitarius in the cardiac-somatic reflex in rats

摘要: Many patients suffer from secondary muscle hyperalgesia after experiencing angina pectoris. In this study, we examined the role of nucleus tractus solitarius (NTS) and glutamate receptors in modulating cardiac-evoked induced by pericardial capsaicin, which was monitored recording electromyogram (EMG) activity spinotrapezius anesthetized rat. Unilateral chemical lesioning commissural NTS with neurotoxin ibotenic acid significantly depressed cardiac-somatic reflex; EMG responses decreased to 56.4 ± 6.9% that controls (5 5). Microinjection excitatory amino glutamate, at 10, 20, 50 nmol, into increased response, a dose-dependent manner, 116.9 4.9%, 143.9 10.2%, 214.2 15.8% (n=8), respectively, controls. contrast, microinjection N-methyl-D-aspartate (NMDA) receptor antagonist (+)-5-methyl-10, 11-dihydro-5H-dibenzo [a, d]-cyclohepten-5,10-imine maleate (MK-801) 4 6 response 45.2 10.6% 36.8 14.3%, (n=8 for each dose). Similarly, metabotropic (mGluR) (RS)-a-methyl-4-carboxyphenylglycine (MCPG), 2.5 5 65.2 16.3% 57.0 4.2%, When combination MK-801 MCPG administrated, further 22.5 13.2% (n=6) However, administration non-NMDA 6, 7-dinitroquinoxaline-2, 3-dione (DNQX), 2 had no effect on response. These results suggest is involved facilitation reflex, NMDA mGluRs play an important mediating effect.