Wilson L B, Crews A D
Department of Physiology, University of South Alabama College of Medicine, 307 University Blvd., Mobile, AL 36688, USA.
Brain Res. 1998 Oct 5;807(1-2):222-7. doi: 10.1016/s0006-8993(98)00800-2.
The purpose of this study was to examine the influence of NMDA receptor blockade in the dorsal horn of adjacent spinal segments as it pertains to the pressor reflex evoked by static contraction and stretch of skeletal muscle. In this preparation, cats were anesthetized and the afferent fibers mediating the pressor reflex entered the spinal cord via the L7 dorsal root. Blockade of dorsal horn NMDA receptors at L6 and L7 attenuated the pressor reflex evoked by static contraction and muscle stretch. However, NMDA block in the L6 dorsal horn alone failed to alter the peak increase in MAP produced by static contraction and muscle stretch, but the initial pressor response evoked by static contraction was attenuated. These data support the hypothesis that the pressor reflex is partially mediated by activation of NMDA receptors in the dorsal horn, and this occurs at multiple spinal segments. Further, these data suggest that activation of NMDA receptors plays an important role in initiating the rise in arterial pressure produced by static contraction of skeletal muscle.
本研究的目的是探讨相邻脊髓节段背角中N-甲基-D-天冬氨酸（NMDA）受体阻断对骨骼肌静态收缩和拉伸所诱发的升压反射的影响。在此实验准备中，猫被麻醉，介导升压反射的传入纤维经L7背根进入脊髓。L6和L7节段背角的NMDA受体阻断减弱了静态收缩和肌肉拉伸所诱发的升压反射。然而，单独阻断L6背角的NMDA受体未能改变静态收缩和肌肉拉伸所产生的平均动脉压（MAP）峰值升高，但静态收缩所诱发的初始升压反应减弱。这些数据支持以下假说：升压反射部分由背角中NMDA受体的激活介导，且这种情况发生在多个脊髓节段。此外，这些数据表明NMDA受体的激活在引发骨骼肌静态收缩所产生的动脉血压升高方面起重要作用。
