Intrathecal blockade of both NMDA and non-NMDA receptors attenuates the exercise pressor reflex in cats.
Intrathecal blockade of both NMDA and non-NMDA receptors attenuates the exercise pressor reflex in cats.
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鞘内阻断 NMDA 和非 NMDA 受体会减弱猫的运动升压反射。
DOI：
10.1152/jappl.1996.80.1.315
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Kaufman,MP
中科院分区：
文献类型：
--
作者：
Adreani,CM;Hill,JM;Kaufman,MP
在去大脑未麻醉的猫身上，我们测试了一种假说，即腰椎脊髓中的谷氨酸受体阻断减弱了由小腿三头肌静态收缩引起的平均动脉压、激发的每分钟通气量和肾交感神经活动(RSNA)的反射性增加。鞘内注射DL-2-氨基-5-磷酸丙戊酸阻断N-甲基-D-天冬氨酸(NMDA)受体对收缩的升压、呼吸和RSNA反应的初始时相无影响，但可减弱这些反应的第二时相。鞘内注射6-氰基-7-硝基-喹恶啉-2，3-二酮，随后阻断腰骶髓中的非NMDA受体，可减弱升压、RSNA和对收缩的呼吸反应以及这些反应的第二阶段。此外，阻断NMDA受体对肌腱拉伸的升压或RSNA反应没有影响，而非NMDA受体阻断则取消了这些反应。我们通过一系列实验证实了我们的结果与注射拮抗剂的顺序无关，在这些实验中，首先注射了非NMDA受体拮抗剂。我们的发现表明，非NMDA受体介导了升压、RSNA的第一和第二阶段的脊髓传递，以及对收缩和肌腱拉伸的呼吸反应。因此，背角中的非NMDA受体似乎参与了机械感受器和代谢物感受器输入的脊髓处理。我们的发现还表明，NMDA受体介导了加压第二阶段RSNA的脊髓传递和对收缩的呼吸反应，但不中介对肌腱拉伸的反应的脊髓传递。因此，后角的NMDA受体似乎参与了代谢物受体传入的脊髓处理。
In decerebrate unanesthetized cats we tested the hypothesis that glutamatergic-receptor blockade in the lumbosacral spinal cord attenuated the reflex increases in mean arterial pressure, inspired minute ventilation, and renal sympathetic nerve activity (RSNA) evoked by static contraction of the triceps surae muscles. Blockade of N-methyl-D-aspartate (NMDA) receptors by intrathecal injection of DL-2-amino-5-phosphonovaleric acid had no effect on the initial phase of the pressor, ventilatory, and RSNA responses to contraction but did attenuate the secondary phase of these responses. Subsequent blockade of non-NMDA receptors in the lumbosacral spinal cord by intrathecal injection of 6-cyano-7-nitroquinoxaline-2,3-dione attenuated both the initial phase of the pressor, RSNA, and ventilatory responses to contraction and the secondary phase of these responses. In addition, NMDA-receptor blockade had no effect on the pressor or RSNA responses to tendon stretch, whereas non-NMDA-receptor blockade abolished these responses. We confirmed that our results were not related to the order of the antagonists injected by performing a series of experiments in which a non-NMDA-receptor antagonist was injected first. Our findings suggest that non-NMDA receptors mediate the spinal transmission of the initial and secondary phases of the pressor, RSNA, and ventilatory responses to contraction and tendon stretch. Therefore, non-NMDA receptors in the dorsal horn appear to be involved in the spinal processing of input from mechanoreceptors and metaboreceptors. Our findings also suggest that NMDA receptors mediate the spinal transmission of the secondary phase of the pressor, RSNA, and ventilatory responses to contraction but do not mediate the spinal transmission of the responses to tendon stretch. Therefore, NMDA receptors in the dorsal horn appear to be involved in the spinal processing of input from metaboreceptors.