MORPHINE MICROINJECTED INTO THE PERIAQUEDUCTAL GRAY HAS DIFFERENTIAL-EFFECTS ON 3 CLASSES OF MEDULLARY NEURONS
MORPHINE MICROINJECTED INTO THE PERIAQUEDUCTAL GRAY HAS DIFFERENTIAL-EFFECTS ON 3 CLASSES OF MEDULLARY NEURONS
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DOI：
10.1016/0006-8993(86)90958-3
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发表时间：
1986-06-04
期刊：
影响因子：
2.9
通讯作者：
HEINRICHER, MM
中科院分区：
文献类型：
--
作者：
CHENG, ZF;FIELDS, HL;HEINRICHER, MM
在轻度麻醉大鼠中研究了中脑导水管周围灰质（PAG）中微量注射5-10 μ g吗啡对延髓头端腹侧区（RVM）神经元活动的影响。根据甩尾反射（TF）发生与神经元活动变化的关系，将RVM神经元分为3组：脱细胞、上细胞和中性细胞。关闭的细胞表现出一个突然的停顿和细胞的加速开始之前的TF的发生。在TF时，中性细胞放电没有变化。PAG内微量注射吗啡抑制TF对RVM内3组神经元自发活动的影响不同。在TF抑制之前，关闭细胞表现出自发活动的增加，而打开细胞表现出自发活动的减少。这些显微注射也减少了TF相关的反应关闭和上的细胞。对细胞活性的影响被全身给药的纳洛酮逆转，并且在未能阻断TF的显微注射后未观察到。PAG内微量注射吗啡后，中性细胞活性不变。这些结果支持了RVM中的关闭和开启细胞介导PAG中微量注射吗啡对脊髓伤害性反射的影响的假设。
The effects of microinjection of 5-10 .mu.g of morphine into the midbrain periaqueductal gray (PAG) on the activity of neurons in the rostral ventral medulla (RVM) were studied in lightly anesthetized rats. Based on the relationship between changes in neuronal activity and the occurrence of the tail-flick reflex (TF), RVM neurons were divided into 3 groups: off-cells, on-cells and neutral cells. The off-cells exhibited an abrupt pause and the on-cells an acceleration beginning just prior to the occurrence of the TF. Neutral cell firing did not change at the time of the TF. Microinjections of morphine into the PAG which inhibited the TF had differential effects on the spontaneous activity of the 3 groups of neurons in RVM. Off-cells showed an increase and on-cells a decrease in spontaneous activity which preceded the inhibition of the TF. These microinjections also reduced the TF-related responses of off- and on-cells. The effects on cell activity were reversed by systemically administered naloxone and were not seen following microinjections which failed to block the TF. Neutral cell activity was unchanged following microinjection of morphine into the PAG. These results support the hypothesis that off- and on-cells in the RVM mediate the effects of microinjection of morphine into the PAG on spinal nociceptive reflexes.