Vasquez E, Vanegas H
Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas.
Brain Res. 2000 Jan 31;854(1-2):249-52. doi: 10.1016/s0006-8993(99)02303-3.
Microinjection of non-opioid analgesics, such as dipyrone (DIP), into the periaqueductal gray matter (PAG) in rats causes an inhibition of nociceptive circuits in the spinal cord. We have herein investigated whether this effect is mediated by opioidergic mechanisms in the rostral ventromedial medulla (RVM), which is an important relay between the PAG and the spinal cord. The responses of spinal wide-dynamic-range neurons to noxious stimulation of their receptive field (RF) were inhibited by microinjection of DIP (100 microg/0.5 microl) into PAG. Subsequent microinjection of naloxone (NAL; 0.5 microg/0.5 microl) into RVM reversed this inhibition. The present and previous results suggest that non-opioid analgesics, as well as opiates, inhibit nociception by activating descending opioidergic mechanisms in PAG and RVM.
向大鼠中脑导水管周围灰质（PAG）微量注射非阿片类镇痛药，如安乃近（DIP），可抑制脊髓中的伤害性感受回路。我们在此研究了这种作用是否由延髓头端腹内侧区（RVM）中的阿片能机制介导，RVM是PAG与脊髓之间的重要中继站。向PAG微量注射DIP（100微克/0.5微升）可抑制脊髓广动力范围神经元对其感受野（RF）的有害刺激的反应。随后向RVM微量注射纳洛酮（NAL；0.5微克/0.5微升）可逆转这种抑制作用。目前和先前的结果表明，非阿片类镇痛药以及阿片类药物通过激活PAG和RVM中的下行阿片能机制来抑制伤害感受。
