Martin W J, Tsou K, Walker J M
Department of Psychology, Brown University, Providence, RI 02912, USA.
Neurosci Lett. 1998 Feb 6;242(1):33-6. doi: 10.1016/s0304-3940(98)00044-5.
Systemic administration of cannabinoids produce profound antinociception in rodents. The purpose of this study was to examine the contribution of the rostral ventromedial medulla (RVM) to cannabinoid-mediated inhibition of the tail-flick reflex. Rats received direct injections of two selective cannabinoid agonists, WIN55,212-2 and HU210, into the RVM. Both compounds significantly elevated tail-flick latencies by over 50%. WIN55,212-3, the inactive enantiomer, was without effect. Furthermore, co-administration of the selective cannabinoid receptor antagonist, SR141716A greatly attenuated the antinociception produced by HU210. Finally, injections of WIN55,212-2 outside the region of the RVM did not affect tail-flick latencies. These results demonstrate that the cannabinoid receptor system participates in the descending control of nociception and raise the possibility that actions of endogenous cannabinoids in the RVM may modulate nociceptive responsiveness.
对啮齿动物进行大麻素全身给药会产生显著的抗伤害感受作用。本研究的目的是研究延髓头端腹内侧区（RVM）在大麻素介导的甩尾反射抑制中的作用。给大鼠直接向RVM注射两种选择性大麻素激动剂WIN55,212-2和HU210。两种化合物均使甩尾潜伏期显著延长超过50%。无活性对映体WIN55,212-3则无此作用。此外，选择性大麻素受体拮抗剂SR141716A的共同给药大大减弱了HU210产生的抗伤害感受作用。最后，在RVM区域外注射WIN55,212-2不影响甩尾潜伏期。这些结果表明，大麻素受体系统参与伤害感受的下行控制，并增加了内源性大麻素在RVM中的作用可能调节伤害感受反应性的可能性。
