Wang C, Chakrabarti M K, Whitwam J G
Department of Anaesthesia, Hammersmith Hospital, Royal Postgraduate Medical School, London.
Br J Anaesth. 1993 Oct;71(4):528-33. doi: 10.1093/bja/71.4.528.
We observed that buprenorphine 20 micrograms kg-1 i.v. in dogs caused an initial significant reduction in both A delta and C fibre mediated somatosympathetic reflexes evoked by tibial and radial nerve stimulation, to approximately 75% and 70% of control values. Larger doses (up to 100 micrograms kg-1 i.v.) had progressively less effect and the mean responses were depressed to only approximately 65% and 55% of control, indicating a ceiling effect. Buprenorphine 450 micrograms intrathecally (i.t.) completely abolished tibial C fibre reflexes, but 20% of A delta responses could not be eliminated with doses up to 1050 micrograms i.t. Fentanyl 100 micrograms kg-1 i.v. or 150 micrograms i.t. after buprenorphine i.v. or i.t., respectively, had little additional effect. This study confirms the limited ceiling effect of buprenorphine on nociceptive reflexes when administered systemically, and provides evidence that when administered i.t. in sufficient doses it abolishes the C responses (lack of ceiling effect for C responses), but the A delta responses show a plateau or ceiling effect.
我们观察到，静脉注射20微克/千克丁丙诺啡可使犬的Aδ纤维和C纤维介导的由胫神经和桡神经刺激诱发的躯体交感反射最初显著降低，降至对照值的约75%和70%。更大剂量（静脉注射高达100微克/千克）的作用逐渐减弱，平均反应仅降至对照值的约65%和55%，表明存在封顶效应。鞘内注射450微克丁丙诺啡可完全消除胫神经C纤维反射，但鞘内注射高达1050微克的剂量也无法消除20%的Aδ反应。分别在静脉注射或鞘内注射丁丙诺啡后，静脉注射100微克/千克芬太尼或鞘内注射150微克芬太尼几乎没有额外作用。本研究证实了丁丙诺啡全身给药时对伤害性反射的封顶效应有限，并提供了证据表明，鞘内注射足够剂量时可消除C反应（C反应无封顶效应），但Aδ反应表现出平台效应或封顶效应。
