Neuroleptanalgesia(NLA)の中枢作用機序に関する生理学的研究(第2報)

抄録

In order to clarify the mechanism of neuroleptanalgesia (NLA) in the central nervous system, an experiment was performed using droperidol and fentanyl citrate. The subjects of the experiment were rabbits.
1) It wa s found that the average evoked potentials in the cerebral cortex through ATAC due to stimuli on the sciatic nerve were composed of three small negative responses (N₁, N₂, N₃), followed by a positive response (P) and four negative responses (N₄, Ne₅, Ne₆, N₇).
2) With regard to the average evoked potentials in the cerebral cortex, the late co mponents (N₄, N₅, N₆, N₇) exhibited stronger inhibitory effect than the early components (N₁, N₂, N₃) by droperidol.
3) As for fentanyl citrate: components N₁ and N₂ exhibited strong inhibitory effect, while components N₃, N₆ and N₇ exhibited weak inhibitory effect. When administered a proper dose, components P, N₄ and N₅ exhibited facilitatory effect.
4) When droperidol and fentanyl citrate were admin istered in combination at a ratio of 50: 1, for components N₁, N₂, P. N₄ and N₅, the functioning observed was identical to that observed when only fentanyl citrate was administered. However, the inhibitory effect became stronger for component N₃, and for components N₆ and N₇, the increased functioning during the proper dose was observed to become stronger.
5) Through stimulation of the sciatic nerve, three small negative responses (HN₁, HN₂, HN₃) were observed in the hippocampus, followed by three negative responses (HN₄, HN₅, HN₆).
6) With regard to the average evoked potentials in the hippocampus, both components HN₅and HN₆ exhibited stronger inhibitory effect than components HN₁, HN₂, HN₃ and HN₄.
7) As for fentanyl citrate: the early components HN₁, and HN₂, in addition to component HN6, exhibited strong inhibitory effect; while components HN₃, HN₄ and HN₅ exhib ited weak inhibitory effect.
8) When droperidol and fentanyl citrate were administered simultaneously, for components HN₁, HN₂ and HN₆, the functioning observed was identical to that observed w hen only fentanyl citrate was administered. However, for all of the other components especially for both components HN₄ and HN₅, the inhibitory effect was observed to become stronger. From the experimental results listed above, it has become clear that within the effects of NLA regarding the central nervous system, the analgesic action, in addition to functioning in the sensory afferent pathway, fulfills a substantial role functioning in the higher center in the hippocampus.