Electrophysiological Studies on the Mechanism of Neuroleptanalgesia in the Central Nervous System Part III

Abstract

In an attempt to clarify the mechanism of neuroleptanalgesia in the central nervous system, the following series of experiments were performed using droperidol and fentanyl citrate. The subjects for the experiments were rabbits.
1) Nine components (PPR₁, PPR₂, PPR₃, PPR₄, PPR₅, PPR₆, PPR₇, PPR₈ and PPR₉ )in PPR were observed in response to the photic stimulation through monopolar lead.
2) It was found that the PPR components were inhibited by the administratio n of droperidol or fentanyl citrate. But when droperidol and fentanyl citrate were simultaneously administered in the ratio of 50: 1, only PPR₆ was found to increase.
3) It was found that the components of PPR except PPR₆ were less inhibited following destruction of the VA and the CM when droperidol and fentanyl citrate were administered simultaneously. The PPR₆, however, was found also inhibited.
4) The results of the above mentioned series of e xperiments may lead us to the conclusion that the inhibitory effect becomes stronger for the components of PPR when droperidol and fentanyl citrate are administered simultaneously, and that this inhibitory effect is related to the VA or the CM, the thalamic nuclei which belong to the diffuse thalamocortical projection system.