Toda T, Hayashi H
Department of Physiology, School of Dentistry, Tohoku University, Sendai, Japan.
Neurosci Lett. 1993 Aug 6;158(1):36-8. doi: 10.1016/0304-3940(93)90606-l.
The effects of local spinal applications of the substance P antagonist, CP-96,345, on the electrically-evoked discharges of nociceptive neurons were examined in the superficial spinal dorsal horn of adult rats anesthetized with sodium pentobarbital. Extracellular single-unit recordings were made from lumbar spinal dorsal horn neurons which were excited by noxious mechanical stimulation and had early and late discharges evoked by A- and C-fiber inputs, respectively, following transcutaneous electrical stimulation. CP-96,345 was applied directly onto the surface of the spinal cord close to the recording sites. A dose of 50 nmol of CP-96,345 drastically inhibited the late discharges of 80% of neurons, without affecting early discharges significantly. This study demonstrated the specific inhibitory effect of CP-96,345 on the late discharges of a restricted population of spinal dorsal horn neurons. These results illustrate the important role of substance P in nociceptive transmission mediated by primary afferent C-fibers in normal acute pain.
在戊巴比妥钠麻醉的成年大鼠的脊髓背角浅层，研究了局部脊髓应用P物质拮抗剂CP-96,345对伤害性神经元电诱发放电的影响。对腰段脊髓背角神经元进行细胞外单单位记录，这些神经元在经皮电刺激后，分别由A纤维和C纤维输入诱发早期和晚期放电，且对有害机械刺激有反应。将CP-96,345直接应用于靠近记录部位的脊髓表面。50 nmol剂量的CP-96,345能显著抑制80%神经元的晚期放电，而对早期放电无明显影响。本研究证明了CP-96,345对脊髓背角特定神经元群晚期放电的特异性抑制作用。这些结果说明了P物质在正常急性疼痛中由初级传入C纤维介导的伤害性传递中的重要作用。
