Wiesenfeld-Hallin Z, Duranti R
Peptides. 1987 Jan-Feb;8(1):153-8. doi: 10.1016/0196-9781(87)90179-3.
The effect of intrathecal (IT) cholecystokinin (CCK), substance P (SP) and morphine (MO) on spinal cord excitability was studied in decerebrate, spinalized rats. CCK had a weaker facilitatory effect on the nociceptive flexion reflex than SP. The possible functional significance of the coexistence of CCK and SP in neurons projecting to the spinal cord was tested by coadministration of the two peptides. At the doses tested no synergistic interaction on the reflex was found with CCK and SP. IT MO caused a brief enhancement followed by a prolonged depression of the reflex. A high dose of CCK injected prior to MO increased the facilitatory effect and decreased the depressive effect of the opiate on the reflex. The effect of desulfated (D) CCK was similar to CCK but at a higher dose. Naloxone (NAL) had a similar effect as CCK when administered prior to MO. The MO-induced depression of the reflex was readily reversed by NAL, but not by CCK. The results indicate that CCK may prevent the inhibitory effect of MO on spinal cord excitability to nociceptive stimulation, but does not reverse it. CCK may alter the balance of excitation-inhibition between various types of dorsal horn interneurons that are involved in the transmission of nociceptive information.
在去大脑、脊髓横断的大鼠中研究了鞘内注射（IT）胆囊收缩素（CCK）、P物质（SP）和吗啡（MO）对脊髓兴奋性的影响。CCK对伤害性屈曲反射的易化作用比SP弱。通过同时给予这两种肽来测试CCK和SP在投射到脊髓的神经元中共存的可能功能意义。在所测试的剂量下，未发现CCK和SP对反射有协同相互作用。鞘内注射MO导致反射短暂增强，随后出现长时间抑制。在注射MO之前注射高剂量的CCK可增强阿片类药物对反射的易化作用并降低其抑制作用。去硫酸化（D）CCK的作用与CCK相似，但所需剂量更高。在注射MO之前给予纳洛酮（NAL），其作用与CCK相似。MO诱导的反射抑制很容易被NAL逆转，但不能被CCK逆转。结果表明，CCK可能会阻止MO对脊髓对伤害性刺激的兴奋性的抑制作用，但不能逆转这种作用。CCK可能会改变参与伤害性信息传递的各种类型背角中间神经元之间的兴奋-抑制平衡。
