Chen X H, Geller E B, Adler M W
Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Neuropharmacology. 1998 Jun;37(6):751-7. doi: 10.1016/s0028-3908(98)00028-8.
Cholecystokinin octapeptide (CCK-8) (0.25-2.0 ng), the CCK(A) receptor antagonist L-364,718 (60-100 ng) or the CCK(B) receptor antagonist L-365,260 (0.3125-1.25 ng) was administered into the periaqueductal grey (PAG) of male SD rats. The antinociceptive effect induced by electroacupuncture (EA) stimulation of different frequencies was then measured by the cold water tail-flick (CWT) test. The results showed that (1) microinjection of CCK-8 into the PAG can significantly block the antinociceptive effect induced by all frequencies of EA stimulation. The effectiveness of the blockade was 100 > 2 Hz. In addition, CCK-8 blocks the antinociception seen following termination of the electrical stimulation at 100 Hz; (2) microinjection of L-365,260 (1.25 ng) into the PAG significantly increased the 100 Hz EA antinociceptive effect but not the 2 Hz EA antinociceptive effect and microinjection of L-364,718 into PAG did not affect either 2 or 100 Hz EA antinociception. These results demonstrate that CCK-8 in the PAG can antagonize the antinociceptive effect induced by EA stimulation, and the CCK effect is likely to be mediated by the CCK(B) receptor, but not the CCK(A) receptor.
将八肽胆囊收缩素（CCK - 8）（0.25 - 2.0纳克）、CCK（A）受体拮抗剂L - 364,718（60 - 100纳克）或CCK（B）受体拮抗剂L - 365,260（0.3125 - 1.25纳克）注入雄性SD大鼠的导水管周围灰质（PAG）。然后通过冷水甩尾（CWT）试验测量不同频率电针（EA）刺激诱导的抗伤害感受作用。结果表明：（1）向PAG微量注射CCK - 8可显著阻断所有频率EA刺激诱导的抗伤害感受作用。阻断效果为100 > 2赫兹。此外，CCK - 8可阻断100赫兹电刺激终止后出现的抗伤害感受；（2）向PAG微量注射L - 365,260（1.25纳克）可显著增强100赫兹EA的抗伤害感受作用，但不影响2赫兹EA的抗伤害感受作用，而向PAG微量注射L - 364,718对2赫兹或100赫兹EA的抗伤害感受均无影响。这些结果表明，PAG中的CCK - 8可拮抗EA刺激诱导的抗伤害感受作用，且CCK的作用可能由CCK（B）受体介导，而非CCK（A）受体。
