The effects of peptide ACTH4-7-PGP (Semax) were studied in 12 min after its intraperitoneal (in doses of 5, 15, 50, 150, and 450 μg/kg) or intracerebroventricular (in doses of 16, 40, and 400 pg) administration to rats with different types of pain and pain-induced behavior. It was found that the peptide increased pain sensitivity and induced avoidance behavior during thermal stimulation ("hot plate" test), but had an analgesic effect (more pronounced after central administration) and weakened emotional-affective behavior in electrocutaneous stimulation of the paws (foot-shock model) and tail in rats. It was shown that changes in activity of supraspinal brain structures were of primary importance in the mechanism of action on the nociceptive process and the formation of behavior.

中文翻译：

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肽 ACTH4-7-PGP：对大鼠全身和中枢给药后各种类型的疼痛和疼痛诱导行为的影响

在腹膜内（剂量为 5、15、50、150 和 450 μg/kg）或脑室内（剂量为 16、40 和 400 pg) 对具有不同类型疼痛和疼痛诱发行为的大鼠给药。发现肽在热刺激（“热板”测试）期间增加疼痛敏感性并诱导回避行为，但具有镇痛作用（在中枢给药后更明显）并减弱爪子（足-休克模型）和大鼠的尾巴。结果表明，脊髓上脑结构活动的变化在伤害感受过程和行为形成的作用机制中是最重要的。