Panksepp J, Bean N J, Bishop P, Vilberg T, Sahley T L
Pharmacol Biochem Behav. 1980 Nov;13(5):673-83. doi: 10.1016/0091-3057(80)90011-8.
When young animals are separated from their normal social environment in groups they distress vocalize (DV) less than when isolated alone. Opioid blockade with naloxone (1 mg/kg peripherally, and 1 microgram centrally) increased crying more in group tested chicks than individually tested ones. The serotonin receptor blocking agent methysergide and the cholinergic blocking agent atropine sulfate produced similar effects. The testing of birds in mirrored environments also produced a reduction of DV's, and all three receptor blocking agents augmented DV's more in mirrored environments than in mirrorless ones. However, in studies evaluating changes in this comfort response by facilitation of opiate, serotonin (5 HT), and acetylcholine (ACh) activity (with morphine, quipazine and pilocarpine, respectively), only morphine was found to magnify the comforting effect of mirrors. The effects of naloxone on contact comfort, and the acquisition and expression of imprinting were further evaluated, and opioid blockade reduced all these measures of social comfort. It is concluded that endogenous opioid activity (and to a lesser extent, 5 HT and ACh) contribute to the comfort which animals derive from their social environment.
当幼小动物在群体中与正常社会环境分离时，它们发出的痛苦叫声（DV）比单独隔离时少。用纳洛酮（外周1毫克/千克，中枢1微克）进行阿片类药物阻断，在群体测试的雏鸡中比单独测试的雏鸡引起更多的鸣叫。5-羟色胺受体阻断剂麦角新碱和胆碱能阻断剂硫酸阿托品产生了类似的效果。在有镜子的环境中对鸟类进行测试也会使DV减少，并且所有三种受体阻断剂在有镜子的环境中比在无镜子的环境中增加的DV更多。然而，在通过促进阿片类、5-羟色胺（5-HT）和乙酰胆碱（ACh）活性（分别用吗啡、喹哌嗪和毛果芸香碱）来评估这种舒适反应变化的研究中，仅发现吗啡能增强镜子的安慰效果。进一步评估了纳洛酮对接触安慰以及印记形成的获得和表达的影响，阿片类药物阻断降低了所有这些社会舒适的指标。得出的结论是，内源性阿片类活性（以及程度较轻的5-HT和ACh）有助于动物从其社会环境中获得的舒适感。
