Segal D S, Browne R G, Bloom F, Ling N, Guillemin R
Science. 1977 Oct 28;198(4315):411-4. doi: 10.1126/science.910136.
The opiatelike neuropeptide beta-endorphin produces a spectrum of effects that contrasts with that induced by the neuroleptic haloperidol. Rats injected intraventricularly or directly into the periaqueductal gray with beta-endorphin (0.5 to 50 micrograms) exhibited rigid immobility accompanied by the loss of righting reflex; the period of rigidity was preceded or followed (depending upon dose) by a state of hyperactivity. In contrast, no dose of haloperidol tested (0.5 to 12 milligrams per kilogram) produced rigidity, loss of righting reflex, or behavioral excitation. Furthermore, whereas animals injected with haloperidol remained stationary on a vertical grid, rats injected with beta-endorphin typically slid off the grid. Moreover, combined beta-endorphin and haloperidol treatment produced flaccidity in most animals. These results do not support the contention that this opiatelike peptide may be a naturally occurring neuroleptic.
类阿片神经肽β-内啡肽产生的一系列效应与抗精神病药物氟哌啶醇所诱导的效应形成对比。向大鼠脑室内或直接向中脑导水管周围灰质注射β-内啡肽（0.5至50微克）后，大鼠会出现强直不动，并伴有翻正反射丧失；强直期之前或之后（取决于剂量）会出现多动状态。相比之下，所测试的任何剂量的氟哌啶醇（每千克0.5至12毫克）均未产生强直、翻正反射丧失或行为兴奋。此外，注射氟哌啶醇的动物在垂直网格上保持静止，而注射β-内啡肽的大鼠通常会从网格上滑落。而且，β-内啡肽和氟哌啶醇联合治疗在大多数动物中产生了松弛状态。这些结果不支持这种类阿片肽可能是天然存在的抗精神病药物这一论点。
