Jacquet Y F, Marks N
Science. 1976 Nov 5;194(4265):632-5. doi: 10.1126/science.185695.
Microinjection of the C-fragment (also called beta-endorphin), which is amino acid sequence 61-91 of the endogenous pituitary hormone, beta-lipotropin (beta-LPH), in the periaqueductal gray of the rat resulted in profound sedation and catalepsy, while microinjection of smaller fragments-that is, methionine-enkephalin [sequence beta-LPH-(61-65)] and its related pentapeptide, leucine enkephalin, and alpha-endorphin [sequence beta-LPH-(61-76)] resulted in attenuated forms of this behavior. This indicates that the C-fragment is an important neuromodulator of the central nervous system. The similarity of this behavior to that seen after systemic administration to experimental animals of exogenous neuroleptics suggests that a disturbance in the bioavailability of this neuropeptide to receptor sites in brain-perhaps due to lack of enzymatic cleavage from the circulating parent hormone, beta-lipotropin--may be an etiological factor in those psychopathological states for which the exogenous neuroleptics exert an ameliorative influence.
将内源性垂体激素β-促脂素（β-LPH）的氨基酸序列61-91的C片段（也称为β-内啡肽）微量注射到大鼠中脑导水管周围灰质中，会导致深度镇静和僵住症，而注射较小的片段，即甲硫氨酸脑啡肽[序列β-LPH-(61-65)]及其相关的五肽亮氨酸脑啡肽，以及α-内啡肽[序列β-LPH-(61-76)]，则会导致这种行为的减弱形式。这表明C片段是中枢神经系统的重要神经调节剂。这种行为与给实验动物全身施用外源性抗精神病药物后观察到的行为相似，这表明这种神经肽在脑内受体部位的生物利用度受到干扰——可能是由于缺乏从循环母体激素β-促脂素的酶促裂解——可能是那些外源性抗精神病药物能发挥改善作用的精神病理状态的一个病因因素。
