Lim A T, Funder J W
Neuroendocrinology. 1983;36(3):225-34. doi: 10.1159/000123460.
Immunoreactive beta-endorphin (ir-beta EP) levels were determined in plasma, anterior pituitary (AP), neuro-intermediate lobe (N-IL) and hypothalamus (HT) of intact rats and adrenalectomized rats subjected to swimming stress. In intact rats, plasma ir-beta EP was elevated fourfold, and ir-beta EP levels in AP and N-IL significantly reduced after 30 min swimming; in contrast, HT ir-beta EP in these animals was not affected. In adrenalectomized animals, similar but even more marked changes were found in plasma and tissue ir-beta EP following stress. The effect of diurnal variation, morphine and naloxone on stress-induced changes in tissue ir-beta EP was also examined; in addition, the influence of acute and chronic treatment of adrenalectomized animals with dexamethasone or deoxycorticosterone was explored. Plasma ir-beta EP of rats swum in the afternoon was significantly higher than of those swum in the morning; no differences were detected in AP, N-IL or HT ir-beta EP. Acute morphine administration (10 mg/kg) did not affect levels of ir-beta EP in any tissue, baseline or post-stress; however, naloxone (10 mg/kg) consistently and significantly prevented the reduction in N-IL ir-beta EP otherwise found following prolonged stress. Both acute and chronic dexamethasone (2 and 20 micrograms) attenuated the stress-induced changes found in AP and plasma ir-beta EP in a dose-related manner; equivalent effects, however, were not seen in deoxycorticosterone (20, 200 micrograms) treated animals. In contrast, the stress-induced reduction found in N-IL ir-beta EP was influenced neither by acute nor chronic treatment with dexamethasone or deoxycorticosterone. These results suggest that changes found in AP and plasma ir-beta EP after swimming stress are glucocorticoid-sensitive, but do not involve pathways including opiate receptors; in contrast, though baseline levels of N-IL ir-beta EP are mineralocorticoid-sensitive, the changes after swimming stress are steroid-independent and involve the action of endogenous opioids.
在完整大鼠和经游泳应激的肾上腺切除大鼠的血浆、垂体前叶（AP）、神经中间叶（N-IL）和下丘脑（HT）中测定免疫反应性β-内啡肽（ir-βEP）水平。在完整大鼠中，游泳30分钟后血浆ir-βEP升高四倍，AP和N-IL中的ir-βEP水平显著降低；相比之下，这些动物的HT ir-βEP不受影响。在肾上腺切除的动物中，应激后血浆和组织ir-βEP出现类似但更明显的变化。还研究了昼夜变化、吗啡和纳洛酮对应激诱导的组织ir-βEP变化的影响；此外，还探讨了用 dexamethasone 或脱氧皮质酮对肾上腺切除动物进行急性和慢性治疗的影响。下午游泳的大鼠的血浆ir-βEP显著高于上午游泳的大鼠；在AP、N-IL或HT ir-βEP中未检测到差异。急性给予吗啡（10mg/kg）不影响任何组织（基线或应激后）中ir-βEP的水平；然而，纳洛酮（10mg/kg）持续且显著地阻止了长时间应激后N-IL ir-βEP的降低。急性和慢性dexamethasone（2和20微克）均以剂量相关的方式减弱了在AP和血浆ir-βEP中发现的应激诱导变化；然而，在脱氧皮质酮（20、200微克）处理的动物中未观察到等效作用。相比之下，N-IL ir-βEP中发现的应激诱导降低既不受dexamethasone也不受脱氧皮质酮的急性或慢性治疗影响。这些结果表明，游泳应激后在AP和血浆ir-βEP中发现的变化对糖皮质激素敏感，但不涉及包括阿片受体的途径；相比之下，尽管N-IL ir-βEP的基线水平对盐皮质激素敏感，但游泳应激后的变化与类固醇无关，且涉及内源性阿片类物质的作用。
