Shoemaker W J, Kehoe P
Department of Psychiatry, University of Connecticut Health Center, Farmington 06030-1410, USA.
Behav Neurosci. 1995 Feb;109(1):117-22. doi: 10.1037//0735-7044.109.1.117.
Young rat pups were isolated from their dams under different conditions. The endogenous opioid peptides were measured in brain regions after isolation. Because there is no uptake mechanism for peptides released at the synapse and because released peptide is rapidly degraded enzymatically, decreases in peptide levels over this time course can be interpreted as release from terminals. No change was observed in either peptide in the hypothalamus, septum, or amygdala after isolation compared with controls. Significant decreases were seen in the midbrain after isolation. A comparison of peptide levels and ultrasonic vocalizations in the pups isolated in familiar, novel, or control conditions was also performed. Enkephalin levels in the midbrain were decreased in familiar and novel conditions, but in the brainstem opioid peptides were decreased only in the familiar condition. The greater involvement of the opioid peptides in the pups isolated in familiar conditions may contribute to the ability of naltrexone to block vocalization.
将幼鼠在不同条件下与母鼠隔离。隔离后测量脑区中的内源性阿片肽。由于突触处释放的肽没有摄取机制，且释放的肽会迅速被酶降解，因此在这个时间过程中肽水平的下降可解释为从终末释放。与对照组相比，隔离后下丘脑、隔区或杏仁核中的两种肽均未观察到变化。隔离后中脑出现显著下降。还对在熟悉、新奇或对照条件下隔离的幼鼠的肽水平和超声波发声进行了比较。在熟悉和新奇条件下，中脑内脑啡肽水平下降，但在脑干中，仅在熟悉条件下阿片肽水平下降。在熟悉条件下隔离的幼鼠中，阿片肽的更大参与可能有助于纳曲酮阻断发声的能力。
