Fluck E, Hogg S, Jones R B, Bourne R, File S E
Psychopharmacology Research Unit, UMDS Division of Pharmacology, Guys Hospital, London, UK.
Pharmacol Biochem Behav. 1997 Sep;58(1):269-74. doi: 10.1016/s0091-3057(96)00554-0.
Changes in the GABA-benzodiazepine system were investigated following regular handling of male chicks. Compared with handling-naive chicks, those exposed to 10 days of gentle handling required a larger number of inductions and had a lower duration of tonic immobility. Corresponding biochemical changes occurred, with handling-habituated chicks having a significantly lower basal [14C]GABA release from archistriatal slices and a reduction in the Bmax of [3H]muscimol binding in the forebrain. Benzodiazepine binding in the archistriatum was investigated using in vitro quantitative receptor autoradiography. Binding was localised in the anterior, mediale, dorsalis, and ventralis intermedium nuclei of the archistriatum, and there was significantly more binding in the anterior and ventralis intermedium/mediale archistriatum nuclei than in the dorsalis intermedium archistriatum nuclei. Benzodiazepine binding was not altered after handling in any of the investigated nuclei of the archistriatum. The results suggest that whereas several days of gentle handling in chicks leads to a decrease in forebrain GABAA receptors and a decrease in GABA release from the archistriatum, there are no accompanying changes in benzodiazepine receptors. Regular handling exerts a specific effect on chicks: it reduces their fear or human beings but not that of novel places or objects. It is possible that the pattern of biochemical changes observed in the present study may be specifically associated with this particular behavioural modification rather than with a change in general fearfulness.
在对雄性雏鸡进行定期处理后，研究了γ-氨基丁酸-苯二氮䓬系统的变化。与未处理过的雏鸡相比，接受10天轻柔处理的雏鸡需要更多次数的诱导，且强直性静止的持续时间更短。相应的生化变化也出现了，习惯处理的雏鸡从旧纹状体切片中的基础[14C]γ-氨基丁酸释放量显著降低，前脑[3H]蝇蕈醇结合的Bmax也降低。使用体外定量受体放射自显影法研究了旧纹状体中的苯二氮䓬结合情况。结合定位于旧纹状体的前、内侧、背侧和腹侧中间核，前侧和腹侧中间/内侧旧纹状体核中的结合明显多于背侧中间旧纹状体核。在旧纹状体的任何研究核中，处理后苯二氮䓬结合均未改变。结果表明，雏鸡经过几天的轻柔处理后，前脑γ-氨基丁酸A受体减少，旧纹状体γ-氨基丁酸释放减少，但苯二氮䓬受体没有相应变化。定期处理对雏鸡有特定影响：它会降低雏鸡对人的恐惧，但不会降低对新地方或新物体的恐惧。本研究中观察到的生化变化模式可能与这种特定的行为改变有特定关联，而不是与一般恐惧程度的变化有关。
