Institute of Biomedicine, Pharmacology, Biomedicum Helsinki, POB 63 (Haartmaninkatu 8), FI-00014 University of Helsinki, Finland.
Pharmacol Biochem Behav. 2012 Mar;101(1):115-24. doi: 10.1016/j.pbb.2011.12.011. Epub 2011 Dec 21.
The classical benzodiazepine diazepam (DZ) induces anxiolysis at low doses and sedation and hypnosis at higher doses. Different brain areas and neuronal populations most likely mediate these different behavioral effects. We used c-Fos immunohistochemistry as an indirect way to study neuronal activation or inhibition induced by DZ at anxiolytic and sedative doses (0.5 and 5mg/kg, respectively) in various brain areas involved in anxiety, arousal, sedation and addiction in C57BL/6J mice. We also focused on the two neuronal populations, orexinergic and dopaminergic neuronal populations, with the help of double-immunohistochemistry using c-Fos and orexin-A antibodies and c-Fos and tyrosine hydroxylase antibodies. We found that different brain areas of unhabituated mice reacted differently to the mild stress induced by vehicle injection. Also the response to anxiolytic or sedative doses of DZ differed between the areas, suggesting that distinct brain areas mediate the behavioral effects of low and high DZ doses. Our findings propose a role for inhibition of orexin neurons in the anxiolytic and sleep-promoting effects of DZ. In addition, the activation of central amygdala neurons by DZ treatment was associated with anxiolytic and sedative effects. On the other hand, the ventral hippocampus, basolateral amygdala, ventral tegmental area and prefrontal cortex were sensitive even to the mild injection stress, but not to the anxiolytic dose of DZ.
经典苯二氮䓬类药物地西泮（DZ）在低剂量时引起焦虑缓解，高剂量时引起镇静和催眠。不同的脑区和神经元群体可能介导这些不同的行为效应。我们使用 c-Fos 免疫组织化学作为一种间接方法，研究 DZ 在焦虑和镇静剂量（分别为 0.5 和 5mg/kg）下在参与焦虑、觉醒、镇静和成瘾的各种脑区中诱导的神经元激活或抑制，在 C57BL/6J 小鼠中。我们还借助 c-Fos 和食欲素-A 抗体和 c-Fos 和酪氨酸羟化酶抗体的双重免疫组织化学，重点研究了两种神经元群体，食欲素能和多巴胺能神经元群体。我们发现，未习惯的小鼠的不同脑区对载体注射引起的轻度应激反应不同。DZ 的抗焦虑或镇静剂量的反应也因区域而异，这表明不同的脑区介导低剂量和高剂量 DZ 的行为效应。我们的研究结果表明，抑制食欲素神经元在 DZ 的抗焦虑和促进睡眠作用中起作用。此外，DZ 处理激活中央杏仁核神经元与抗焦虑和镇静作用有关。另一方面，腹侧海马体、基底外侧杏仁核、腹侧被盖区和前额叶皮层即使对轻度注射应激也很敏感，但对 DZ 的抗焦虑剂量不敏感。
