Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
J Psychopharmacol. 2012 Apr;26(4):564-74. doi: 10.1177/0269881111405556. Epub 2011 May 31.
Involvement of the dopamine receptors in the basolateral amygdala (BLA) in the effects of histamine on anxiety-like behaviors of the elevated plus maze in male Wistar rats was investigated. The results showed that bilateral intra-BLA injections of histamine (2.5, 5 and 7.5 µg/rat) induced an anxiogenic-like effect, revealed by decreases in percentage of open arm time (%OAT) and open arm entries (%OAE). Intra-BLA administration of dopamine D1 receptor agonist, SKF38393 (0.25 µg/rat), and dopamine D2 receptor agonist, quinpirole (0.03 and 0.05 µg/rat), decreased %OAT but not %OAE. Conversely, intra-BLA administration of dopamine D1 receptor antagonist, SCH23390 (0.5 and 1 µg/rat), and dopamine D2 receptor antagonist, sulpiride (0.3 and 0.5 µg/rat), increased %OAT and %OAE, suggesting an anxiolytic-like effect for both drugs. Interestingly, co-administration of a silent dose of SCH23390 or sulpiride prevented anxiogenic-like effects of SKF38393 and quinpirole, respectively. Conjoint administration of a sub-effective dose of SKF38393 (0.125 µg/rat) or quinpirole (0.01 µg/rat) along with lower doses of histamine (1 and 2.5 µg/rat) induced anxiolytic-like effects. On the other hand, intra-BLA pretreatment with a silent dose of SCH23390 (0.25 µg/rat) or sulpiride (0.1 µg/rat) prevented the anxiogenic-like effect of higher doses of histamine (5 and 7.5 µg/rat). No significant change was observed in total closed arm entries, as an index for motor activity of the animals. It can be concluded that the dopamine D1 and D2 receptors in the BLA may be involved in the anxiogenic-like effects induced by histamine.
研究了外侧杏仁核（BLA）中的多巴胺受体在组胺对雄性 Wistar 大鼠高架十字迷宫焦虑样行为的影响中的作用。结果表明，双侧 BLA 内注射组胺（2.5、5 和 7.5μg/只大鼠）可诱导焦虑样效应，表现为开放臂时间百分比（%OAT）和开放臂进入次数百分比（%OAE）减少。BLA 内给予多巴胺 D1 受体激动剂 SKF38393（0.25μg/只大鼠）和多巴胺 D2 受体激动剂喹吡罗（0.03 和 0.05μg/只大鼠）可降低%OAT，但不降低%OAE。相反，BLA 内给予多巴胺 D1 受体拮抗剂 SCH23390（0.5 和 1μg/只大鼠）和多巴胺 D2 受体拮抗剂舒必利（0.3 和 0.5μg/只大鼠）可增加%OAT 和%OAE，表明两种药物均具有抗焦虑样作用。有趣的是，给予沉默剂量的 SCH23390 或舒必利可分别预防 SKF38393 和喹吡罗的焦虑样作用。联合给予亚有效剂量的 SKF38393（0.125μg/只大鼠）或喹吡罗（0.01μg/只大鼠）以及较低剂量的组胺（1 和 2.5μg/只大鼠）可诱导抗焦虑样作用。另一方面，BLA 内给予沉默剂量的 SCH23390（0.25μg/只大鼠）或舒必利（0.1μg/只大鼠）可预防较高剂量的组胺（5 和 7.5μg/只大鼠）引起的焦虑样作用。动物的运动活动指标总封闭臂进入次数没有明显变化。可以得出结论，BLA 中的多巴胺 D1 和 D2 受体可能参与了组胺引起的焦虑样效应。
