Lamont E W, Kokkinidis L
Department of Psychology, University of Saskatchewan, Saskatoon, SK, Canada.
Brain Res. 1998 Jun 8;795(1-2):128-36. doi: 10.1016/s0006-8993(98)00281-9.
Dopamine (DA) D1 receptors are distributed in the nucleus accumbens and the amygdala, two regions of the mesocorticolimbic DA system known to be activated by aversive environmental stimuli. The objective of the present study was to determine the contribution of D1 receptors in these brain regions to the expression of a fear-motivated behavior, notably, potentiated startle in rats. Injection of the DA D1 receptor antagonist SCH 23390 into the amygdala blocked the ability of a conditioned light stimulus previously paired with footshock to enhance acoustic startle amplitudes. Bilateral intracerebral administration of SCH 23390 into the nucleus accumbens had no effect on fear-potentiated startle. The observed opposing effects of amygdaloid DA D1 receptor antagonism on fear expression, along with earlier research demonstrating the involvement of ventral tegmental area (VTA) DA neurons on fear-potentiated startle, suggest a role for mesoamygdaloid activity in conditioned excitatory fear reactions.
多巴胺（DA）D1受体分布于伏隔核和杏仁核，这是中脑皮质边缘DA系统的两个区域，已知会被厌恶环境刺激激活。本研究的目的是确定这些脑区中的D1受体对恐惧驱动行为表达的作用，特别是大鼠的惊吓反应增强。向杏仁核注射DA D1受体拮抗剂SCH 23390可阻断先前与足部电击配对的条件性光刺激增强听觉惊吓幅度的能力。向伏隔核双侧脑内注射SCH 23390对恐惧增强的惊吓反应没有影响。杏仁核DA D1受体拮抗对恐惧表达的相反作用，以及早期研究表明腹侧被盖区（VTA）DA神经元参与恐惧增强的惊吓反应，提示中杏仁核活动在条件性兴奋性恐惧反应中起作用。
