Broersen L M, Heinsbroek R P, de Bruin J P, Olivier B
Graduate School Neurosciences Amsterdam, Netherlands Institute for Brain Research, The Netherlands.
Biol Psychiatry. 1996 Dec 1;40(11):1083-90. doi: 10.1016/S0006-3223(95)00595-1.
The involvement of the dopamine (DA) innervation of the medial prefrontal cortex (PFC) in attention was studied in a latent inhibition (LI) paradigm in rats. LI becomes evident by a retardation of conditioning to a stimulus after nonreinforced preexposure to that stimulus. LI is thought to reflect an animal's ability not to attend to irrelevant stimuli and is often used as an animal paradigm modeling schizophreniclike attentional deficits. In the present study the effects of bilateral infusions of the DA receptor agonist apomorphine (APO, 9.0 micrograms/side) and the DA receptor antagonist cis-flupenthixol (FLU, 12.0 micrograms/side) into the medial PFC on LI were assessed. Although in comparison with vehicle both APO and FLU infusions attenuated response suppression in nonpreexposed animals, the drugs differentially affected LI in preexposed animals. After infusions of APO animals failed to show conditioned suppression, whereas FLU-treated animals displayed as much suppression of responding as nonpreexposed animals. The abolition of LI induced by FLU infusions into the medial PFC suggests that prefrontal DA is involved in attentional processes in a way opposite to the established role of subcortical DA systems in these processes.
在大鼠的潜伏抑制（LI）范式中，研究了内侧前额叶皮质（PFC）的多巴胺（DA）神经支配在注意力方面的作用。在对某刺激进行无强化的预暴露后，对该刺激的条件反射延迟会使LI变得明显。LI被认为反映了动物不关注无关刺激的能力，并且常被用作模拟精神分裂症样注意力缺陷的动物范式。在本研究中，评估了向内侧PFC双侧注射DA受体激动剂阿扑吗啡（APO，9.0微克/侧）和DA受体拮抗剂顺式氟哌噻吨（FLU，12.0微克/侧）对LI的影响。尽管与溶剂对照相比，注射APO和FLU均减弱了未预暴露动物的反应抑制，但这两种药物对预暴露动物的LI有不同影响。注射APO后，动物未表现出条件性抑制，而接受FLU治疗的动物与未预暴露动物一样表现出对反应的抑制。向内侧PFC注射FLU导致LI消失，这表明前额叶DA以与皮质下DA系统在这些过程中既定作用相反的方式参与注意力过程。
