Knepper B R, Kurylo D D
Department of Psychology, Bowdoin College, Brunswick, ME 04011, USA.
Neuroscience. 1998 Apr;83(3):837-41. doi: 10.1016/s0306-4522(97)00457-0.
An investigation was made of the effects of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on the acquisition and retention of two operantly conditioned discrimination tasks. Twenty Long-Evans rats were conditioned to approach one of two spatial locations that was either held constant across trials (spatial task) or was associated with a visual cue (illuminated lamp) that was randomly assigned to one of the locations on each trial (cued task). Rats were assigned to one of two treatment groups in which they received intraperitoneal injections of either NG-nitro-L-arginine methyl ester or saline approximately 2 h before sessions on each day of training. Analysis was made of the trial-by-trial performance in order to identify the characteristics of learning under each condition. Assessment of learning acquisition was based on the number of trials required to reach a criterion of 80% correct responses, whereas retention was assessed by the number of trials to criterion on each day after the criterion was initially reached. Analysis indicated that treatment groups did not differ significantly on acquisition or retention of either the spatial or cued task. These results indicate that inhibition of nitric oxide synthase does not interfere with the learning or retention of basic operant tasks that involve simple spatial or visual analysis. Whereas results from biochemical and physiological investigations have suggested an impact of nitric oxide synthase on behavioural function, behavioural investigations indicate a limited impact of nitric oxide synthase inhibition on learning and memory. Although these results do not discount the role of nitric oxide synthase in a hippocampal mechanism, they illustrate that behavioural analysis should be made in the context of multiple interacting neural systems. Viewed with previous behavioural research on the effects of NG-nitro-L-arginine methyl ester, these results indicate that nitric oxide synthase inhibition results in impairment of certain forms of learning whereas other forms are preserved.
研究了一氧化氮合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）对两项操作性条件辨别任务的习得和保持的影响。20只Long-Evans大鼠被训练接近两个空间位置中的一个，该位置在各试验中保持不变（空间任务），或者与一个视觉线索（点亮的灯）相关联，该视觉线索在每次试验中随机分配到其中一个位置（线索任务）。大鼠被分配到两个治疗组之一，在训练的每一天，它们在训练前约2小时接受腹腔注射NG-硝基-L-精氨酸甲酯或生理盐水。对逐次试验的表现进行分析，以确定每种条件下学习的特征。学习习得的评估基于达到80%正确反应标准所需的试验次数，而保持则通过在最初达到标准后的每一天达到标准所需的试验次数来评估。分析表明，治疗组在空间任务或线索任务的习得或保持方面没有显著差异。这些结果表明，一氧化氮合酶的抑制不会干扰涉及简单空间或视觉分析的基本操作性任务的学习或保持。虽然生化和生理学研究的结果表明一氧化氮合酶对行为功能有影响，但行为学研究表明一氧化氮合酶抑制对学习和记忆的影响有限。虽然这些结果不排除一氧化氮合酶在海马机制中的作用，但它们表明行为分析应在多个相互作用的神经系统的背景下进行。结合先前关于NG-硝基-L-精氨酸甲酯作用的行为学研究来看，这些结果表明一氧化氮合酶抑制会导致某些形式的学习受损，而其他形式则得以保留。
