Mickley G Andrew, Remmers-Roeber Dawn R, Dengler Christine M, McMullen Colleen A, Kenmuir Cynthia L, Girdler Benjamin, Crouse Carrie, Walker Crystal
Department of Psychology and the Neuroscience Program, Carnegie Hall, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA.
J Neurosci Methods. 2002 Mar 30;115(1):85-92. doi: 10.1016/s0165-0270(02)00005-5.
When behavioral pharmacologists/toxicologists study conditioned taste aversions (CTAs), or other conditioned responses, as a means to investigate the effects of various drugs or toxins on a learned response, failure to discover a CTA is frequently attributed to the treatment's influence on the associative process. This kind of analysis may fail to identify drug-induced sensory changes that may influence conditioned stimulus (CS) or unconditioned stimulus (US) saliency. The current paper outlines a simple method by which a drug's influence on CS or US sensation may be determined. Further, illustrative data are provided regarding how N-methyl-D-aspartate (NMDA) receptor blockade modulates taste and the sensation of malaise. Ketamine (an NMDA receptor antagonist) has been reported to block CTAs in both neonatal and adult rats. The current experiments evaluated ketamine's ability to modulate the taste of a frequently employed CS (saccharin HCl=SAC) or the aversive aspects of a common US (Lithium Chloride=LiCl). Rats normally exhibit a preference for 0.3% SAC over 0.6% SAC and will suppress consumption of these liquids following an injection of LiCl. We report that ketamine did not markedly antagonize these consummatory patterns nor did it disrupt spontaneous locomotor movements. Taken together, these findings point to ketamine's limited ability to change the sensory capacities required for CTA formation. Investigators interested in determining the underlying causes of drug-induced CTA blockade may choose to employ paradigms similar to the one used here.
当行为药理学家/毒理学家研究条件性味觉厌恶（CTA）或其他条件性反应，以此作为研究各种药物或毒素对习得反应影响的一种手段时，未能发现CTA常常被归因于该处理对联想过程的影响。这种分析可能无法识别出可能影响条件刺激（CS）或非条件刺激（US）显著性的药物诱导的感觉变化。本文概述了一种简单的方法，通过该方法可以确定药物对CS或US感觉的影响。此外，还提供了关于N-甲基-D-天冬氨酸（NMDA）受体阻断如何调节味觉和不适感觉的说明性数据。据报道，氯胺酮（一种NMDA受体拮抗剂）在新生和成年大鼠中均可阻断CTA。当前的实验评估了氯胺酮调节常用CS（糖精盐酸盐=SAC）的味觉或常见US（氯化锂=LiCl）的厌恶方面的能力。大鼠通常偏好0.3%的SAC而非0.6%的SAC，并且在注射LiCl后会抑制这些液体的消耗。我们报告称，氯胺酮并未明显拮抗这些进食模式，也未扰乱自发运动。综上所述，这些发现表明氯胺酮改变CTA形成所需感觉能力的能力有限。有兴趣确定药物诱导CTA阻断潜在原因的研究人员可能会选择采用类似于此处使用的范式。
