Departamento de Psicofisiología, Facultad de Psicología, Universidad Nacional Autónoma de México, UNAM, Mexico.
Pharmacol Biochem Behav. 2013 Aug;109:44-9. doi: 10.1016/j.pbb.2013.05.003. Epub 2013 May 8.
Organisms are capable of making decisions based on their ability to discriminate between different stimuli. This principle is fundamental for the adaptation of organisms to their environment, by emitting appropriate behaviors based on a previously acquired discriminative process. The present study analyzed the participation of the peripheral nervous system, the M₁ muscarinic receptor subtype, as well as the contribution of the dorsolateral frontal cortex to discrimination process using scopolamine as discriminative stimulus. Male Wistar rats were trained to discriminate between scopolamine (1.0 mg/kg) and saline injections (i.p.) using a two-lever operant procedure. Once discrimination was acquired, generalization curves for scopolamine, methylscopolamine, pirenzepine, dorsolateral frontal cortex lesion and control conditions were obtained. Results showed that rats were able to discriminate and generalize its responses to different doses of scopolamine but not for methylscopolamine or pirenzepine, thus the data suggest that discriminative properties of scopolamine are processed in CNS and that the M₁ receptor does not participate in this process. Dorsolateral frontal cortex lesion did not produce any statistically significant difference in the generalization curve, which suggests that a system different from the dorsolateral prefrontal cortex may be responsible for the control of stimulus produced by scopolamine.
生物能够根据其区分不同刺激的能力做出决策。这一原则是生物适应环境的基础，通过基于先前获得的辨别过程发出适当的行为。本研究分析了外周神经系统、M₁毒蕈碱受体亚型以及背外侧额皮质在使用东莨菪碱作为辨别刺激时对辨别过程的参与。雄性 Wistar 大鼠通过双杠操作性程序训练，以区分东莨菪碱（1.0 mg/kg）和盐水注射（ip）。一旦获得辨别能力，就获得了东莨菪碱、甲基东莨菪碱、哌仑西平、背外侧额皮质损伤和对照条件的概括曲线。结果表明，大鼠能够辨别并概括其对不同剂量东莨菪碱的反应，但不能对甲基东莨菪碱或哌仑西平做出反应，因此数据表明，东莨菪碱的辨别特性是在中枢神经系统中处理的，M₁受体不参与这一过程。背外侧额皮质损伤对概括曲线没有产生任何统计学上的显著差异，这表明可能有一个不同于背外侧前额皮质的系统负责控制东莨菪碱产生的刺激。
