Silva M, Nogueira P J, Tomaz C
Laboratory of Psychobiology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil.
Behav Brain Res. 1993 Jul 30;56(1):101-6. doi: 10.1016/0166-4328(93)90026-m.
The present study investigated the effects of post-trial systemic injections of the neurokinin substance P (SP) on inhibitory avoidance learning in rats treated with naloxone before conditioning and/or test trials. Rats were trained in a step-down or uphill inhibitory avoidance task and tested 24 h later. The animals received, 30 min before training and/or testing an i.p. injection of saline or naloxone (Nx) at doses of 0.5; 1.0; 5.0 or 50 mg/kg. Immediately after training they were administered SP 50 micrograms/kg or vehicle. Animals that received Nx both before conditioning and test trials (5.0 and 50 mg/kg), in combination with SP, showed better test performance for the uphill and step-down avoidance then those treated only with SP. Nx administered only before training (5.0 and 50 mg/kg) or before test (0.5 to 50 mg/kg) reduced the effects of SP. These data are discussed in terms of the possibility that Nx produces a state-dependent learning when combined with SP.
本研究调查了在条件反射训练前和/或测试试验前用纳洛酮处理的大鼠中，试验后系统性注射神经激肽P物质（SP）对抑制性回避学习的影响。大鼠接受了一步下跳或上坡抑制性回避任务训练，并在24小时后进行测试。在训练和/或测试前30分钟，动物接受腹腔注射生理盐水或剂量为0.5、1.0、5.0或50mg/kg的纳洛酮（Nx）。训练后立即给它们注射50微克/千克的SP或赋形剂。在条件反射训练和测试试验前都接受Nx（5.0和50mg/kg）并联合SP的动物，在上坡和一步下跳回避测试中的表现比仅接受SP处理的动物更好。仅在训练前（5.0和50mg/kg）或测试前（0.5至50mg/kg）给予Nx会降低SP的作用。根据Nx与SP联合使用时产生状态依赖性学习的可能性对这些数据进行了讨论。
