Matulewicz Paweł, Orzeł-Gryglewska Jolanta, Braszka Łukasz, Zawistowski Piotr, Jurkowlaniec Edyta
Department of Animal and Human Physiology, University of Gdańsk, 59 Wita Stwosza St., Gdańsk 80-308, Poland.
Department of Animal and Human Physiology, University of Gdańsk, 59 Wita Stwosza St., Gdańsk 80-308, Poland.
Neurosci Lett. 2015 Mar 4;589:132-7. doi: 10.1016/j.neulet.2015.01.049. Epub 2015 Jan 21.
The ventral tegmental area (VTA) is thought to be an important component in the mesocorticolimbic system involved in the regulation of theta rhythm in the hippocampus. In this study we investigate the effect of pharmacological inactivation (local procaine infusion) or activation (local amphetamine infusion) of the VTA on theta rhythm parameters during task specific behavior in fear conditioned, freely moving rats. Animals were implanted with bilateral recording electrodes into the dorsal hippocampus (CA1) and bilateral injection cannulas into the VTA. Behavioral activities and hippocampal local field potentials (LFP) were recorded throughout the experiment, in pre- and post-injection conditions. We found that intra-VTA injection of procaine temporarily suppressed fear conditioned avoidance response (escape from the foot-shock arena) and also influenced hippocampal theta rhythm parameters during immobility linked with arousal and/or attention. Procaine infusion decreased the signal power (Pmax) of theta rhythm during immobility behavior, in comparison to the control group (water infusion), whereas administration of amphetamine had no effect on the behavior and hippocampal LFP. Our results indicate that temporal inactivation of neuronal activity in the VTA affects hippocampal theta rhythm linked with attentional immobility and suppresses avoidance response in fear conditioned animals.
腹侧被盖区（VTA）被认为是中脑皮质边缘系统的一个重要组成部分，参与海马体中θ节律的调节。在本研究中，我们调查了在恐惧条件下自由活动的大鼠进行特定任务行为期间，VTA的药理学失活（局部注射普鲁卡因）或激活（局部注射苯丙胺）对θ节律参数的影响。将动物双侧记录电极植入背侧海马体（CA1），并将双侧注射套管植入VTA。在整个实验过程中，在注射前和注射后的条件下记录行为活动和海马体局部场电位（LFP）。我们发现，向VTA内注射普鲁卡因会暂时抑制恐惧条件下的回避反应（逃离足部电击区域），并且在与觉醒和/或注意力相关的静止期间也会影响海马体θ节律参数。与对照组（注射水）相比，注射普鲁卡因会降低静止行为期间θ节律的信号功率（Pmax），而注射苯丙胺对行为和海马体LFP没有影响。我们的结果表明，VTA中神经元活动的暂时失活会影响与注意力静止相关的海马体θ节律，并抑制恐惧条件下动物的回避反应。
