en Behavioral Neuroscience Behavioral Neuroscience Original Original <div style="text-align: justify;"><strong>Introduction: </strong>The current study aimed at investigating the role of Nitric Oxide (NO) in the maintenance of anxiety and depression induced by stress in male Wistar rats using intra-Basolateral Amygdala (BLA) injection of NO precursor, L-arginine, Nitric Oxide Synthase (NOS) inhibitor, and L-NAME.&nbsp;<br> <strong>Methods:</strong> Two 23-gauge stainless steel cannulas were placed in the BLA, stereotaxically. Seven days later, animals experienced electro foot shock stress based on the following protocol: animals experienced four sessions of stress for 60 minutes in four consecutive days. Five minutes before each stress session, the animals received different doses of L-arginine or L-NAME (1, 5 and, 10 &mu;g/rat) or saline (0.5 &mu;L/rat) intra-BLA. Six days after the stress termination, animals were tested for maintenance of anxiety-like behavior (elevated plus maze; EPM) and eight days after the stress they were examined for depression (forced swimming test; FST).<br> <strong>Results:</strong> Stress reduced the time and number of open arms and decreased motor activity on EPM. Stress-induced anxiety was inhibited by L-arginine and L-NAME (1, 5, and 10 &micro;g/rat). L-Arginine and L-NAME induced anxiety in non-stressed rats. Stress also increased the immobility time in animals in FST paradigm. Interestingly, both L-arginine and L-NAME, in all doses reduced the stress effect.<br> <strong>Conclusion: </strong>BLA nitric oxide may play a pivotal role in anxiety and depression induced by stress in rats. Since the effects of both L-arginine and L-NAME were similar, NO might have a modulatory role in the BLA.&nbsp;</div> Anxiety, Basolateral Amygdala, Depression, Nitric Oxide, L-Arginine, Stress 13 22 http://bcn.iums.ac.ir/browse.php?a_code=A-10-15-10&slc_lang=en&sid=1 Esmaeil Nikkar enikkar@yahoo.com 13700319475328460019980 13700319475328460019980 No Department of Physiology and Biophysics, School of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran. Hassan Ghoshooni ghoshooni287@gmail.com 13700319475328460019981 13700319475328460019981 No Department of Physiology and Biophysics, School of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran. Mohammad Mahdi Hadipour mm.hadipour@gmail.com 13700319475328460019982 13700319475328460019982 No Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Hedayat Sahraei h.sahraei@bmsu.ac.ir 13700319475328460019983 13700319475328460019983 Yes Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.