effect of nitric oxide on basolateral amygdala on persistence of anxiety and depression in stressed male rats

Introduction: 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. methods: 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 μg/rat) or saline (0.5 μl/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). results: 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 μg/ 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. conclusion: 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.