ROLE OF THE AMYGDALA IN THE COORDINATION OF BEHAVIORAL, NEUROENDOCRINE, AND PREFRONTAL CORTICAL MONOAMINE RESPONSES TO PSYCHOLOGICAL STRESSIN THE RAT

Exposure to mild stress is known to activate dopamine (DA), serotonin (5-HT), and norepinephrine (NE) metabolism in the anteromedial prefron tal cortex (m-PFC). Neuroanatomical site(s) providing afferent control of the stress activation of the m-PFC monoaminergic systems is at pre sent unknown. The present study used a conditioned stress model in whi ch rats were trained to fear a substartle-threshold tone paired previo usly with footshock and assessed for behavioral, neuroendocrine, and n eurochemical stress responses. Bilateral NMDA-induced excitotoxic lesi oning of the basolateral and central nuclei of the amygdala was perfor med before or after training. Pretraining amygdala lesions blocked str ess-induced freezing behavior, ultrasonic vocalizations, adrenocortica l activation, and dopaminergic metabolic activation in the m-PFC. Post -training amygdala lesions blocked stress-induced m-PFC DA, 5-HT, and NE metabolic activation. Post-training amygdala lesions also blocked s tress-induced freezing and defecation, and greatly attenuated adrenoco rtical activation, These data provide evidence of amygdalar control of stress-induced metabolic activation of the monoaminergic systems in t he m-PFC, as well as amygdalar integration of behavioral and neuroendo crine components of the rat stress response. These results are discuss ed in terms of possible relevance to stress-induced exacerbation of sc hizophrenic symptoms and the pathophysiology of posttraumatic stress d isorder.