Role of the amygdala in the coordination of behavioral, neuroendocrine, and prefrontal cortical monoamine responses to psychological stress in the rat

J Neurosci. 1996 Aug 1;16(15):4787-98. doi: 10.1523/JNEUROSCI.16-15-04787.1996.

Abstract

Exposure to mild stress is known to activate dopamine (DA), serotonin (5-HT), and norepinephrine (NE) metabolism in the anteromedial prefrontal cortex (m-PFC). Neuroanatomical site(s) providing afferent control of the stress activation of the m-PFC monoaminergic systems is at present unknown. The present study used a conditioned stress model in which rats were trained to fear a substartle-threshold tone paired previously with footshock and assessed for behavioral, neuroendocrine, and neurochemical stress responses. Bilateral NMDA-induced excitotoxic lesioning of the basolateral and central nuclei of the amygdala was performed before or after training. Pretraining amygdala lesions blocked stress-induced freezing behavior, ultrasonic vocalizations, adrenocortical 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 stress-induced freezing and defecation, and greatly attenuated adrenocortical activation. These data provide evidence of amygdalar control of stress-induced metabolic activation of the monoaminergic systems in the m-PFC, as well as amygdalar integration of behavioral and neuroendocrine components of the rat stress response. These results are discussed in terms of possible relevance to stress-induced exacerbation of schizophrenic symptoms and the pathophysiology of posttraumatic stress disorder.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3,4-Dihydroxyphenylacetic Acid / metabolism
  • Amygdala / physiology*
  • Animals
  • Behavior, Animal / physiology*
  • Biogenic Monoamines / metabolism*
  • Corticosterone / metabolism
  • Male
  • Prefrontal Cortex / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Stress, Psychological / metabolism
  • Stress, Psychological / physiopathology*

Substances

  • Biogenic Monoamines
  • 3,4-Dihydroxyphenylacetic Acid
  • Corticosterone