TABLE 2. Major preclinical evidence supporting noradrenergic contributions to anxiety and fear


Stress and fear inducing stimuli

increase firing rate.


Stress induces increase in

norepinephrine (NE) turnover

in Limbic Brain Regions.


Stress and LC activation

increase tyrosine

hydroxylase and C-fos

expression in the LC.


Conditioned fear is associated

with increased LC neuronal

activity and increased NE

turnover in LC projection



Electrical and Pharmacological

activation of LC results in

anxiety and fear behavior.


Drugs, which have anxiolytic

activity, decrease stress

induced increases in NE

turnover and LC firing rate.


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published 2000