EFFECTS OF CHRONIC SOCIAL STRESS ON TYROSINE-HYDROXYLASE MESSENGER-RNA AND PROTEIN-LEVELS

Males housed in mixed sex groups quickly form dominance hierarchies; s ubordinates can be further subdivided into stress responsive subordina tes (SRS) and non-responsive subordinates (NRS) based on corticosteron e responses to a novel stressor. Tyrosine hydroxylase (TH) mRNA levels measured with in situ hybridization were elevated in locus coeruleus (LC) of NRS compared to singly or pair-housed controls; NRS also had h igher TH levels than dominants. TH protein levels determined by immuno autoradiography were also higher in LC of NRS and SRS versus pair-hous ed controls.