EFFECTS OF IMMOBILIZATION ON IN-VIVO RELEASE OF NOREPINEPHRINE IN THEBED NUCLEUS OF THE STRIA TERMINALIS IN CONSCIOUS RATS

Release of norepinepriine (NE) and its metabolites in the bed nucleus of the stria terminalis (BNST) was examined using in vivo microdialysi s in conscious rats before, during and after 2 h of immobilization. Mi crodialysate levels of NE and of dihydroxyphenylglycol (DHPG) increase d by 170-290% above basal levels during the 1st h of immobilization an d decreased gradually thereafter. In contrast, levels of dihydroxyphen ylacetic acid (DOPAC) increased gradually over the entire period of im mobilzation, peaking at 110% above baseline levels. These findings ind icate that in rats a single immobilization is attended by increased sy nthesis, release and reuptake of NE within the BNST. The results are c onsistent with previous findings relating to stress-induced release of NE in the hypothalamic paraventricular nucleus, central nucleus of th e amygdala and cerebral cortex and suggest concurrent noradrenergic ac tivation in several brains centers during acute stress.