Figure 4. Effects of CSC on plasma ACTH and corticosterone responses to an acute heterotypic stressor.

<p>On day 20 after 19 days of CSC exposure, CSC (n = 11), together with single-housed (SHC; n = 11) and group-housed (GHC; n = 10–12) control rats were chronically catheterized. On day 25, i.e. 5 days after recovery from jugular vein catheter surgery, blood was sampled under basal conditions (2 basal 200-µl samples were taken 30 min apart and averaged), and 5, 15 and 60 min after open arm exposure (5 min). Whereas basal plasma ACTH (insert A) and corticosterone (insert B) were not different between the groups, CSC rats showed a more pronounced plasma corticosterone (B) response 5 and 15 min following termination of open arm exposure compared with both SHC and GHC rats, despite comparable ACTH (A) responses between the different groups at all time points measured. Data represent means ± S.E.M.; # p<0.05 versus SHC and GHC, * p<0.05 versus respective basal values.