Rats were injected in the PVN with the group I metabotropic glutamate receptor antagonist hexyl-HIBO and/or dexamethasone (Dex), then subjected to 30 minutes of restraint. A) Time course of ACTH secretion in response to restraint. B) Area under the curve (AUC) of ACTH secretion. C) Time course of corticosterone (CORT) secretion in response to restraint. D) AUC of corticosterone secretion in C. * indicates p < 0.05 vs. vehicle, and † indicates p < 0.05 vs dexamethasone in A and vs HIBO in B. n = 8 (vehicle), 10 (hexyl-HIBO), 7 (dexamethasone), and 8 (dexamethasone/hexyl-HIBO).