A: effect of injection of muscimol into rostral l/dlPAG on cardiovascular response to air jet stress. Mean values for HR and MAP over time (min) after microinjection of VEH (100 nl; •) or MUS (300 pmol/100 nl; ○) into rostral l/dlPAG at t = 5 min followed 5 min later by 20 min of air jet stress (n = 5). Two-factor repeated-measures ANOVA (treatment and time as repeated factors) revealed no significant differences for interaction of treatment × time − HR: F (17, 51) = 1.00, P = 0.47; MAP: F (17, 51) = 0.64, P = 0.84. B: schematic coronal sections of the rat brain adapted from the atlas of Paxinos and Watson (35), illustrating approximate sites of injections of muscimol into rostral l/dlPAG in experiments, for which data are reported at left. Numbers indicate distance from bregma in millimeters.