Figure 2.

(A and D) Microinjection sites mapped on standard sections from Paxinos and Watson (2007). These sites were marked with injected Indian ink. In seven of the 15 rats (A), the injections were considered to be made in the dorsolateral periaqueductal gray (dlPAG). In the other eight rats (D), the injectates were administered in the lateral/ventrolateral PAG (l/vlPAG). (B and E) Thirty second averaged time courses of MAP and HR while conscious, free‐moving rats were exposed to 5 min of WNS at 90 dB. At 30–40 min prior to the onset of WNS exposure, saline (100 nL) or muscimol (300 pmol in 100 nL of saline) was bilaterally microinjected into the dlPAG (B, N = 7) or l/vlPAG (E, N = 8). Values are mean ± SEM. *P < 0.05, versus baseline, detected by Dunnett's post hoc test following one‐way repeated‐measures ANOVA. (C and F) Comparisons of 5 min averaged changes from baseline in MAP and HR between saline and muscimol microinjections into the dlPAG (C) or l/vlPAG (F) prior to WNS exposure. N.S.: no significance. *P < 0.05, saline‐microinjected versus muscimol‐microinjected, as detected by a paired t‐test.