Figure 1: Density of , , and receptor subunit-immunoreactive neurones
in the PAG in (a) spontaneously cycling female rats and (b) rats that had
undergone a progesterone withdrawal regime. Abbreviations: P: proestrus; O: oestrus; ED: early dioestrus; LD: late
dioestrus; HP: high progesterone; VEH: vehicle treated; PWD: progesterone-withdrawn.
for each group, all values . ,
post hoc Fischer
test after significant () one-way ANOVA. Data redrawn from [31, 32].