Percentages of cells in the PdPN, MPNm, and lateral MeApd of male gerbils in which NOS was co-localized with AR or with Fos after ejaculation. A: Percent of Fos-IR cells in recently mated males that contained NOS. B–C: Percent of NOS cells that expressed Fos after mating (B) or that contained AR (C). Percent of and AR-IR cells that contained NOS (D). The areas in which cells were counted measured 0.0169, 0.0288, and 0.0256 mm2 for the PdPN, MPNm, and lateral MeApd, respectively. Note that the y-axis in C differs from that in A, B, and D. Data are shown as group means ± SEM; n = 4–5 per group. For abbreviations, see list.