Sex Difference and Testosterone Modulation: RESULTS(1)

15 Mar
2013

Experiment 1: Neuronal Fos-IR Responses in the Chemosensory Pathway after Exposure to Soiled Female Bedding or Peppermint Odors

Odors from estrous bedding significantly augmented neuronal Fos-IR in the granule cell layer of the central and caudal MOB of gonadectomized, oil-treated male and female subjects. In both sexes, TP treatment further enhanced neuronal Fos-IR responses to estrous female odors (Figs. 2 and 3). In addition, TP treatment was needed for a neuronal Fos-IR response to occur in the rostral MOB. In both sexes, peppermint odor also augmented neuronal Fos-IR in the central and caudal MOB regions studied; however, TP treatment failed to enhance the magnitude of this effect (Fig. 3). Statistical analysis showed a significant effect of odor stimulus on the number of Fos-IR cells in the most rostral counting area (+18.8 mm; Fig. 3) of the MOB (F = 20.642, p < 0.01). buy cipro

In addition there was a significant steroid treatment X odor stimulus interaction (F = 6.055, p < 0.01), reflecting the observation that estrous odors augmented neuronal Fos-IR in this site only in TP-treated females and males. There were also significant overall effects of odor stimulus in the central MOB (F = 40.336, p < 0.01) and in the caudal MOB (F = 57.822, p < 0.01), and there were significant steroid treatment X odor stimulus interactions in these two regions (central MOB: F = 5.117, p < 0.05; caudal MOB: F = 12.679, p < 0.01).
Fig1Sex Difference and TestosteroneFIG. 1. Representative photomicrographs of coronal, Nissl-stained sections through a female ferret’s rostral (+18.8 mm in front of the interaural line), central, and caudal olfactory bulb. Odor-induced increases in the number of Fos-IR cells were counted in the areas designated. The black circles show the location of the 0.1-mm2 counting areas in the granule cell layer of the MOB. The black rectangle within the open circle in the caudal section shows the location of the 0.03-mm2 counting area in the cell layer of the AOB.

Fig2Sex Difference and TestosteroneFIG. 2. Representative photomicrographs of Fos-IR cells in the caudal counting region (black circles) of the MOB from gonadectomized oil- and TP-treated female and male ferrets exposed to either a clean cage or to soiled estrous bedding in experiment 1. EPL, external plexiform layer; MCL, mitral cell layer; GCL, granule cell layer.

Fig3Sex Difference and TestosteroneFIG. 3. Right) Mean number (± SEM) of Fos-IR cells in the granule cell layer of the rostral (+18.8 mm in front of the interaural line), central, and caudal MOB and in the AOB. *p < 0.05 compared to clean-cage control animals using post-hoc Student-Neuman-Keuls tests following a significant three-way ANOVA. +p < 0.05 compared to oil-treated, pheromone-exposed animals by post-hoc Student Neuman-Keuls tests following a significant three-way ANOVA. Left) Schematic drawings showing the location of the Fos-IR cell counting areas at three levels of the MOB (0.1 mm2) and in the AOB (0.03 mm2). GL, glomerular layer; IPL, internal plexiform layer; LOT, lateral olfactory tract; AON, anterior olfactory nucleus; and CL, AOB cell layer.

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