Effects of rearing condition on neuroendocrine responsiveness and serotonin (5-HT; A, C and E) and dopamine (DA; B, D and F) levels following stimulus exposure (Home, white bar; No Female, light-color bar; Female, dark-color bar).

<p>EE rats (blue color) showed decreased 5-HT responsiveness in the nucleus accumbens (NAC, A) and striatum (STR, C), but not in the preoptic area (POA, E) compared with SE rats (green color). Main effects for stimulus condition were observed for both 5-HT and DA in the NAC (A and B). *<i>P</i><0.05 compared with SE, two-way ANOVA (factor rearing-conditioning-group × factor stimuli).</p

Male motivational behavior toward a female in a runway test.

<p>Male subjects in both groups ran faster through a long alley (150 cm) toward a goal box containing an estrus female. Note that male rats in both group (EE, blue bar; SE, green bar) showed comparative motivation to reach the females in terms of their runway time (A) or percent time spent in the goal area (B).</p

Effect of rearing environment on plasma testosterone level following the exposure to stimuli.

<p>Data are mean ± SEM. Two-way ANOVA revealed a significantly suppressed response in EE rats following female exposure with main effects for group and stimuli exposure.*<i>P</i><0.05 compared with Home stimuli, post-hoc test.</p

Effects of rearing condition on male copulatory behavior in 3 consecutive weekly sessions.

<p>Male rats reared in an enriched environment (EE, blue dots) showed a decreased number of ejaculations (A) and intromissions (C) and prolonged ejaculation latencies (B) compared with rats reared in a standard environment (SE, green dots). On the other hand, there were no group differences in intromission latencies (D). *<i>P</i><0.001 compared with SE, ANOVA for repeated measures.</p

Male sexual behavior of SE and EE rat.

<p>Data are mean ± SEM. PEI, post ejaculated interval; MF, mount frequency; III, inter intromission interval; IR, intromission ratio. *<i>P</i><0.05, **<i>P</i><0.01 compared with SE group, ANOVA for repeated measures.</p

Behavioral emotionality of male rats reared in an EE (blue bar) in an open field that was the same field used in the copulatory behavior test.

<p>Group differences were observed in total distance travelled (A) and the proportion of time spent in the center area (B). ** <i>P</i><0.001, *<i>P</i><0.005 compared with SE (green bar), Student's t-test.</p

Effect of rearing environment on plasma corticosterone level following the exposure to stimuli.

<p>Data are mean ± SEM. Two-way ANOVA revealed a significantly suppressed response in EE rats following female exposure with a main effect group. *<i>P</i><0.05 compared with SE, post-hoc test.</p

Time course of body weight changes after exercise.

<p>Values represent means ± standard deviation. S, Ex, and S × Ex denote the main effects of animal strain, exercise, and interaction between animal strain and exercise, respectively. These effects were significant at 28 days (<i>p</i> < 0.05).</p

Representative sections stained with alkaline phosphatase (A), C/F ratio (B), NOS activity (C), expression levels of VEGF mRNA (D) and TSP-1 (E) mRNA, and ratio of VEGF to TSP-1 mRNA expression level (F) in the soleus muscle.

<p>Bar = 100 μm. For the expression levels of VEGF and TSP-1 mRNA, the values were calculated as fold changes relative to the LETO Cont group. Values represent means ± standard deviation. S, Ex, and S × Ex denote significant (<i>p</i> < 0.05) main effects of animal strain, exercise, and interaction between animal strain and exercise, respectively.</p

Muscle wet weight (A), representative sections of the soleus muscle stained with Sudan red (B) and staind for ATPase activity (C), muscle fiber type distribution (D), and muscle fiber cross-sectional area (E).

<p>Arrow heads: ectopic lipid accumulation. Bar = 100 μm. Values represent means ± standard deviation., Ex, and S × Ex denote significant (<i>p</i> < 0.05) main effects of animal strain, exercise, and interaction between animal strain and exercise, respectively.</p