Systemic effects of oxytocin on male sexual activity via the spinal ejaculation generator in rats

Figures & data

Figure 1. Effects of intraperitoneal administration of oxytocin on male sexual activity. Oxytocin shortens latencies to the first mount, intromission, and ejaculation [Data are presented as mean ± SEM and individual point (black), n = 11; paired t test, Mount latency: t₁₀ = 2.53; Intromission latency: t₁₀ = 2.30; Ejaculation latency: t₁₀ = 2.55; Mount number: t₁₀ = 0.03; Intromission number: t₁₀ = 1.26; Ejaculation number: t₁₀ = 1.88, *P < 0.05]

Figure 2. (a) Local concentrations of oxytocin and vasopressin in the lumbar spinal cord. [Data are presented as mean ± SEM (highlight) and individual point (black). Student’s unpaired t test; oxytocin, t₉ = 3.25, *P < 0.05; vasopressin, t₉ = 1.19, P = 0.133, male rats (n = 6), female rats (n = 5).] (b) Oxytocin-binding is apparent in the spinal GRP neurons (green). Left panel indicates the GRP⁺ neuronal cell bodies (green). Middle panel shows that oxytocin-binding is detected in the cytoplasm (chromogen aggregates) of GRP⁺ neuronal cell bodies. Right panel indicates the negative control sections incubated with biotinylated oxytocin and excess free oxytocin. Asterisks indicate the location of neuronal nuclei expressing GRP and oxytocin-binding double-positive neurons or binding-negative neurons (control). Scale bar: 20 µm