TNF and Anxiety: To support the hypothesis that circulating TNF-α released 1–4 h post-SPS resulted in SPS-induced allodynia, hyperalgesia and anxiety-like behaviors, male and female SD rats were divided into one of four groups: Sham Control + normal rat serum (Ctr/IgG), Sham Ctr + anti-TNF-α antibody (Ctr/α-TNF-α), SPS+IgG and SPS + α-TNF-α.