Alpha7nAChR agonists ameliorated the clinical course of collagen induced arthritis in animals [17]: arthritis was exacerbated by vagotomy and suppressed by oral nicotine administration; oral nicotine inhibited bone degradation and reduced TNF-α expression in synovial tissue, and ameliorated clinical arthritis and reduced synovial inflammation that was accompanied by a reduction of TNF-α level in both plasma and synovial tissue. Here, TNF is linked to arthritic joint disease.