Background-The therapeutic potential of 2-adrenergic receptor (AR) agonists in the treatment of autoimmune diseases has been reported. However, the role of these drugs in the myocardial structure-induced autoimmune process, which is thought to play a crucial role in the progression of myocarditis to subsequent complications, has not been elucidated. Methods and Results-Experimental autoimmune myocarditis (EAM) was induced in rats by immunization with cardiac myosin. On daily administration from day 0 after immunization, the 2-selective AR agonists formoterol or salbutamol ameliorated EAM on day 21 and increased myocardial interleukin-10/interferon-␥ mRNA levels. Propranolol, a nonselective -AR antagonist, aggravated EAM on day 21 and decreased mRNA levels, whereas metoprolol, a 1-selective AR antagonist, showed no effect. These results were reflected in vivo by the proliferation of cardiac myosin-primed lymph node cells from drug-treated rats. In vitro addition of 2-selective AR agonists inhibited the activation of cardiac myosin fragment-specific myocarditogenic T lymphocytes, and this effect was reversed by ICI118,551, a 2-selective AR antagonist. Furthermore, treatment with 2 different 2-selective AR agonists starting on day 14 also ameliorated EAM on day 21.
Conclusions-2-AR