RESUMEN
Objective To study the effects of persistent atrial fibrillation (AF) on the expression of k1 opioid receptor and change of ultrastructure in heart atrium.Methods The mRNA and protein expressions of κ1 receptor in atrial tissue were detected with RT-PCR and immunochemistry,respectively,in 24 patients with AF and 24 patients with sinus rhythm (SR).Mitochondria were analyzed in the atrial tissue by electron microscopy in 4 patients with AF and 4cases with SR.Results The κ1 receptor mRNA in patients with AF was lower than in patients with SR (262±20 vs.196± 11,P＜0.05),and amount of protein expression was also deduced (1261±90vs.2325± 131,P＜0.05).Mitochondria size was decreased in persistent AF compared with SR[(1.0±0.2) μm vs.(0.8±0.2) μm,P＜0.05].Conclusions The decrease of k1 receptor expression suggests reduction of atrial protective capacity in persistent AF,combining with remodeling of ultrastructure.