Fig. 2.

Chronotropic activity (∆ beats/min) of autoantibodies directed against the α1-adrenergic receptor (α1-AAB) and endothelin receptor A (ETA-AAB) in patients with prostate cancer as compared with control patients suffering from urinary stone disorders. For measurement, the bioassay of spontaneously beating cultured neonatal rat cardiomyocytes was performed in the presence of the patients’ IgG without and with the presence of specific receptor blockers (endothelin receptor A: 0.1 µmol/l BQ 123, muscarinic 2 receptor: 0.1 µmol/l atropine, β-adrenergic receptor: 0.1 µmol/l propranolol, AT-1 receptor: 0.1 µmol/l losartan, α1-adrenergic receptor: 0.1 µmol/l prazosin). Values below the lower limit of detection (LLD) were displayed as half range values. LLD = Δ 4 beats/min for α1-AAB, Δ − 4 beats/min for ETA-AAB; cut off (separating healthy from disease subjects) = Δ 8 beats per/min for α1-AAB, Δ − 8 beats/min for ETA-AAB