Neuregulins Regulate Cardiac Parasympathetic Activity by Katashi Okoshi, Masaharu Nakayama, Xinhua Yan, Marina P. Okoshi, Adam J.T. Schuldt, Mark A. Marchionni, and Beverly H. Lorell Circulation Volume 110(6):713-717 August 10, 2004 Copyright © American Heart Association, Inc. All rights reserved.

Figure 1. Effects of carbachol (CARB) on FS and [Ca2+]i transients in the presence of isoproterenol (ISO) in myocytes from NRG-1+/− and WT mice. Figure 1. Effects of carbachol (CARB) on FS and [Ca2+]i transients in the presence of isoproterenol (ISO) in myocytes from NRG-1+/− and WT mice. In each panel, left circles represent basal stimulation with isoproterenol alone for 3 minutes. Black circles represent myocytes stimulated with isoproterenol (1 μmol/L) alone for 3, 6, and 9 minutes. Cells stimulated with isoproterenol plus carbachol are represented with white circles. In WT myocytes stimulated with isoproterenol, carbachol caused significant reduction in both FS (A; representative tracings are shown in E) and peak-systolic [Ca2+]i (B; representative tracings are shown in F). In contrast, carbachol failed to reduce contractility during β-adrenergic stimulation in myocytes from NRG-1+/− myocytes (C and D; representative tracings are shown in G and H, respectively). Katashi Okoshi et al. Circulation. 2004;110:713-717 Copyright © American Heart Association, Inc. All rights reserved.

Figure 2. Acetylcholine nicotinic β1 and muscarinic M2 receptors protein levels. Figure 2. Acetylcholine nicotinic β1 and muscarinic M2 receptors protein levels. A, In brain lysate, the protein level of nicotinic β1 receptor was lower in NRG-1+/− mice than in WT animals. B, In LV membranes, the muscarinic M2 receptor protein level was not different between NRG-1+/− and WT mice. n=5 experiments per group. Katashi Okoshi et al. Circulation. 2004;110:713-717 Copyright © American Heart Association, Inc. All rights reserved.