Reduced N‐Type Ca ²⁺ Channels in Atrioventricular Ganglion Neurons Are Involved in Ventricular Arrhythmogenesis

Figures

• 

  Figure 1. A, AVG microinjection under a rat left posterolateral thoracotomy. LCV indicates left cranial vein; LPV, left pulmonary vein; MPV, middle pulmonary vein. B, Expression of pGFP protein in rat cholinergic AVG neurons after in vivo lentiviral transfection of Cav2.2‐α shRNA with pGFP cDNA. C, Expression of Cav2.2‐α mRNA in DiI‐labeled AVG neurons from all groups of rats, measured by single‐cell real‐time RT‐PCR. N=20 neurons from 6 rats in each group. D, Expression of Cav2.2‐α protein in the AVG from all groups of rats, measured by reverse‐phase protein microarray. N=3 rats in each group. Data are means±SEM. Statistical significance in Figure 1C‐D was determined by 1‐way anova with post hoc Dunnett test against the sham group. *P<0.05 vs sham. AVG indicates atrioventricular ganglion; ChAT, choline acetyltransferase; pGFP, phosphorylated green fluorescent protein; RT‐PCR, reverse‐transcription polymerase chain reaction.

• 

  Figure 2. Western blot image for expression of Cav2.2‐α protein in rat brain and gastrocnemius muscle with or without peptide antigen. Rat brain was used as Cav2.2‐α–positive tissue, and gastrocnemius muscle was used as Cav2.2‐α–negative tissue.

• 

  Figure 3. A, original recording of Ca2+ currents (a), current‐voltage curve (b), and mean data (c, at 5‐mV test voltage) of N‐type Ca2+ currents in DiI‐labeled AVG neurons from all groups of rats. B, original recording of action potentials (a) and frequency of action potentials (b) in DiI‐labeled AVG neurons from all groups of rats. ω‐Conotoxin GVIAis a specific N‐type Ca2+ channel blocker. Data are means±SEM from n=8 neurons from 6 rats in each group. Statistical significance was determined by 1‐way repeated‐measures anova with post hoc Dunnett test against the sham group in (Ab and Bb), and 1‐way anova with post hoc Dunnett test against the sham group in 3Ac, respectively. *P<0.05 vs sham. AVG indicates atrioventricular ganglion.

• 

  Figure 4. Representative tracings of the LVP (A), and mean data showing changes of the LVSP (B) and LV dP/dtmax (C) in response to different frequency of left vagal efferent nerve stimulation in all groups of anesthetized rats. LVindicates left ventricle; LV dP/dtmax, peak rate of change of LVP; LVP, left ventricular pressure; LVSP, left ventricular systolic pressure. Data are means±SEM; n=6 rats in each group. Statistical significance was determined by 1‐way repeated‐measures with post hoc Dunnett test against the sham group (B and C). *P<0.05 vs sham.

• 

  Figure 5. A, Raw data for induction of ventricular arrhythmias evoked by programmed electrical stimulation (S1‐4). B and C, Incidence and inducibility quotient of ventricular arrhythmias in all groups of rats. Data are means±SEM; n=6 rats in each group. Statistical significance was determined by Fisher exact test (B) or 1‐way ANOVA with post hoc Dunnett test against the sham group (C), respectively. *P<0.05 vs sham.

• 

  Figure 6. Representative data of ECG recording (A), mean data for incidence of ventricular arrhythmia (B), and the number of premature ventricular contraction (PVC) in all groups of conscious rats. Data are means±SEM; n=6 rats in each group. Statistical significance was determined by Fisher exact test (B) or by 1‐way ANOVA with post hoc Dunnett test against the sham group (C). *P<0.05 vs sham.

• 

  Figure 7. A, Representative signal of electrocardiographic recordings illustrating QT intervals and T‐peak to T‐end interval (Tpe) in sham and Cav2.2‐α shRNA transfected rats. B through F, Mean data for QT intervals, QTc intervals, QT dispersions (QTd), QTc dispersions (QTcd), and Tpe in all groups of conscious rats. Data are means±SEM; n=6 rats in each group. Statistical significance was determined by 1‐way ANOVA with post hoc Dunnett test against the sham group for comparison among multiple groups or by paired t test for comparison between before and after treatments, respectively. *P<0.05 vs sham; † P<0.05 vs before treatment.