Rabbit Anti-Human RYR2 Polyclonal antibody

BACKGROUND Ryanodine receptor (RyR) dysfunction in skeletal muscle (RyR1) leads to malignant hyperthermia, and in cardiac muscle (RyR2) triggers cardiac arrhythmias. We hypothesized that RyR dysfunction in vascular smooth muscle could increase vascular resistance and hypertension, and may contribute to increased atrial fibrillation (AF) in hypertension. Thus, stabilizing RyR function with chronic dantrolene treatment may attenuate hypertension and AF inducibility in spontaneously hypertensive rats (SHR). METHODS Male SHR (16 weeks old) were randomized into vehicle- (n = 10) and dantrolene-treated (10 mg/kg/day, n = 10) groups for 4 weeks. Wistar Kyoto (WKY, n = 11) rats served as controls. Blood pressures (BP) were monitored before and during the 4-week treatment. After 4-week treatment, direct BP, echocardiography, and hemodynamics were recorded. AF inducibility tests were performed in vivo at baseline and repeated under sympathetic stimulation (SS). RESULTS Compared with WKY, SHR had significantly higher BP throughout the experimental period. Dantrolene treatment had no effect on BP levels in SHR (final systolic BP 212 9 mm Hg in vehicle group vs. 208 +/- 16 mm Hg in dantrolene group, P > 0.05). AF inducibility was very low and not significantly different between 5-month-old WKY and SHR at baseline. However, under SS, AF inducibility and duration were significantly increased in SHR (20% in WKY vs. 60% in SHR-vehicle, P<0.05). Dantrolene treatment significantly attenuated AF inducibility under SS in SHR (60% in vehicle vs. 20% in dantrolene, P < 0.05). CONCLUSIONS Stabilizing RyR with chronic dantrolene treatment does not affect hypertension development in SHR. SHR has increased vulnerability to AF induction under SS, which can be attenuated with dantrolene treatment.

Aconitine (ACO), the main active component in Aconitum carmichaelii Debeaux (family: Ranunculaceae), has high cardiotoxicity, however the mechanisms of this effect remain unclear. Paeoniflorin (PF), the main chemical ingredient in herbaceous peony, can protect the heart from damage through antioxidant, vasodilatory and other effects. In this study, we focused on the mechanism by which PF reduces ACO cardiotoxicity. We selected H9c2 cells as the experimental model. MTT assay, Western blot analysis and real-time PCR were used to measure cell proliferation, apoptosis, ion channels and oxidative stress. Cell proliferation was significantly increased, the Bcl-2/Bax ratio and p53 level were upregulated, and Caspase-3 was slightly reduced in the ACO+PF group compared with the ACO group. SCN5A mRNA expression was significantly increased in the ACO+PF group compared with the ACO group, while RyR2 and Cx43 mRNA expression was decreased. Compared with the ACO group, the ACO+PF group showed marked decreases in extracellular lactate dehydrogenase (LDH) and intracellular malondialdehyde (MDA), while there was no difference in intracellular superoxide dismutase (SOD). The above data demonstrate that the cardiotoxicity of ACO in H9c2 cells was significantly decreased by PF.