科研之友
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摘要
In heart failure (HF), the malignant arrhythmias occur frequently; a study demonstrated that upregulation of I (KAS) resulted in recurrent spontaneous ventricular fibrillation in HF. However, the regulation of SK channels was poorly understood. The activation of SK channels depended on [Ca2+]i and PP2A; studies suggested that angiotensin II can regulate them. So, we hypothesized that in HF, the excess of angiotensin may regulate the SK channels and result in the remodeling of SK channels. To test the hypothesis, we used volume-overload-induced HF rat model, treated with captopril, performed whole-cell patch clamp to record apamin-sensitive currents (I (KAS)), and I-V curve was studied. The sensitivity of I (KAS) to [Ca2+]i was also explored by setting various [Ca2+]i (10, 100, 500, 900, 1000, and 10,000 nM), and the steady-state Ca2+ response of I (KAS) was attained and performed Hill fitting with the equation (y = 1/[1 + (EC50/x) (n) ]). Immunofluorescent staining, real-time PCR, Western blot were also carried out to furtherly investigate the underlying molecular mechanisms of the regulation. Captopril significantly decreased the mean density of I (KAS) when [Ca2+]i was 500, 900, 1000, and 10000 nM. The Hill fitting showed significantly different EC50 values and the Hill coefficients and showed captopril significantly shifted rightward the steady-state Ca2+ response of I (KAS). The results of real-time PCR and Western blot demonstrated captopril decreased the mRNA and protein expression of SK3 channels. Captopril significantly downregulated the sensitivity of SK channels to [Ca2+]i and the SK3 channels expression in HF, and reversed the SK channels remodeling.
- 出版日期2016-8
- 单位西安交通大学
