Valero Marta Sofía, Oliván-Viguera Aida, Garrido Irene, Langa Elisa, Berzosa César, López Víctor, Gómez-Rincón Carlota, Murillo María Divina, Köhler Ralf
J Physiol Biochem. 2015 Dec;71(4):785-93. doi: 10.1007/s13105-015-0442-8.
In traditional herbal medicine, Rock Tea (Jasonia glutinosa) is known for its prophylactic and therapeutic value in various disorders including arterial hypertension. However, the mechanism by which Rock Tea exerts blood pressure-lowering actions has not been elucidated yet. Our aim was to demonstrate vasorelaxing effects of Rock Tea extract and to reveal its possible action mechanism. Isometric myography was conducted on high-K+-precontracted rings from rat thoracic aorta and tested extracts at concentrations of 0.5-5 mg/ml. Whole-cell patch-clamp experiments were performed in rat aortic vascular smooth muscle cells (line A7r5) to determine blocking effects on L-type Ca(2+) channels. Rock Tea extract relaxed the aorta contracted by high [K+] concentration dependently with an EC50 of ≈2.4 mg/ml and produced ≈75 % relaxation at the highest concentration tested. The L-type Ca(2+) channel blocker, verapamil (10(-6) M), had similar effects. Rock Tea extract had no effect in nominally Ca(2+)-free high-K(+) buffer but significantly inhibited contractions to re-addition of Ca(2+). Rock Tea extract inhibited the contractions induced by the L-type Ca(2+) channel activator Bay K 8644 (10(-5) M) and by phenylephrine (10(-6) M). Rock Tea extract and Y-27632 (10(-6) M), Rho-kinase inhibitor, had similar effects and the respective effects were not additive. Patch-clamp experiments demonstrated that Rock Tea extract (2.5 mg/ml) virtually abolished L-type Ca(2+) currents in A7r5. We conclude that Rock Tea extract produced vasorelaxation of rat aorta and that this relaxant effect is mediated by inhibition of L-type Ca(2+) channels. Rock Tea extracts may be of phytomedicinal value for prevention and adjuvant treatment of hypertension and other cardiovascular diseases.
在传统草药医学中，石茶（粘毛香青）因其在包括动脉高血压在内的各种疾病中的预防和治疗价值而闻名。然而，石茶发挥降压作用的机制尚未阐明。我们的目的是证明石茶提取物的血管舒张作用，并揭示其可能的作用机制。采用等长肌电图法对大鼠胸主动脉高钾预收缩环进行研究，并以0.5 - 5mg/ml的浓度测试提取物。在大鼠主动脉血管平滑肌细胞（A7r5系）中进行全细胞膜片钳实验，以确定对L型钙通道的阻断作用。石茶提取物能浓度依赖性地舒张高[K⁺]收缩的主动脉，半数有效浓度（EC50）约为2.4mg/ml，在最高测试浓度下产生约75%的舒张作用。L型钙通道阻滞剂维拉帕米（10⁻⁶M）具有相似的作用。石茶提取物在无钙高钾缓冲液中无作用，但能显著抑制再加入钙后的收缩。石茶提取物抑制L型钙通道激活剂Bay K 8644（10⁻⁵M）和去氧肾上腺素（10⁻⁶M）诱导的收缩。石茶提取物与Rho激酶抑制剂Y - 27632（10⁻⁶M）具有相似的作用，且各自的作用无相加性。膜片钳实验表明，石茶提取物（2.5mg/ml）几乎完全消除了A7r5细胞中的L型钙电流。我们得出结论，石茶提取物可使大鼠主动脉血管舒张，这种舒张作用是通过抑制L型钙通道介导的。石茶提取物可能对高血压和其他心血管疾病的预防和辅助治疗具有植物药用价值。
