PT - JOURNAL ARTICLE AU - Yixin Jing AU - Miaomiao Dong AU - Yu Liu AU - Xiaomin Hou AU - Pengmei Guo AU - Weiping Li AU - Mingsheng Zhang AU - Jiyuan Lv TI - Apigenin relaxes rat intrarenal arteries: involvement of Cl<sup>−</sup> channels and K<sup>+</sup> channels AID - 10.1101/371849 DP - 2018 Jan 01 TA - bioRxiv PG - 371849 4099 - http://biorxiv.org/content/early/2018/07/18/371849.short 4100 - http://biorxiv.org/content/early/2018/07/18/371849.full AB - The vasodilator effect of apigenin (API) was demonstrated in a number of vascular beds. We aimed to characterize the vasospasmolytic and electrophysiological effects of apigenin (API) in intrarenal arteries (IRAs). The vascular tone of male rat isolated IRAs was recorded with a myograph. Transmembrane Cl− currents through Ca2+-activated Cl− channels (CaCCs), K+ currents through voltage-gated K+ (Kv) channels and inwardly rectifier K+ (Kir) channels were recorded with patch clamp in the freshly isolated arterial smooth muscle cells (ASMCs). Preincubation with API (10-100 μM) concentration-dependently depressed the contractions induced by KCl, 9,11-dideoxy-9α,11α-methanoepoxy prostaglandin F2α (U46619), phenylephrine and vasopressin without significant preference and the IC50 values were 13.27-26.26 μM. Acute application of API elicited instant relaxations in the IRAs precontracted with these vasoconstrictors and the RC50 values were 5.80-24.33 μM. API relaxation was attenuated by chloride deprivation, CaCC blockers, Kv blocker and nitric oxide synthase inhibitor, but not by Kir blocker and cyclooxygenase inhibitor. At 10-100 μM, API depressed CaCC currents and Kir currents while enhanced Kv currents of IRA ASMCs. The present results demonstrate that API counteracts various vasoconstrictors noncompetitively and nonspecifically and suggest that modulation of CaCCs, Kv and Kir channels of IRA ASMCs is involved in its vasospasmolytic effects.This study was supported by the National Natural Science Foundation of China (NSFC 81773738 to MZ, NSFC81603111 to YL) and the Fund for Shanxi “1331 Project” Key Subjects Construction.