Department of Cellular and Molecular Medicine, Laboratory of Ion Channel Research, KU Leuven, VIB Center for Brain & Disease Research, Herestraat 49, Campus Gasthuisberg, O&N1 Box 802, 3000 Leuven, Belgium; Departamento de Bioquímica y Biología Molecular y Fisiología, Instituto de Biología y Genética Molecular, Universidad de Valladolid y CSIC, Sanz y Forés 3, 47003 Valladolid, Spain.
Department of Cellular and Molecular Medicine, Laboratory of Ion Channel Research, KU Leuven, VIB Center for Brain & Disease Research, Herestraat 49, Campus Gasthuisberg, O&N1 Box 802, 3000 Leuven, Belgium.
J Mol Cell Cardiol. 2019 Apr;129:219-230. doi: 10.1016/j.yjmcc.2019.03.003. Epub 2019 Mar 7.
The Transient Receptor Potential Melastatin 3 (TRPM3) is a Ca-permeable non-selective cation channel activated by the neurosteroid pregnenolone sulfate (PS). This compound was previously shown to contract mouse aorta by activating TRPM3 in vascular smooth muscle cells (VSMC), and proposed as therapeutic modulator of vascular functions. However, PS effects and the role of TRPM3 in resistance arteries remain unknown. Thus, we aimed at determining the localization and physiological role of TRPM3 in mouse mesenteric arteries. Real-time qPCR experiments, anatomical localization using immunofluorescence microscopy and patch-clamp recordings in isolated VSMC showed that TRPM3 expression in mesenteric arteries is restricted to perivascular nerves. Pressure myography experiments in wild type (WT) mouse arteries showed that PS vasodilates with a concentration-dependence that was best fit by two Hill components (effective concentrations, EC, of 14 and 100 μM). The low EC component was absent in preparations from Trpm3 knockout (KO) mice and in WT arteries in the presence of the CGRP receptor antagonist BIBN 4096. TRPM3-dependent vasodilation was partially inhibited by a cocktail of K channel blockers, and not mediated by β-adrenergic signaling. We conclude that, contrary to what was found in aorta, PS dilates mesenteric arteries, partly via an activation of TRPM3 that triggers CGRP release from perivascular nerve endings and a subsequent activation of K channels in VSMC. We propose that TRPM3 is implicated in the regulation of the tone of resistance arteries and that its activation by yet unidentified endogenous damage-associated molecules lead to protective vasodilation responses in mesenteric arteries.
瞬时受体电位 melastatin 3（TRPM3）是一种钙通透性非选择性阳离子通道，可被神经甾体孕烯醇酮硫酸盐（PS）激活。该化合物先前被证明可通过激活血管平滑肌细胞（VSMC）中的 TRPM3 来收缩小鼠主动脉，并被提议作为血管功能的治疗调节剂。然而，PS 效应和 TRPM3 在阻力动脉中的作用仍不清楚。因此，我们旨在确定 TRPM3 在小鼠肠系膜动脉中的定位和生理作用。实时 qPCR 实验、免疫荧光显微镜的解剖定位以及分离的 VSMC 中的膜片钳记录表明，肠系膜动脉中 TRPM3 的表达仅限于血管周围神经。在野生型（WT）小鼠动脉中的压力肌动描记术实验表明，PS 具有浓度依赖性的血管舒张作用，该作用通过两个 Hill 分量（有效浓度，EC，为 14 和 100μM）得到最佳拟合。在 Trpm3 敲除（KO）小鼠的制剂中不存在低 EC 分量，并且在 WT 动脉中存在 CGRP 受体拮抗剂 BIBN 4096 的情况下也不存在。TRPM3 依赖性血管舒张部分被 K 通道阻断剂混合物抑制，并且不由β-肾上腺素能信号介导。我们得出结论，与在主动脉中发现的情况相反，PS 舒张肠系膜动脉，部分通过激活 TRPM3 触发血管周围神经末梢释放 CGRP，随后在 VSMC 中激活 K 通道。我们提出，TRPM3 参与调节阻力动脉的张力，并且其通过尚未确定的内源性损伤相关分子的激活导致肠系膜动脉中的保护性血管舒张反应。
