Investigation of Mechanisms of Volatile Anesthetic Action by the Use of Gene Expression Techniques

利用基因表达技术研究挥发性麻醉作用机制

• 批准号: 12671489
• 负责人: YAMAKAGE Michiaki
• 金额: $ 2.18万
• 依托单位: Sapporo Medical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12671489/
• 关键词: Patch clamp technique; Cardiac myocyte; β subunit; Cloning technique; Calcium channel; Single channel; Potassium channel; KvLQT1 gene; カルシムウムチャネル; 吸入麻酔薬; 静脈麻酔薬; アフリカツメガエル; 気道平滑筋; 子宮平滑筋; 心筋細胞カルシウムチャネル; ナトリウムチャネル

In the first year of this investigation, we investigated the effects of the volatile anesthetics isoflurane and sevoflurane on cloned I_<Ks> coexpressed by KvLQT1 and minK. Currents were induced following injection into oocytes of KvLQT1 mRNA with or without minK mRNA, which were transcribed in vitro from cDNAs of normal rats hearts. A Two-electrode voltage-clamp recording technique was used to investigate the effects of isoflurane (0-1.5 MAC) and sevoflurane (0-1.5 MAC) on I_<Ks> (KvLQT1 with mink) and KvLQT1 alone currents. Following a 2-s depolarization to +40 mV, isoflurane and sevoflurane caused potency-dependent reductions in I_<Ks> and KvLQT1 currents. Both of the volatile anesthetics tested accelerated the deactivation of I_<Ks> and KvLQT1 currents. We conclude that the significant inhibitory effect of volatile anesthetics on the cloned I_<Ks > may partly contribute to the clinical observations of the prolongation of the ventricular repolarization (Q-T interval) by the anesthetics. In the following year, we cloned another truncated splice variant of LCNQ1 from rat heart. Judging from the deleted sequence of the TCNQT1, the genomic structure of rat in this portion might be different from those of human and mouse. In the last year, we investigated the single-channel properties of the Ca^<2+> channels reconstituted with β_<2a> or β_<2c> subunit, and compared them with the properties of naive channel. In contrast to β_<2a> subunit, long-lasting closings were dominant in the Ca^<2+> channel with β^<2c> subunit and the native channel. The single-channel properties of Ca^<2+> channel with β_<2c> subunit were indistinguishable from those of native channel. Those findings suggest that β_<2c> subunit is one of the functional β subunits in the rat heart.

在这项研究的第一年，我们研究了挥发性麻醉药异氟烷和七氟烷对<Ks>KvLQT 1和minK共表达的克隆I_的影响。将体外转录自正常大鼠心脏cDNA的minK mRNA与KvLQT 1 mRNA一起注入卵母细胞后，可诱导电流。采用双电极电压钳记录技术，研究了异氟醚（0- 1.5MAC）和七氟醚（0- 1.5MAC）对<Ks>水貂KvLQT 1电流和单独KvLQT 1电流的影响。在2秒去极化至+40 mV后，异氟烷和七氟烷引起I_和KvLQT 1电流的电位依赖性降低<Ks>。两种挥发性麻醉药均能加速I_<Ks>2和KvLQT 1电流的失活。结论：吸入麻醉药对克隆I_2的显著抑制作用<Ks >可能与临床观察到的麻醉药延长心室复极（Q-T间期）有关。在接下来的一年中，我们从大鼠心脏中克隆了LCNQ 1的另一个截短剪接变体。从TCNQT 1的缺失序列来看，大鼠在这一部分的基因组结构可能与人类和小鼠的基因组结构不同。在过去的一年中，我们研究了由β_或β_亚基重构的Ca^&lt;2+&gt;通道的单通道特性<2a><2c>，并与天然通道的特性进行了比较。与β_<2a>亚基相反，β^亚基和天然通道的Ca^&lt;2+&gt;通道以长持续关闭为主<2c>。含β_亚基的Ca^&lt;2+&gt;通道的单通道特性<2c>与天然通道无明显区别。这些结果表明，β_<2c>亚基是大鼠心脏的功能性β亚基之一。

项目成果

Yamakage M: "Editorial II-Effects of anesthetics agents on airway smooth muscles"Br J Anaesth. 88(5). 624-627 (2002)

Yamakage M：“社论 II - 麻醉剂对气道平滑肌的影响”Br J Anaesth。

Yamakage M, Chen X, Tsujiguchi N, Kamada Y, Namiki A: "Different inhibitory effects of volatile anesthetics on T- and L-type voltage-dependent Ca^<2+> channels in porcine tracheal and bronchial smooth muscles"Anesthesiology. 94(4). 683-693 (2001)

Yamakage M，Chen X，Tsujiguchi N，Kamada Y，Namiki A：“挥发性麻醉剂对猪气管和支气管平滑肌中 T 型和 L 型电压依赖性 Ca^<2> 通道的不同抑制作用”麻醉学。

Yamada Y, Chen X, Kobayashi T, Kamada Y, Nagashima M, Tsutsuura M, Seki S, Yamakage M, Namiki A, Tohse N: "A truncated splice variant of KCNQ1 cloned from rat heart"Biochem Biophys Res Commun. 294. 199-204 (2002)

Yamada Y、Chen X、Kobayashi T、Kamada Y、Nagashima M、Ttsutsuura M、Seki S、Yamakage M、Namiki A、Tohse N：“从大鼠心脏克隆的 KCNQ1 的截短剪接变体”Biochem Biophys Res Commun。

Tsujiguchi N: "Mechanisms of direct inhibitory action of propofol on uterine smooth muscle contraction in pregnant rats"Anesthesiology. 95・5. 1245-1255 (2001)

辻口 N：“异丙酚对妊娠大鼠子宫平滑肌收缩的直接抑制作用机制”麻醉学 95・5（2001）。

Yamakage M: "Different inhibitory mechanisms of volatile anesthetics on T-and L-type voltage-dependent Ca^<2+> channels in porcine tracheal and bronchial smooth muscles."Anesthesiology. 94・4(掲載予定). (2001)

Yamakage M：“挥发性麻醉剂对猪气管和支气管平滑肌中 T 型和 L 型电压依赖性 Ca^<2+> 通道的不同抑制机制。”麻醉学 94・4（待出版）。