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cAMP-PKA通路参与Ⅱ组代谢性谷氨酸受体对新生鼠离体延髓脑片呼吸节律性放电的调节

郑奇辉, 李国才, 程静, 方芳, 吴中海^*

南方医科大学生理教研室，广州 510515；广东省中医院麻醉科，广州 510120

摘要

本研究旨在探讨cAMP-PKA通路在Ⅱ组代谢性谷氨酸受体对离体延髓脑片呼吸节律性放电的影响中的作用。制作新生大鼠离体延髓脑片标本，主要包含延髓面神经后核内侧区(medial region of the nucleus retrofacialis, mNRF)，并完整保留舌下神经根，以改良Kreb’s液(modified Kreb’s solution, MKS)恒温灌流脑片，用吸附电极记录舌下神经根呼吸节律性放电活动(respiratory rhythmical discharge activity, RRDA)。待放电活动稳定后，第1组灌流Ⅱ组代谢性谷氨酸受体特异性拮抗剂(2S)-α-ethylglutamic acid (EGLU) 10 min，第2组先给予cAMP-PKA通路激动剂Forskolin灌流10 min，而后MKS洗脱至正常，灌流cAMP-PKA通路抑制剂Rp-cyclic 3’, 5’-hydrogen phosphorothioate adenosine triethylammonium salt (Rp-cAMPS) 10 min，第3组首先给予Rp-cAMPS 10 min，洗脱后联合Rp-cAMPS + EGLU持续灌流10 min，记录各组各时间点RRDA的变化。结果显示，给予Ⅱ组代谢性谷氨酸受体拮抗剂EGLU后，呼吸周期(respiratory cycle, RC)缩短，放电积分幅度(integral amplitude, IA)和吸气时程(inspiratory time, TI)没有变化；Forskolin兴奋呼吸，缩短RC，增加IA，延长TI；Rp-cAMPS则延长RC，降低IA，缩短TI；并且cAMP-PKA通路被阻断之后，EGLU缩短RC的效应也被抑制。这些结果提示在离体延髓水平上，cAMP-PKA通路参与了Ⅱ组代谢性谷氨酸受体对脑片呼吸节律性放电的调节。

关键词： 延髓; 呼吸节律; Ⅱ组代谢性谷氨酸受体; cAMP-PKA通路

分类号：Q42，R338.2

[Involvement of cAMP-PKA pathway in group Ⅱ metabotropic glutamate receptors-mediated regulation of respiratory rhythm from neonatal rat brainstem slice.] [Article in Chinese]

ZHENG Qi-Hui, LI Guo-Cai, CHENG Jing, FANG Fang, WU Zhong-Hai^*

ZHENG Qi-Hui； LI Guo-Cai； CHENG Jing； FANG Fang； WU Zhong-Hai

Abstract

The study aims to identify the role of cAMP-PKA pathway in the group Ⅱ metabotropic glutamate receptors (mGluRs)-mediated regulation of respiratory rhythm from the brainstem slice. Neonatal (aged 0–3 d) Sprague-Dawley rats of either sex were used. The brainstem slice containing the medial region of the nucleus retrofacialis (mNRF) and the hypoglossal nerve rootlets was prepared, and the surgical procedure was performed in the modified Kreb’s solution (MKS) with continuous carbogen (95% O2 and 5% CO2) bubbling, and ended in 3 min. Respiratory rhythmical discharge activity (RRDA) of the hypoglossal nerve rootlets was recorded by suction electrode. Eighteen brainstem slice preparations were divided into 3 groups. In group 1, group Ⅱ mGluRs specific antagonist (2S)-α-ethylglutamic acid (EGLU) was added into the perfusion solution for 10 min. In group 2, after application of Forskolin for 10 min, washout with MKS, the slice was perfused with Rp-cyclic 3’, 5’-hydrogen phosphorothioate adenosine triethylammonium salt (Rp-cAMPS) alone for another 10 min. In group 3, after application of Rp-cAMPS for 10 min, additional EGLU was added into the perfusion for another 10 min. The results showed EGLU shortened respiratory cycle (RC), but the changes of integral amplitude (IA) and inspiratory time (TI) were not statistically significant. Forskolin induced significant decreases in RC, and increased TI, IA. Rp-cAMPS could make the opposite effect compared with the changes of RRDA with Forskolin. The effect of EGLU on the RRDA was inhibited after blocking the cAMP-PKA pathway. Taken together, cAMP-PKA pathway may play an important role in the group Ⅱ mGluRs-mediated regulation of RRDA in the brainstem slice of neonatal rats.

Key words: medulla oblongata; respiratory rhythm; group Ⅱ mGluRs; cAMP-PKA pathway

收稿日期：2010-12-15　　录用日期：2011-03-11

通讯作者：吴中海　　E-mail: wzh@fimmu.com

引用本文：

郑奇辉, 李国才, 程静, 方芳, 吴中海. cAMP-PKA通路参与Ⅱ组代谢性谷氨酸受体对新生鼠离体延髓脑片呼吸节律性放电的调节[J]. 生理学报 2011; 63 (3): 233-237.

ZHENG Qi-Hui, LI Guo-Cai, CHENG Jing, FANG Fang, WU Zhong-Hai. [Involvement of cAMP-PKA pathway in group Ⅱ metabotropic glutamate receptors-mediated regulation of respiratory rhythm from neonatal rat brainstem slice.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (3): 233-237 (in Chinese with English abstract).