Desensitization of PKA-stimulated ciliary beat frequency in an ethanol-fed rat model of cigarette smoke exposure.
Desensitization of PKA-stimulated ciliary beat frequency in an ethanol-fed rat model of cigarette smoke exposure.
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DOI：
10.1097/01.alc.0000130805.75641.f4
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发表时间：
2004-07
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影响因子：
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通讯作者：
T. Wyatt;M. Gentry-Nielsen;Jacqueline A. Pavlik;J. Sisson
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文献类型：
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作者：
T. Wyatt;M. Gentry-Nielsen;Jacqueline A. Pavlik;J. Sisson
我们之前的研究表明，暴露于慢性乙醇的培养纤毛气道上皮细胞的纤毛搏动频率（CBF）对β激动剂刺激的反应没有增加。纤毛“逃跑反应”的丧失与乙醇介导的腺苷3′：5′-环单磷酸依赖蛋白激酶（PKA）脱敏有关，PKA是CBF刺激的已知调节成分。我们假设在体内也会发生类似的乙醇介导的CBF脱敏。方法用含不同浓度乙醇的液体饲料喂大鼠1、5周。其中一半暴露在香烟烟雾中12周，另一半则是假暴露。杀死动物，分析气管上皮细胞的CBF和PKA活性。结果：摄入含0-36%乙醇的饮食5周后，大鼠气管上皮细胞的基线CBF（约6 Hz）没有变化。异丙肾上腺素刺激未给予乙醇的对照组大鼠气管上皮细胞CBF至12 ~ 13 Hz。然而，异丙肾上腺素对26%乙醇饮食的大鼠CBF的刺激减弱到7.5 Hz，而对36%乙醇饮食的大鼠CBF没有刺激。同样，异丙肾上腺素刺激对照大鼠PKA活性增加2- 3倍，但在饲喂浓度增加的乙醇的大鼠中，PKA对异丙肾上腺素的反应减弱。饲喂36%乙醇的大鼠未观察到异丙肾上腺素刺激的PKA反应。乙醇对大鼠气管上皮细胞中环鸟苷单磷酸依赖蛋白激酶和蛋白激酶C的影响未见明显变化。香烟烟雾暴露略微提高了基线CBF，并将CBF和PKA激活的异丙肾上腺素脱敏的乙醇消耗水平降低至16%。酒精喂养1周后未见异丙肾上腺素脱敏现象。此外，36%乙醇喂养1周可刺激大鼠气管CBF和PKA。结论大鼠体内给药乙醇可减少纤毛跳动，使PKA脱敏。这提示了酗酒者粘液纤毛清除功能障碍的机制。
BACKGROUND Our previous studies have shown that the ciliary beat frequency (CBF) of cultured ciliated airway epithelial cells exposed to chronic ethanol fails to increase in response to beta-agonist stimulation. This loss of the ciliary "flight response" correlates with an ethanol-mediated desensitization of adenosine 3':5'-cyclic monophosphate-dependent protein kinase (PKA), a known regulatory component of CBF stimulation. We hypothesized that a similar ethanol-mediated desensitization of CBF would occur in vivo. METHODS Sprague Dawley rats were fed a liquid diet containing various concentrations of ethanol for 1 or 5 weeks. Half were exposed to cigarette smoke for 12 weeks and half were sham exposed. Animals were killed and tracheal epithelial cells analyzed for CBF and PKA activity. RESULTS Baseline CBF (approximately 6 Hz) was unchanged in tracheal epithelial cells of rats consuming diets containing 0-36% ethanol for 5 weeks. Isoproterenol stimulated CBF to 12 to 13 Hz in the tracheal epithelial cells of control rats not administered ethanol. However, isoproterenol stimulation of CBF was blunted to 7.5 Hz in rats eating a 26% ethanol diet, and there was no stimulation of CBF in rats fed a diet containing 36% ethanol. Similarly, isoproterenol stimulated a 2- to 3-fold increase in PKA activity in control rats, but this PKA response to isoproterenol was blunted in rats fed increasing concentrations of ethanol. No isoproterenol-stimulated PKA response was observed in rats fed 36% ethanol. No ethanol-induced changes in cyclic guanosine monophosphate-dependent protein kinase or protein kinase C were observed in the rats' tracheal epithelial cells. Cigarette smoke exposure slightly elevated baseline CBF and lowered the ethanol consumption level for isoproterenol-desensitization of CBF and PKA activation to 16%. No isoproterenol desensitization was observed after 1 week of alcohol feeding. Furthermore, 36% ethanol-feeding for 1 week stimulated rat tracheal CBF and PKA. CONCLUSION These data demonstrate that in vivo administration of ethanol to rats results in decreased ciliary beating and the desensitization of PKA. This suggests a mechanism for mucociliary clearance dysfunction in alcoholics.