烟碱对脑钾、钠和钙通道表达的调节作用

MODULATION BY NICOTINE ON THE GENES EXPRESSION OF BRAIN POTASSIUM, SODIUM AND CALCIUM CHANNELS

目的利用基因表达芯片检测反复摄取烟碱对大鼠脑内钾、钠和钙通道基因表达的调节作用。方法大鼠每天两次皮下注射烟碱(1.2mg/kg),连续用药两周后取全脑,提取RNA,逆转录合成cDNA,转录合成生物素化RNA,并将其片断化后与芯片杂交,对荧光信号扫描分析。结合RTPCR方法对芯片分析结果进行验证。结果反复摄入烟碱,大鼠脑内钾、钠和钙通道的基因表达均发生变化电压依赖性K+通道中外向整流K+通道和Ca2+激活的K+通道表达下调,而Kv2.3r等电压依赖性K+通道表达上调;电压依赖性Na+通道中β2亚基表达增加,而α和β1亚基基因表达减少;电压依赖性Ca2+通道的β3亚基基因表达增加。结论反复摄取烟碱诱导脑N受体失敏时,可引起相关钾、钠和钙通道基因表达发生改变。

Aim: Using GeneChip to analyze the changes in genes expression of brain potassium,sodium and calcium channels after chronic treatment with nicotine. Methods: Animals were treated with nicotine at the doses of 2.4 mg/kg sc. twice a day for 14 days. RNA was extracted from the whole brain samples and converted to double stranded cDNA and then to biotinylated cRNA. The biotinylated cRNA was fragmented, and hybridized to GeneChip (Affymetrix Rat Neurobiology U34). The chips were scanned with a probe array scanner, and the data were analyzed with the Affymetrix Microarray Analysis Suite (MAS). The GeneChip data were confirmed u sing RT PCR. Results: After treatment with chronic nicotine, transcripts of potassium, sodium and calcium channels showed altered expression. K + channel: outward rectifer K + channel and Ca 2+ activated K + channel were down regulated, other voltage dependent K + channel including Kv2.3r were up regulated. Voltage dependent Na + channel: β 2 subunit was increased, α subunit and β 1 subunit were decreased. β 3 subunit of Ca 2+ channel was up regulated. Conclusion: Chronic exposure to nicotine not only desensitized nicotinic receptors, but also effected genes expression of important ion channels, such as sodium channels, potassium channels and calcium channels.