Circadian expression of clock genes and angiotensin Ⅱ type 1 receptors in suprachiasmatic nuclei of sinoaortic-denervated rats  

作　　者：Hui LI Ning-ling SUN Jin WANG Ai-junLIU Ding-feng SU 

机构地区：[1]Department of Cardiology, Peking University People's Hospital, Beijing 100044, China [2]Department of Pharmacology, Second Military Medical University, Shanghai 200433, China

出　　处：《Acta Pharmacologica Sinica》2007年第4期484-492,共9页中国药理学报（英文版）

基　　金：Project was partially supported by the National Natural Science Foundation of China(№ 30330650)

摘　　要：Aim： To investigate whether the circadian expression of central clock genes and angiotensin Ⅱ type 1 （ATI） receptors was altered in sinoaortic-denervated （SAD） rats. Methods： Male Sprague-Dawley rats underwent sinoaortic denervation or a sham operation at the age of 12 weeks. Four weeks after the operation, blood pressure and heart period were measured in the conscious state in a group of sham-operated （n= 10） and SAD rats （n=9）. Rest SAD and sham-operated rats were divided into 6 groups （n=6 in each group）. The suprachiasmatic nuclei （SCN） tissues were taken every 4 h throughout the day from each group for the determination of the mRNA expression of clock genes （Per2 and Bmall） and the AT1 receptor by RT-PCR; the protein expression of Per2 and Bmal I was determined by Western blotting. Results： Blood pressure levels in the SAD rats were similar to those of the sham-operated rats. However, blood pressure variabilities significantly increased in the SAD rats compared with the sham-operated rats. The circadian variation of clock genes in the SCN of the sham-operated rats was characterized by a marked increase in the mRNA and protein expression during dark periods. Per2 and Bmall mRNA levels were significantly lower in the SAD rats, especially during dark periods. Western blot analysis confirmed an attenuation of the circadian rhythm of the 2 clock proteins in the SCN of the SAD rats. ATI receptor mRNA expressions in the SCN were abnormally upregulated in the light phase, changed to a 12-h cycle in the SAD rats. Condusion： The circadian variation of the 2 central clock genes was attenuated in the SAD rats. Arterial baroreflex dysfunction also induced a disturbance in the expression of ATI receptors in the SCN.Aim： To investigate whether the circadian expression of central clock genes and angiotensin Ⅱ type 1 （ATI） receptors was altered in sinoaortic-denervated （SAD） rats. Methods： Male Sprague-Dawley rats underwent sinoaortic denervation or a sham operation at the age of 12 weeks. Four weeks after the operation, blood pressure and heart period were measured in the conscious state in a group of sham-operated （n= 10） and SAD rats （n=9）. Rest SAD and sham-operated rats were divided into 6 groups （n=6 in each group）. The suprachiasmatic nuclei （SCN） tissues were taken every 4 h throughout the day from each group for the determination of the mRNA expression of clock genes （Per2 and Bmall） and the AT1 receptor by RT-PCR; the protein expression of Per2 and Bmal I was determined by Western blotting. Results： Blood pressure levels in the SAD rats were similar to those of the sham-operated rats. However, blood pressure variabilities significantly increased in the SAD rats compared with the sham-operated rats. The circadian variation of clock genes in the SCN of the sham-operated rats was characterized by a marked increase in the mRNA and protein expression during dark periods. Per2 and Bmall mRNA levels were significantly lower in the SAD rats, especially during dark periods. Western blot analysis confirmed an attenuation of the circadian rhythm of the 2 clock proteins in the SCN of the SAD rats. ATI receptor mRNA expressions in the SCN were abnormally upregulated in the light phase, changed to a 12-h cycle in the SAD rats. Condusion： The circadian variation of the 2 central clock genes was attenuated in the SAD rats. Arterial baroreflex dysfunction also induced a disturbance in the expression of ATI receptors in the SCN.

关 键 词：circadian rhythm arterial baroreflex clockgenes sinoaortic denervation reninangiotensin system 

分 类 号：Q41[生物学—生理学] Q75