大鼠延髓腹外侧注射食欲刺激素对动脉压和心率的影响
Ghrelin Effect at the Ventrolateral Medulla to Arterial Pressure and Heart Rate in Rats
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摘要: 目的探讨在大鼠延髓腹外侧注射食欲刺激素是否影响动脉压和心率。方法成熟雄性大鼠(n=19)腹腔内麻醉,微量注射食欲刺激素于延髓腹外侧头端(RVLM)及延髓腹外侧尾端(CVLM)内,记录动脉压和心率。用免疫组化的方法检测 RVLM、CVLM 内生长激素促分泌素(GHS)受体蛋白的表达,并在显微镜下观察孤束核、RVLM、CVLM 区切片,记数阳性细胞数进行对比。结果微量注射食欲刺激素(0.4、0.8 mmol/L)于 RVLM内,可增加动脉压(+3.0±1.1)mmHg 和心率(+8.1±4.1)次/min,但差异没有统计学意义。同样微量注射食欲刺激素0.8 mmol/L 于 CVLM 内对动脉压(-0.3±1.3)mmHg及心率(-5.0±3.3)次/min的影响,差异也没有统计学意义。免疫组化显示孤束核(38.7±3.6)%、RVLM(20.0±2.7)%、CVLM(24.7±1.6)%内均有GHS 受体的分布。但是,孤束核的 GHS 受体阳性细胞数明显多于 RVLM、CVLM(P<0.05)。结论食欲刺激素在大鼠延髓腹外侧内对动脉压和心率影响不大。Abstract: Objective The aim of the present study was to determine the role of ghrelin in the ventrolateral medulla in regulation of arterial pressure and heart rate in rats.Metheods Rats（n=19）were anesthetized with u- rethane.We administered a microinjection of ghrelin（0.4,0.8 mmol/L）within the caudal ventrolateral medulla （CVLM）and the rostral ventrolateral medulla（RVLM）,and recording of arterial pressure and heart rate.Immu- nohistochemicaI study was using to reveal that the receptor for ghrelin,the growth hormone secretagogue（GHS）re- ceptor.Results Unilateral microinjeetion of ghrelin into the RVLM and CVLM caused no significant changes in the mean arterial pressure and heart rate.GHS receptor was expressed in the neuronal cells of the nucleus of the solita- ry tract（NTS）and the ventrolateral medulla,and the number receptors were significantly greater in the NTS（NTS: 38.7%±3.6%,RVLM:20.0%±2.7%,CVLM:24.7%±1.6%,P＜0.05）.Conclusion Although ghrelin re eeptors were exhibited in CVLM and RVLM,their function did not relate with regulation of arterial pressure and heart rate.
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