Received 2002-04-11 Accepted 2002-06-06

*Corresponding author. Tel:+86-311-6062490; Fax:+86-311-6062490;   

E-mail: syho@hebmu.edu.cn

 

Microinjection of adrenomedullin into rostral ventrolateral medulla increases blood pressure,heart rate and renal sympathetic nerve activity in rats

JI Shu-Mei,     HE Rui-Rong*

Department of Physiology, Hebei Medical University, Shijiazhuang 050017

 

Abstract:  The present study was undertaken to examine the effects of microinjection of  adrenomedullin (AM) into rostral ventrolateral medulla (RVLM) on mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) in 34 anesthetized Sprague-Dawley rats. The results obtained are as follows.  (1) Following microinjection of AM (10  μmol/L, 200 nl) into the RVLM, MAP, HR and RSNA were significantly increased from 99.09±3.32 mmHg, 370.78±7.84 bpm and 100±0% to 113.57±3.64 mmHg (P<0.001), 383.28±7.38 bpm (P<0.001) and 123.72±2.74% (P<0.001), respectively. (2) Pretreatment with microinjection of calcitonin gene-related peptide receptor antagonist CGRP8-37 (100  μmol/L, 200 nl) did not change the effects of AM. (3) L-arginine (100 mg/kg, 0.2 ml, i.v.), an NO precursor, abolished the effects of AM.  This study demonstrates that AM acting at the rostral ventrolateral medulla may produce significant cardiovascular responses, the effects are not mediated by CGRP receptor but may be abolished by NO.

 

Key words: adrenomedullin; rostral ventrolateral medulla; mean arterial pressure; heart rate; renal sympathetic nerve; calcitonin gene-related peptide receptor antagonist; L-arginine

 

延髓腹外侧头端区注射肾上腺髓质素对大鼠血压、 心率和肾交感神经活动的影响

季淑梅,  何瑞荣

河北医科大学基础医学研究所生理室,  石家庄 050017

摘要:  本研究在34只麻醉Sprague-Dawley大鼠观察了延髓腹外侧头端区内微量注射肾上腺髓质素(10  μmol/L, 200 nl)对平均动脉压(MAP)、 心率(HR)和肾交感神经放电(RSNA)的影响。实验结果如下: (1) 延髓腹外侧头端区内微量注射肾上腺髓质素可引起MAP、 HR、 和RSNA明显增加, 分别由99.09±3.32 mmHg, 370.78±7.84 bpm 和 100±0% 增至113.57±3.64 mmHg (P<0.001), 383.28 ±7.38 bpm (P<0.001) 和123.72±2.74% (P<0.001); (2) 降钙素基因相关肽受体阻断剂CGRP8-37 (100  μmol/L, 200 nl)不能阻断肾上腺髓质素的上述效应; (3) 静脉注射NO前体L-精氨酸(100 mg/kg, 0.2 ml)可消除肾上腺髓质素的上述效应。以上结果提示, 肾上腺髓质素作用于延髓腹外侧头端区可产生显著的心血管作用, 此作用不是由降钙素基因相关肽受体介导,但可被NO所阻断。

 

关键词: 肾上腺髓质素; 延髓腹外侧头端区;  平均动脉压; 心率; 肾交感神经; 降钙素基因相关肽受体拮抗剂; L-精氨酸

中图分类号: Q463