Low dose of moxonidine within the rostral ventrolateral medulla improves the baroreflex sensitivity control of sympathetic activity in hypertensive rat
Low dose of moxonidine within the rostral ventrolateral medulla improves the baroreflex sensitivity control of sympathetic activity in hypertensive rat
复制标题
DOI：
10.1038/aps.2009.165
复制
发表时间：
2009-12
期刊：
影响因子：
--
通讯作者：
Jia-ling Wang;Long Wang;Zhao-tang Wu;W. Yuan;D. Su;Xin Ni;Jian-jun Yan;Wei-Zhong Wang
中科院分区：
文献类型：
--
作者：
Jia-ling Wang;Long Wang;Zhao-tang Wu;W. Yuan;D. Su;Xin Ni;Jian-jun Yan;Wei-Zhong Wang
目的：观察中枢性降压药莫硝定经吻侧腹外侧髓质注射对自发性高血压大鼠（SHR）压力反射功能的影响。方法：测定不同剂量莫昔定对肾交感神经活动（RSNA）的压力反射敏感性控制及RVLM前交感神经元的压力敏感性。结果：三种剂量（0.05、0.5和5nmol / 50nl）的莫昔定双侧注射于RVLM内，剂量依赖性地降低了SHR的基线血压（BP）和RSNA。莫昔定注射最高剂量（5 nmol）时，RSNA压力反射对照的最大增益（1.24%±0.04%/mmHg）显著降低。而低剂量（0.05和0.5 nmol）的莫昔定可显著提高压力反射增益（2.34%±0.08%和2.01%±0.07%/mmHg）。咪唑啉受体拮抗剂依法罗康可以完全阻止莫替尼定诱导的反射功能增强，而α 2-肾上腺素受体拮抗剂育亨宾则不能。SHR大鼠RVLM细胞外共记录到48个前交感神经元。应用莫onidiine （30-60 nA）离子导入可剂量依赖性地降低RVLM前交感神经元的放电，但也显著增加RVLM前交感神经元的压力敏感性。结论：RVLM内低剂量莫昔定可通过咪唑啉受体依赖机制改善SHR的压力反射功能。
Aim:To determine the effects of the centrally antihypertensive drug moxonidine injected into the rostral ventrolateral medulla (RVLM) on baroreflex function in spontaneously hypertensive rats (SHR).Methods:Baroreflex sensitivity control of renal sympathetic nerve activity (RSNA) and barosensitivity of the RVLM presympathetic neurons were determined following application of different doses of moxonidine within the RVLM.Results:Three doses (0.05, 0.5, and 5 nmol in 50 nL) of moxonidine injected bilaterally into the RVLM dose-dependently reduced the baseline blood pressure (BP) and RSNA in SHR. At the highest dose (5 nmol) of moxonidine injection, the maximum gain (1.24%±0.04%/mmHg) of baroreflex control of RSNA was significantly decreased. However, the lower doses (0.05 and 0.5 nmol) of moxonidine injection into the RVLM significantly enhanced the baroreflex gain (2.34%±0.08% and 2.01%±0.07%/mmHg). The moxonidine-induced enhancement in baroreflex function was completely prevented by the imidazoline receptor antagonist efaroxan but not by the α 2-adrenoceptor antagonist yohimbine. A total of 48 presympathetic neurons were recorded extracellularly in the RVLM of SHR. Iontophoresis of applied moxonidine (30–60 nA) dose-dependently decreased the discharge of RVLM presympathetic neurons but also significantly increased the barosensitivity of RVLM presympathetic neurons.Conclusion:These data demonstrate that a low dose of moxonidine within the RVLM has a beneficial effect on improving the baroreflex function in SHR via an imidazoline receptor-dependent mechanism.