自发性高血压大鼠孤束核中对嘌呤能A2刺激的心血管反应改变。

Altered cardiovascular responses to purinergic A2 stimulation in the nucleus tractus solitarius of spontaneously hypertensive rats.

作者信息

Tanaka M, Takeda K, Takesako T, Takenaka K, Itoh H, Nakata T, Sasaki S, Nakagawa M

机构信息

Second Department of Medicine, Kyoto Prefectural University of Medicine, Japan.

出版信息

J Hypertens. 1995 Nov;13(11):1285-90. doi: 10.1097/00004872-199511000-00010.

DOI:10.1097/00004872-199511000-00010

PMID:8984126

Abstract

OBJECTIVE

To investigate the cardiovascular effects of adenosine A2 receptor stimulation in the nucleus tractus solitarius and whether these effects are altered in hypertension.

DESIGN AND METHODS

Ten- or 11-week-old spontaneously hypertensive rats (SHR) or Wistar-Kyoto (WKY) rats were anaesthetized with urethane. Adenosine (100 ng) or adenosine A2 agonist (2-octynyladenosine, 5 ng) were micro-injected (50 nl) into the nucleus tractus solitarius. Blood pressure and heart rate were measured from a femoral artery. Sympathetic nerve activity was recorded from the abdominal splanchnic nerve.

RESULTS

Blood pressure, heart rate and sympathetic nerve activity were consistently decreased after the micro-injection of adenosine into normotensive rats. Changes from the baseline in blood pressure, heart rate and sympathetic nerve activity were significantly smaller in SHR than in WKY rats (blood pressure: SHR -5.6 +/- 2.1% versus WKY rats -20.0 +/- 2.1%; heart rate: SHR -5.4 +/- 0.88% versus WKY rats -9.2 +/- 2.3%; sympathetic nerve activity: SHR -5.5 +/- 1.1% versus WKY rats -21 +/- 2.8%). Micro-injection of an A2 agonist into the nucleus tractus solitarius also decreased blood pressure and heart rate, and those responses were not inhibited by pretreatment with an adenosine A1-specific antagonist. The response induced by micro-injection of A2 agonist into the nucleus tractus solitarius was significantly smaller in SHR than in WKY rats, whereas the changes in heart rate did not differ statistically (blood pressure: -23.4 +/- 4.7% versus -10.8 +/- 2.1%; heart rate: -12.1 +/- 1.2% versus -13.6 +/- 2.1%).

CONCLUSION

The present results suggest that stimulation of adenosine A2 receptors in the nucleus tractus solitarius decreases both blood pressure and inhibitory sympathetic nerve activity and that those inhibitory responses to adenosine in the nucleus tractus solitarius are deranged in SHR.

摘要

目的

研究孤束核中腺苷A2受体刺激对心血管系统的影响，以及在高血压状态下这些影响是否发生改变。

设计与方法

选用10或11周龄的自发性高血压大鼠（SHR）或Wistar-Kyoto（WKY）大鼠，用乌拉坦麻醉。将腺苷（100 ng）或腺苷A2激动剂（2-辛炔腺苷，5 ng）微量注射（50 nl）到孤束核中。通过股动脉测量血压和心率。从腹内脏神经记录交感神经活动。

结果

向正常血压大鼠微量注射腺苷后，血压、心率和交感神经活动持续降低。SHR大鼠血压、心率和交感神经活动相对于基线的变化显著小于WKY大鼠（血压：SHR -5.6±2.1%，WKY大鼠 -20.0±2.1%；心率：SHR -5.4±0.88%，WKY大鼠 -9.2±2.3%；交感神经活动：SHR -5.5±1.1%，WKY大鼠 -21±2.8%）。向孤束核微量注射A2激动剂也可降低血压和心率，且这些反应不受腺苷A1特异性拮抗剂预处理的抑制。向孤束核微量注射A2激动剂所诱导的反应在SHR大鼠中显著小于WKY大鼠，而心率变化在统计学上无差异（血压：-23.4±4.7% 对 -10.8±2.1%；心率：-12.1±1.2% 对 -13.6±2.1%）。