孤束核微注射内皮素-1对高血压大鼠心血管活动的影响

目的研究内皮素－１（ＥＴ－１）在孤束核对高血压大鼠心血管活动的作用。方法乌拉坦麻醉大鼠单侧孤束核微注射ＥＴ－１或ＥＴ受体拮抗剂后，观察血压、心率、左室收缩压和±ｄｐ／ｄｔｍａｘ的变化。结果在乌拉坦麻醉的ＷＫＹ大鼠和自发性高血压大鼠（ＳＨＲ），单侧孤束核微注射１．０ｐｍｏｌ或３．３ｐｍｏｌ的ＥＴ－１均可引起血压、左室收缩压和±ｄｐ／ｄｔｍａｘ升高，呈剂量依赖性；心率轻度减慢，与剂量不相关。血压持续升高９０ｍｉｎ以上。ＳＨＲ的心血管反应强度与ＷＫＹ大鼠无显著差异。孤束核微注射非选择性ＥＴＡ／ＥＴＢ受体拮抗剂ＰＤ１４２８９３对ＳＨＲ和ＷＫＹ大鼠的血压和心率均无明显影响。结论孤束核ＥＴ－１与ＳＨＲ的血压增高无关

Cardiovascular responses evoked by endothelin 1 microinjected intothe nucleus tractus solitarius of hypertensive rats

AIM To study the role of endothelin 1(ET 1), a potent vasoconstrictor originally isolated from vascular endothelial cells, within the nucleus tractus solitarius (NTS) of spontaneously hypertensive rats (SHR) in central cardiovascular control. METHODS To observe changes in blood pressure, heart rate, left ventricular systolic pressure and ±dp/dtmax after a unilateral microinjection of ET 1 or ET receptor antagonist into the NTS of urethane anesthetized rats. RESULTS In SHR and WKY rats, a unilateral microinjection of ET 1 (10, 33 pmol) into the NTS significantly increased arterial pressure, left ventricular systolic pressure and dp/dtmax in a dose dependent manner,and slightly decreased heart rate in a non dose dependent manner. The pressor response lasted more than 90 minutes. In either SHR or WKY rats, a non selective ETA/ETB receptor antagonist PD 142893 microinjected into the NTS elicited no changes in arterial pressure or heart rate. CONCLUSION The role of ET 1 within the NTS is not related to the hypertension of SHR.