Judy W V, Watanabe A M, Henry D P, Besch H R, Aprison B
Circ Res. 1978 Jul;43(1):24-8. doi: 10.1161/01.res.43.1.24.
We examined the effect of L-Dopa, after peripheral L-amino acid decarboxylase inhibition, on sympathetic nerve activity (SNA) and blood pressure in spontaneously hypertensive rats (SHR) and in normotensive control rats. L-Dopa reduced SNA in both groups of animals. The SHRs were significantly more sensitive to the depressor effect of L-dopa than were the control animals, the threshold dose for reduction of SNA being 3 mg/kg in the SHR and 15 mg/kg in control rats. Similarly, the magnitude of inhibition of SNA was substantially greater in the SHR than in normotensive rats. The reduction in SNA in the SHR accompanied by a parallel fall in blood pressure. In contrast, blood pressure in control rats did not change significantly, even though SNA was diminished. Studies of the penetration of L-dopa into the cerebral parenchyma revealed that equivalent amounts of the amino acid entered the brains of the two groups of rats. These results suggest that the SHRs are more sensitive to the SNA-inhibiting effects of L-dopa than are normotensive rats. In addition, they confirm our previous suggestion that excessive SNA plays a causative role in the hypertension of the SHR.
我们研究了在外周左旋氨基酸脱羧酶受到抑制后，左旋多巴对自发性高血压大鼠（SHR）和正常血压对照大鼠的交感神经活动（SNA）及血压的影响。左旋多巴降低了两组动物的SNA。SHR对左旋多巴的降压作用比对照动物明显更敏感，降低SNA的阈剂量在SHR中为3mg/kg，在对照大鼠中为15mg/kg。同样，SHR中SNA的抑制幅度比正常血压大鼠大得多。SHR中SNA的降低伴随着血压的平行下降。相比之下，对照大鼠的血压没有明显变化，尽管SNA有所降低。对左旋多巴进入脑实质的研究表明，等量的这种氨基酸进入了两组大鼠的大脑。这些结果表明，SHR对左旋多巴抑制SNA的作用比正常血压大鼠更敏感。此外，它们证实了我们之前的观点，即过度的SNA在SHR的高血压中起致病作用。
