高血压大鼠中脑导水管周围灰质内nNOS样阳性神经元的变化

目的：观察高血压大鼠中脑导水管周围灰质(PAG)内神经元型一氧化氮合酶(nNOS)样阳性神经元数量的变化。方法：用双肾双夹法建立高血压大鼠模型，ABC法显示PAG内nNOS样阳性神经元并进行定量分析。结果：nNOS样阳性神经元分布于PAG的背外侧区。PAG内nNOS样阳性神经元的数量、光密度在对照组各时期无明显变化；在高血压大鼠7d时的数量略减少，光密度略下降；而在30d、70d则数量、光密度逐渐减少，与对照组比较差异显著。结论：中脑PAG内nNOS样阳性神经元及阳性产物的减少可能与其对心血管功能活动、感觉信息传导的影响以及高血压的形成和发展有关。

Changes of neuronal nitric oxide synthase immunopositive neurons in midbrain periaqueductal gray of hypertensive rats

Objective: To observe the changes of neuronal nitric oxide synthase (nNOS) immunopositive (IP) neurons in the midbrain periaqueductal gray (PAG) of the hypertensive rats. Methods:Hypertensive rats were made with double kidney-double clip technique. nNOS-IP neurons were revealed with ABC immunocytochemical method and quantitatively analyzed by image analyzer. Results:nNOS-IP neurons were mainly located in the dorsal lateral region of the PAG. These nNOS-IP neurons, most of them were small cells and deeply stained. They were triangle, fusiform and round in shape. Moreover, the neurons had 1-4 long processes that intersected each other, and many of them extended to medial ventral region of the PAG. Ratio analysis showed the following results: In control group, the number and optical density of nNOS-IP neurons in the dorsal lateral region of the PAG had no significant difference during all the periods. In hypertensive rats, the number and optical density of nNOS-IP neurons reduced slightly, and there were no significant difference on the 7th day. These changes were apparent on the 30th or 70th day, especially on the 70th day, compared with the control rats (P<0.05). Conclusion:The gradual reduction of nNOS-IP neurons in dorsal lateral region of the PAG may take part in the development of hypertension by influencing the cardiovascular function and sensory information conduction.