纳洛酮在延髓腹外侧加压区加强P物质引起的升压效应

PRESSOR EFFECT OF SUBSTANCE P WAS STRENGTHENED BY NALOXONE IN THE PRESSOR AREA OF VENTRAL SURFACE OF MEDULLA IN RABBITS

目的：探讨Ｐ物质（ＳＰ）在延髓腹外侧加压区（ＶＳＭｐ）的升压效应是否与内源性阿片样物质有关。方法：氨基甲酸乙酯麻醉、人工呼吸，暴露延髓腹侧面，ＶＳＭｐ 敷贴ＳＰ等药物。结果：ＶＳＭｐ 敷贴ＳＰ可使血压呈剂量效应关系的明显增高，但心率无明显变化；在ＶＳＭｐ 给纳洛酮进行预处理，可显著增强ＳＰ的升压效应；应用神经元细胞体兴奋剂Ｌ谷氨酸钠到ＶＳＭｐ 可使血压显著升高。结论：ＳＰ 在ＶＳＭｐ 具有明显的升压作用，内源性阿片样物质在ＶＳＭｐ 对ＳＰ升压效应起拮抗作用，ＳＰ的升压效应可能是兴奋ＶＳＭｐ

Aim and Methods:Cardiovascullar effect of substance P (SP) in the pressor area of ventral surface of medullar oblongata (VSMp) and its underlying mechanism were investigated in urethane anesthetized and artificially ventilated rabbits. Results:The application of SP (0. 05 μg) to VSMp produced a dose dependent increase in arterial blood presure (BP) (2.1±0.1)kPa, but did not result in obvious changes in heart rate.Whereas the application of SP sites outside this area elicited a very small and insignificant response. Pretreatment with naloxone (1.0 μg) to the VSMp strengthened the pressor response of SP (3.6±0.8)kPa. The application of L sodium glutamate (exciting only cell bodies) (15 μg) to VSMp gave rise to remarkable increase in BP (7.8±1.7)kPa.Conclusion: The above results suggest that SP in VSMp plays an important role in BP control. The vasopressor effect of VSMp administered SP was attenuated by the release of some endogenous opioids and it was probablly due to the actions on cell bodies rather than axons.