辣椒素引起脊髓 P 物质释放及其对血压的影响

EFFECT OF CAPSAICIN ON THE RELEASE OF SUBSTANCE P FROM SPINAL CORD AND BLOOD PRESSURE

为进一步研究脊髓 P 物质(SP)在调节心血管活动中的作用,在大鼠脊髓蛛网膜下腔注射(ith)辣淑素(cap),以刺激脊髓 SP 能神经末梢释放 SP,结果引起血浆去甲肾上腺素(NA)和肾上腺素(AD)含量增高,及具有剂量依赖性的动脉血压上升,心率升高。ith 具有高度特异性的 SP 受体拮抗剂或 SP 抗血清均可阻断 cap 引起的升压效应,免疫组化测定也观察到注入的cap 剂量越大,脊髓胸段 SP 样免疫阳性反应物的致密度越低,这些观察结果支持 cap 可以引起脊髓内 SP 的释放的说法。在第一颈段(C_1)横断脊髓后 ith cap 所引起的升压效应与完整动物 ith cap 的升压效应无显著差异。以上结果提示脊髓 SP 能神经末梢释放的 SP 可以通过交感肾上腺髓质系统引起心血管兴奋效应,SP 可能是引起交感节前神经元兴奋的神经递质。

The role of substance P(SP)in the regulation of sympathetic outflow to thecardiovascular system was assessed.Intrathecal injection(ith)of capsaicin causeda release of SP from the spinal cord and resulted in an increase in blood pressureand heart rate accompanied by an elevation of plasma adrenaline and noradrenalineThis pressor response was blocked by ith SP antagonist D-Pro^2,D-Phe^7,D-Trp^9-SPor antiserum against SP.The immunohistochemical study showed that the SP-likeimmunoreactivity in T-8 of the spinal cord was decreased as the amount of capsai-cin administrated was increased Spinal cord transection had no effect on pressorresponses caused by ith 10 μg capsaicin.These results suggest that SP transmitsexcitatory information to the cardiovascular system via spinal sympathetic pathway.