P物质及儿茶酚胺在海仁酸刺激延髓腹侧面头端引起的升压反应中的作用

海仁酸(KA)刺激大鼠延髓腹侧面头端(RVM)引起血压上升,同时伴有脊髓胸段和延髓的P物质样免疫活性(SPLI)降低.血浆去甲肾上腺素(NA)和肾上腺素(AD)含量增高;而中枢各脑区的NA和AD含量无明显变化。脊髓蛛网膜下腔注射(ith)P物质(SP)拮抗剂D-脯~2,D-苯丙~7,D-色~9-P物质(D-SP)可拮抗KA引起的增高血浆NA和AD的作用,从而阻断了KA的升压效应。提示延髓—脊髓SP能下行通路与交感肾上腺髓质系统参与KA的升压效应;而中枢儿茶酚胺系统不参与作用.

The Role of Substance P and Catecholamine in the Mechanism of Pressor Response Elicited by Application of Kainic Acid to the Rostral Ventral Surface of the Medulla Oblongata in Rat

Application of kainic acid (KA) to the rostral ventral surface of the medulla oblongata (RVM) produced an increase in mean arterial pressure, accompanied by a decrease in substance P-like immunoreactivity in both spinal cord and medulla oblongata and an elevation of plasma adrenaline (AD) and noradrenaline (NA) content. There were no significant changes in the amounts of AD and NA in other areas of the central nervous system. These responses were effectively abolished by pre-intrathecal injection of D-pro2, D-phe7 or D-Trp9-SP.These results suggest that the pressor responses evoked by activation of RVM might be mediated by a substance P (SP)-containing bulbospinal pathway rather than by a central catecholamine system. SP transmits exit-atory information from RVM to the peripheral vasculature via the spinal sympathetic adrenal medulla system, which plays an important role in maintaining vasomotor tone.